text: A new top-level full-sized model was introduced at mid-year 1959, the Ford Galaxie. The 1959 Galaxie displayed both "Fairlane 500" and "Galaxie" badging.

text: A new top-level full-sized model was introduced at mid-year 1959, the

entity_name: Ford Galaxie

text: Ford Galaxie

text: . The 1959 Galaxie displayed both "Fairlane 500" and "Galaxie" badging.

text: ESO 137-001 is a barred spiral galaxy located in the cluster known as Abell 3627 (Norma Cluster). As the galaxy moves to the center of the cluster, it is stripped by hot gas thus creating a 260,000 light-year long tail. There is evidence of star formation in the tails. The galaxy was discovered by Dr. Ming Sun in 2005.

text: ESO 137-001 is a

entity_name: Barred spiral galaxy

text: barred spiral galaxy

text: located in the cluster known as

entity_name: Norma Cluster

text: Abell 3627

text: (Norma Cluster). As the galaxy moves to the center of the cluster, it is stripped by hot gas thus creating a 260,000

entity_name: Light-year

text: light-year

text: long tail. There is evidence of star formation in the tails. The galaxy was discovered by Dr. Ming Sun in 2005.

text: Groups and clusters of galaxies have a wider range of velocity dispersions than smaller objects. For example, our own poor group, the  Local Group, has a σ = 61±8 km/s. But rich clusters of galaxies, such as the Coma Cluster, have a σ ≈ 1,000 km/s. The dwarf elliptical galaxies in Coma have their own, internal, velocity dispersion for their stars, which is a σ ≲ 80 km/s, typically. Normal elliptical galaxies, by comparison, have an average σ ≈ 200 km/s.

text: Groups and clusters of galaxies have a wider range of velocity dispersions than smaller objects. For example, our own

entity_name: Abell catalogue

entity_section: Richness

text: poor group

text: , the

entity_name: Local Group

text: Local Group

text: , has a σ = 61±8 km/s. But rich clusters of galaxies, such as the

entity_name: Coma Cluster

text: Coma Cluster

text: , have a σ ≈ 1,000 km/s. The

entity_name: Dwarf elliptical galaxy

text: dwarf elliptical galaxies

text: in Coma have their own, internal, velocity dispersion for their stars, which is a σ ≲ 80 km/s, typically. Normal

entity_name: Elliptical galaxy

text: elliptical galaxies

text: , by comparison, have an average σ ≈ 200 km/s.

text: The organization of structure arguably begins at the stellar level, though most cosmologists rarely address astrophysics on that scale. Stars are organized into galaxies, which in turn form galaxy groups, galaxy clusters, superclusters, sheets, walls and filaments, which are separated by immense voids, creating a vast foam-like structure sometimes called the "cosmic web". Prior to 1989, it was commonly assumed that virialized galaxy clusters were the largest structures in existence, and that they were distributed more or less uniformly throughout the Universe in every direction. However, since the early 1980s, more and more structures have been discovered. In 1983, Adrian Webster identified the Webster LQG, a large quasar group consisting of 5 quasars. The discovery was the first identification of a large-scale structure, and has expanded the information about the known grouping of matter in the Universe. In 1987, Robert Brent Tully identified the Pisces–Cetus Supercluster Complex, the galaxy filament in which the Milky Way resides. It is about 1 billion light years across. That same year, an unusually large region with no galaxies has been discovered, the Giant Void, which measures 1.3 billion light years across. Based on redshift survey data, in 1989 Margaret Geller and John Huchra discovered the "Great Wall", a sheet of galaxies more than 500 million light-years long and 200 million wide, but only 15 million light-years thick. The existence of this structure escaped notice for so long because it requires locating the position of galaxies in three dimensions, which involves combining location information about the galaxies with distance information from redshifts.Two years later, astronomers Roger G. Clowes and Luis E. Campusano discovered the Clowes–Campusano LQG, a large quasar group measuring two billion light years at its widest point, and was the largest known structure in the Universe at the time of its announcement. In April 2003, another large-scale structure was discovered, the Sloan Great Wall. In August 2007, a possible supervoid was detected in the constellation Eridanus. It coincides with the 'CMB cold spot', a cold region in the microwave sky that is highly improbable under the currently favored cosmological model. This supervoid could cause the cold spot, but to do so it would have to be improbably big, possibly a billion light-years across, almost as big as the Giant Void mentioned above.

text: The organization of structure arguably begins at the stellar level, though most cosmologists rarely address

entity_name: Astrophysics

text: astrophysics

text: on that scale.

entity_name: Star

text: Star

text: s are organized into

entity_name: Galaxy

text: galaxies

text: , which in turn form

entity_name: Galaxy group

text: galaxy group

text: s,

entity_name: Galaxy cluster

text: galaxy cluster

text: s,

entity_name: Supercluster

text: supercluster

text: s, sheets,

entity_name: Galaxy filament

text: walls and filaments

text: , which are separated by immense

entity_name: Void (astronomy)

text: voids

text: , creating a vast foam-like structure sometimes called the "cosmic web". Prior to 1989, it was commonly assumed that

entity_name: Virial theorem

text: virialized

text: galaxy clusters were the largest structures in existence, and that they were distributed more or less uniformly throughout the Universe in every direction. However, since the early 1980s, more and more structures have been discovered. In 1983, Adrian Webster identified the Webster LQG, a

entity_name: Large quasar group

text: large quasar group

text: consisting of 5 quasars. The discovery was the first identification of a large-scale structure, and has expanded the information about the known grouping of matter in the Universe. In 1987, Robert Brent Tully identified the

entity_name: Pisces–Cetus Supercluster Complex

text: Pisces–Cetus Supercluster Complex

text: , the galaxy filament in which the Milky Way resides. It is about 1 billion light years across. That same year, an unusually large region with no galaxies has been discovered, the

entity_name: Giant Void

text: Giant Void

text: , which measures 1.3 billion light years across. Based on

entity_name: Redshift survey

text: redshift survey

text: data, in 1989

entity_name: Margaret Geller

text: Margaret Geller

text: and

entity_name: John Huchra

text: John Huchra

text: discovered the "

entity_name: CfA2 Great Wall

text: Great Wall

text: ", a sheet of galaxies more than 500 million

text: light-year

text: s long and 200 million wide, but only 15 million light-years thick. The existence of this structure escaped notice for so long because it requires locating the position of galaxies in three dimensions, which involves combining location information about the galaxies with distance information from

entity_name: Redshift

text: redshift

text: s.Two years later, astronomers Roger G. Clowes and Luis E. Campusano discovered the

entity_name: Clowes–Campusano LQG

text: Clowes–Campusano LQG

text: , a

text: large quasar group

text: measuring two billion light years at its widest point, and was the largest known structure in the Universe at the time of its announcement. In April 2003, another large-scale structure was discovered, the

entity_name: Sloan Great Wall

text: Sloan Great Wall

text: . In August 2007, a possible supervoid was detected in the constellation

entity_name: Eridanus (constellation)

text: Eridanus

text: . It coincides with the '

entity_name: CMB cold spot

text: CMB cold spot

text: ', a cold region in the microwave sky that is highly improbable under the currently favored cosmological model. This supervoid could cause the cold spot, but to do so it would have to be improbably big, possibly a billion light-years across, almost as big as the Giant Void mentioned above.

method: UNH-ecn

text: There are two main shape groups: "round pads" and long narrow pads called "bar pads". Pads are also made in other shapes, called "loaf pads". Within each group there are three size categories: small, medium, and large size pads. It is also possible to engineer custom-shaped pads to meet special application requirements.

method: dangnt-nlp

text: In weak gravitational lensing, the Jacobian is mapped out by observing the effect of the shear on the ellipticities of background galaxies.  This effect is purely statistical; the shape of any galaxy will be dominated by its random, unlensed shape, but lensing will produce a spatially coherent distortion of these shapes.

text: In

entity_name: Weak gravitational lensing

text: weak gravitational lensing

text: , the

entity_name: Gravitational lensing formalism

entity_section: Lensing Jacobian

text: Jacobian

text: is mapped out by observing the effect of the shear on the ellipticities of background galaxies.  This effect is purely statistical; the shape of any galaxy will be dominated by its random, unlensed shape, but lensing will produce a spatially coherent distortion of these shapes.

text: The Milky Way galaxy is part of a group of galaxies called the Local Group.

text: The

entity_name: Milky Way

text: Milky Way

text: galaxy is part of a group of galaxies called the

text: Local Group

method: UNH-tfidf-stem

method: UNH-tfidf-ptsim

method: UNH-tfidf-lem

text: The city was initially designed in the shape of the Buddhist Dharma-Chakra (Wheel of Righteousness). The four thurs or mounds on the perimeter of Patan are ascribed around, one at each corner of its cardinal points, which are popularly known as Asoka Stupas. Legend has it that Emperor Asoka (the legendary King of India) visited with his daughter Charumati to Kathmandu in 250 BC and erected five Asoka Stupas, four in the surrounding and one at the middle of the Patan. The size and shape of these stupas seem to breathe their antiquity in a real sense. There are more than 1,200 Buddhist monuments of various shapes and sizes scattered in and around the city.

text: The city was initially designed in the shape of the

entity_name: Buddhism

text: Buddhist

text: Dharma-Chakra (Wheel of Righteousness). The four thurs or mounds on the perimeter of Patan are ascribed around, one at each corner of its cardinal points, which are popularly known as Asoka Stupas. Legend has it that Emperor

entity_name: Ashoka

text: Asoka

text: (the legendary King of

entity_name: India

text: India

text: ) visited with his daughter Charumati to

entity_name: Kathmandu

text: Kathmandu

text: in 250 BC and erected five Asoka Stupas, four in the surrounding and one at the middle of the Patan. The size and shape of these stupas seem to breathe their antiquity in a real sense. There are more than 1,200

text: Buddhist

text: monuments of various shapes and sizes scattered in and around the city.

text: IC 1526  is a spiral galaxy in Pisces

text: IC 1526  is a

entity_name: Spiral galaxy

text: spiral galaxy

text: in

entity_name: Pisces (constellation)

text: Pisces

text: The Milky Way runs through the constellation, featuring prominent objects such as the open cluster NGC 5823 and the planetary nebula NGC 5315. Circinus hosts a spiral galaxy, the Circinus Galaxy, which was discovered in 1977 and is the closest Seyfert galaxy to the Milky Way. The Alpha Circinids (ACI), a meteor shower also discovered in 1977, radiate from this constellation.

text: The

text: Milky Way

text: runs through the constellation, featuring prominent objects such as the

entity_name: Open cluster

text: open cluster

text: NGC 5823

text: and the

entity_name: Planetary nebula

text: planetary nebula

text: NGC 5315

text: . Circinus hosts a

text: spiral galaxy

text: , the

entity_name: Circinus Galaxy

text: Circinus Galaxy

text: , which was discovered in 1977 and is the closest

entity_name: Seyfert galaxy

text: Seyfert galaxy

text: to the Milky Way. The

text: Alpha Circinids

text: (ACI), a

entity_name: Meteor shower

text: meteor shower

text: also discovered in 1977, radiate from this constellation.

text: A galactic quadrant, or quadrant of the Galaxy, is one of four circular sectors in the division of the Milky Way Galaxy.

text: A galactic quadrant, or quadrant of the Galaxy, is one of four

entity_name: Circular sector

text: circular sector

text: s in the division of the

text: Milky Way

text: Galaxy.

text: The Galaxy Tab Pro series refers to the high-end models: the Samsung Galaxy Tab Pro 8.4, Samsung Galaxy Tab Pro 10.1, and Samsung Galaxy Tab Pro 12.2 which are aimed to be the premium model line of Samsung Galaxy tablets together with the Samsung Galaxy Note tablets namely the Samsung Galaxy Note 12.2 which were all announced during the 2014 Consumer Electronics Show in Las Vegas.

text: The Galaxy Tab Pro series refers to the high-end models: the Samsung Galaxy Tab Pro 8.4, Samsung Galaxy Tab Pro 10.1, and Samsung Galaxy Tab Pro 12.2 which are aimed to be the premium model line of Samsung Galaxy tablets together with the

entity_name: Samsung Galaxy Note series

text: Samsung Galaxy Note tablets

text: namely the Samsung Galaxy Note 12.2 which were all announced during the 2014 Consumer Electronics Show in Las Vegas.

method: UvABottomUpChangeOrder

text: To achieve the objectives set out above we have defined a representative sample of galaxies to study. The Herschel data alone does not provide us with a large completely sampled region of sky, but we can use the WISE data to define a near infrared selected sample. As many galaxy properties correlate first with stellar mass, the near infrared, where for most galaxies the bulk of the stellar radiation emerges, provides the best available choice for galaxy selection. There are 3045 galaxies with a WISE 3.4μm detection (SN > 3) within 3000 km s (≈40 Mpc) of the Sun and with a size of D>1 arc min (≈12 kpc at 40 Mpc) – the W sample. Currently within the Herschel archive there are 613 observations of galaxies from this W sample. The intersection of these two samples we will refer to as the WH sample. We will carry out a similar selection for galaxies detected by Planck once the final data becomes available in late 2013 and the intersection of this sample with the WH sample is the WHP sample. The WH sample consists of 80 early type galaxies (T< 0) and 533 late types, 70 of which may be described as star forming irregulars/dwarfs. Also, within the WH sample we have 94 galaxies that have D> 5 arc min and so are resolved in the Herschel bands and lend themselves to full radiative transfer and infrared/mm SED modelling.

text: To achieve the objectives set out above we have defined a representative sample of galaxies to study. The Herschel data alone does not provide us with a large completely sampled region of sky, but we can use the

entity_name: Wide-field Infrared Survey Explorer

text: WISE

text: data to define a near infrared selected sample. As many galaxy properties correlate first with stellar mass, the near infrared, where for most galaxies the bulk of the stellar radiation emerges, provides the best available choice for galaxy selection. There are 3045 galaxies with a WISE 3.4μm detection (SN > 3) within 3000 km s (≈40 Mpc) of the Sun and with a size of D>1 arc min (≈12 kpc at 40 Mpc) – the W sample. Currently within the Herschel archive there are 613 observations of galaxies from this W sample. The intersection of these two samples we will refer to as the WH sample. We will carry out a similar selection for galaxies detected by Planck once the final data becomes available in late 2013 and the intersection of this sample with the WH sample is the WHP sample. The WH sample consists of 80 early type galaxies (T< 0) and 533 late types, 70 of which may be described as star forming irregulars/dwarfs. Also, within the WH sample we have 94 galaxies that have D> 5 arc min and so are resolved in the Herschel bands and lend themselves to full radiative transfer and infrared/mm SED modelling.

text: Since 2006, a series of massive clusters have been identified bear the base of the Crux-Scutum Arm of the galaxy, each containing multiple red supergiants.  RSGC1 contains at least 12 red supergiants, RSGC2 (also known as Stephenson 2) contains at least 26, RSGC3 contains at least 8, and RSGC4 (also known as Alicante 8) contains at least 8.  A total of 80 confirmed red supergiants have been identified within a small area of the sky in the direction of these clusters.  These four clusters appear to be part of a massive burst of star formation 10-20 million years ago at the near end of the bar at the centre of the galaxy.  Similar massive clusters have been found near the far end of the galactic bar, but not such large numbers of red supergiants.

text: Since 2006, a series of massive clusters have been identified bear the base of the

entity_name: Scutum–Centaurus Arm

text: Crux-Scutum Arm

text: of the galaxy, each containing multiple red supergiants.

text: contains at least 12 red supergiants, RSGC2 (also known as

entity_name: Stephenson 2

text: Stephenson 2

text: ) contains at least 26,

text: contains at least 8, and RSGC4 (also known as

entity_name: Alicante 8

text: Alicante 8

text: ) contains at least 8.  A total of 80 confirmed red supergiants have been identified within a small area of the sky in the direction of these clusters.  These four clusters appear to be part of a massive burst of star formation 10-20 million years ago at the near end of the bar at the centre of the galaxy.  Similar massive clusters have been found near the far end of the galactic bar, but not such large numbers of red supergiants.

text: The Local Group is the galaxy group that includes the Milky Way. The Local Group comprises more than 54 galaxies, most of them dwarf galaxies. Its gravitational center is located somewhere between the Milky Way and the Andromeda Galaxy. The Local Group covers a diameter of  (about 10 meters) and has a binary (dumbbell)distribution. The group itself is a part of the larger Virgo Supercluster, which in turn may be a part of the Laniakea Supercluster.

text: The Local Group is the

text: galaxy group

text: that includes the

text: Milky Way

text: . The Local Group comprises more than 54 galaxies, most of them

entity_name: Dwarf galaxy

text: dwarf galaxies

text: . Its gravitational center is located somewhere between the Milky Way and the

entity_name: Andromeda Galaxy

text: Andromeda Galaxy

text: . The Local Group covers a diameter of  (about 10 meters) and has a binary (dumbbell)distribution. The group itself is a part of the larger

entity_name: Virgo Supercluster

text: Virgo Supercluster

text: , which in turn may be a part of the

entity_name: Laniakea Supercluster

text: Laniakea Supercluster

text: NGC 4618 is a distorted barred dwarf galaxy in the constellation Canes Venatici.  The galaxy is formally classified as a Sm galaxy, which means that its structure vaguely resembles the structure of spiral galaxies.  The galaxy is sometimes referred to as a Magellanic spiral because of its resemblance to the Magellanic clouds.

text: NGC 4618 is a distorted barred

text: dwarf galaxy

text: in the

entity_name: Constellation

text: constellation

entity_name: Canes Venatici

text: Canes Venatici

text: .  The galaxy is formally classified as a

entity_name: Galaxy morphological classification

text: Sm

text: galaxy, which means that its structure vaguely resembles the structure of

text: spiral galaxies

text: .  The galaxy is sometimes referred to as a

entity_name: Magellanic spiral

text: Magellanic spiral

text: because of its resemblance to the

entity_name: Magellanic Clouds

text: Magellanic clouds

text: The Milky Way is the galaxy that contains our Solar System. Its name "milky" is derived from its appearance as a dim glowing band arching across the night sky whose individual stars cannot be distinguished by the naked eye. The term "Milky Way" is a translation of the Latin via lactea, from the Greek γαλαξίας κύκλος (, "milky circle"). From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis, observations by Edwin Hubble showed that the Milky Way is just one of many galaxies.  Subsequent sensitive observations such as the Hubble telescope's Ultra Deep Field revealed a myriad of faint galaxies, which led to an estimate that the observable universe contained about 200 billion galaxies.  A 2016 study estimated that the observable universe contained ten times that number or 2 trillion galaxies.

text: The Milky Way is the

text: galaxy

text: that contains our

entity_name: Solar System

text: Solar System

text: . Its name "milky" is derived from its appearance as a dim glowing band arching across the night sky whose individual stars cannot be distinguished by the naked eye. The term "Milky Way" is a translation of the

entity_name: Latin

text: Latin

text: via lactea, from the

entity_name: Ancient Greek

text: Greek

text: γαλαξίας κύκλος (, "milky circle"). From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within.

entity_name: Galileo Galilei

text: Galileo Galilei

text: first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the

entity_name: Universe

text: Universe

text: . Following the 1920

entity_name: Great Debate (astronomy)

text: Great Debate

text: between the astronomers

text: Harlow Shapley

text: and

text: Heber Curtis

text: , observations by

text: Edwin Hubble

text: showed that the Milky Way is just one of many galaxies.  Subsequent sensitive observations such as the Hubble telescope's

text: Ultra Deep Field

text: revealed a myriad of faint galaxies, which led to an estimate that the

text: observable universe

text: contained about 200 billion galaxies.  A 2016 study estimated that the observable universe contained ten times that number or 2 trillion galaxies.

text: It is thought that Red Spirals are galaxies in the process of transition from young to old. They are more massive than blue spirals and are found on the outskirts of large clusters of galaxies. Chris Lintott stated: "We think what we’re seeing is galaxies that have been gently strangled, so to speak, where somehow the gas supply for star formation has been cut off, but that they’ve been strangled so gently that the arms are still there." The cause might be the Red Spiral's gentle interaction with a galaxy cluster. He further explained: "The kind of thing we’re imagining [is that] as the galaxy moves into a denser environment, there’s lot of gas in clusters as well as galaxies, and it’s possible the gas from the galaxy just gets stripped off by the denser medium it’s plowing into."

text: It is thought that Red Spirals are galaxies in the process of transition from young to old. They are more massive than blue spirals and are found on the outskirts of large

text: clusters

text: of galaxies. Chris Lintott stated: "We think what we’re seeing is galaxies that have been gently strangled, so to speak, where somehow the gas supply for star formation has been cut off, but that they’ve been strangled so gently that the arms are still there." The cause might be the Red Spiral's gentle interaction with a galaxy cluster. He further explained: "The kind of thing we’re imagining [is that] as the galaxy moves into a denser environment, there’s lot of gas in clusters as well as galaxies, and it’s possible the gas from the galaxy just gets stripped off by the denser medium it’s plowing into."

text: In 2005, astronomers discovered a completely new type of star cluster in the Andromeda Galaxy, which is, in several ways, very similar to globular clusters. The new-found clusters contain hundreds of thousands of stars, a similar number to that found in globular clusters. The clusters share other characteristics with globular clusters such as stellar populations and metallicity. What distinguishes them from the globular clusters is that they are much larger – several hundred light-years across – and hundreds of times less dense. The distances between the stars are, therefore, much greater within the newly discovered extended clusters. Parametrically, these clusters lie somewhere between a globular cluster and a dwarf spheroidal galaxy.

text: In 2005, astronomers discovered a completely new type of star cluster in the Andromeda Galaxy, which is, in several ways, very similar to globular clusters. The new-found clusters contain hundreds of thousands of stars, a similar number to that found in globular clusters. The clusters share other characteristics with globular clusters such as stellar populations and metallicity. What distinguishes them from the globular clusters is that they are much larger – several hundred light-years across – and hundreds of times less dense. The distances between the stars are, therefore, much greater within the newly discovered extended clusters. Parametrically, these clusters lie somewhere between a globular cluster and a

text: dwarf spheroidal galaxy

text: Spiral galaxies have central bar-shaped structures composed of stars. These galaxies are called 'barred spirals' and have been investigated by Galaxy Zoo in several studies. It is unclear why some spiral galaxies have bars and some do not. Galaxy Zoo research has shown that red spirals are about twice as likely to host bars as blue spirals. These colours are significant. Blue galaxies get their hue from the hot young stars they contain, implying that they are forming stars in large numbers. In red galaxies, this star formation has stopped, leaving behind the cooler, long-lived stars that give them their red colour.

text: Spiral galaxies

text: have central bar-shaped structures composed of stars. These galaxies are called

text: 'barred spirals'

text: and have been investigated by Galaxy Zoo in several studies. It is unclear why some spiral galaxies have bars and some do not. Galaxy Zoo research has shown that red spirals are about twice as likely to host bars as blue spirals. These colours are significant. Blue galaxies get their hue from the hot young stars they contain, implying that they are forming stars in large numbers. In red galaxies, this star formation has stopped, leaving behind the cooler, long-lived stars that give them their red colour.

text: The Whirlpool Galaxy, also known as Messier 51a, M51a, or NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus in the constellation Canes Venatici. It was the first galaxy to be classified as a spiral galaxy. Recently it was estimated to be 23 ± 4 million light-years from the Milky Way, but different methods yield distances between 15 and 35 million light-years. Messier 51 is one of the best known galaxies in the sky.The galaxy and its companion, NGC 5195, are easily observed by amateur astronomers, and the two galaxies may even be seen with binoculars. The Whirlpool Galaxy is also a popular target for professional astronomers, who study it to further understand galaxy structure (particularly structure associated with the spiral arms) and galaxy interactions.

text: The Whirlpool Galaxy, also known as

text: Messier

text: 51a, M51a, or NGC 5194, is an

text: interacting

text: grand-design

text: spiral galaxy

text: with a

text: Seyfert 2

text: active galactic nucleus

text: in the

text: constellation

text: Canes Venatici

text: . It was the first galaxy to be classified as a spiral galaxy. Recently it was estimated to be 23 ± 4 million

text: light-year

text: s from the

text: Milky Way

text: , but different methods yield distances between 15 and 35 million light-years. Messier 51 is one of the best known galaxies in the sky.The galaxy and its companion,

text: NGC 5195

text: , are easily observed by

text: amateur astronomers

text: , and the two galaxies may even be seen with

text: binoculars

text: . The Whirlpool Galaxy is also a popular target for professional astronomers, who study it to further understand galaxy structure (particularly structure associated with the

text: spiral arms

text: ) and galaxy interactions.

text: A spiral galaxy is a type of galaxy characterized by a central bulge of old Population II stars surrounded by a rotating disc of younger Population I stars. A spiral galaxy maintains its spirals arms due to density wave theory.

text: A

text: spiral galaxy

text: is a type of

text: galaxy

text: characterized by a central

text: bulge

text: of old

text: Population II

text: star

text: s surrounded by a rotating disc of younger

text: Population I

text: stars. A spiral galaxy maintains its

text: spirals arms

text: due to

text: density wave theory

text: Type Sm and Im galaxies have also been categorized as irregular galaxies with some structure (type Irr-1). Sm galaxies are typically disrupted and asymmetric. dSm galaxies are dwarf spiral galaxies or dwarf irregular galaxies, depending on categorization scheme.

text: Type Sm and Im galaxies have also been categorized as

text: irregular galaxies

text: with some structure (type Irr-1). Sm galaxies are typically disrupted and asymmetric. dSm galaxies are

text: dwarf spiral galaxies

text: or

text: dwarf irregular galaxies

text: , depending on categorization scheme.

text: NGC 5247 is a face-on unbarred spiral galaxy located some 60 million light years away in the constellation Virgo. It most likely belongs to the Virgo Supercluster of galaxies; the same supercluster that hosts the Milky Way galaxy. This is a grand design spiral galaxy that displays no indications of distortion caused by interaction with other galaxies. It has two spiral arms that bifurcate after wrapping half way around the nucleus. The disk is estimated to be  in thickness and it is inclined by roughly 28° to the line of sight.

text: NGC 5247 is a face-on

text: unbarred spiral galaxy

text: located some 60 million

text: light year

text: s away in the

text: constellation

text: Virgo

text: . It most likely belongs to the

text: Virgo Supercluster

text: of galaxies; the same

text: supercluster

text: that hosts the

text: Milky Way

text: galaxy. This is a

text: grand design spiral galaxy

text: that displays no indications of distortion caused by

text: interaction

text: with other galaxies. It has two spiral arms that bifurcate after wrapping half way around the nucleus. The disk is estimated to be  in thickness and it is inclined by roughly 28° to the line of sight.

text: Andromeda Galaxy was formed roughly 10 billion years ago from the collision and subsequent merger of smaller protogalaxies.This violent collision formed most of the galaxy's (metal-rich) galactic halo and extended disk. During this epoch, star formation would have been very high, to the point of becoming a luminous infrared galaxy for roughly 100 million years. Andromeda and the Triangulum Galaxy had a very close passage 2–4 billion years ago. This event produced high levels of star formation across the Andromeda Galaxy's disk – even some globular clusters – and disturbed M33's outer disk.

text: Andromeda Galaxy was formed roughly 10 billion years ago from the collision and subsequent merger of smaller

text: protogalaxies

text: .This violent collision formed most of the galaxy's (metal-rich)

text: galactic halo

text: and extended disk. During this epoch,

text: star formation

text: would have been

text: very high

text: , to the point of becoming a

text: luminous infrared galaxy

text: for roughly 100 million years. Andromeda and the

text: Triangulum Galaxy

text: had a very close passage 2–4 billion years ago. This event produced high levels of star formation across the Andromeda Galaxy's disk – even some globular clusters – and disturbed M33's outer disk.

text: of elliptical galaxies, first noted by the astronomers Sandra M. Faber and Robert Earl Jackson in 1976.    The original relation can be expressed mathematically as:

text: of

text: elliptical galaxies

text: , first noted by the astronomers

text: Sandra M. Faber

text: and

text: Robert Earl Jackson

text: in 1976.    The original relation can be expressed mathematically as:

text: Kapteyn's Star is distinctive in a number of other regards: it has a high radial velocity, orbits the Milky Way retrograde, and is the nearest known halo star to the Sun. It is a member of a moving group of stars that share a common trajectory through space, named the Kapteyn moving group. Based upon their element abundances, these stars may once have been members of Omega Centauri, a globular cluster that is thought to be the remnant of a dwarf galaxy that merged with the Milky Way. During this process, the stars in the group, including Kapteyn's Star, may have been stripped away as tidal debris.

text: Kapteyn's Star is distinctive in a number of other regards: it has a high radial velocity, orbits the

text: Milky Way

text: retrograde

text: , and is the nearest known

text: halo

text: star to the Sun. It is a member of a

text: moving group

text: of stars that share a common trajectory through space, named the Kapteyn moving group. Based upon their

text: element abundances

text: , these stars may once have been members of

text: Omega Centauri

text: , a

text: globular cluster

text: that is thought to be the remnant of a

text: dwarf galaxy

text: that merged with the Milky Way. During this process, the stars in the group, including Kapteyn's Star, may have been stripped away as tidal debris.

text: Most elliptical galaxies are composed of older, low-mass stars, with a sparse interstellar medium and minimal star formation activity, and they tend to be surrounded by large numbers of globular clusters. Elliptical galaxies are believed to make up approximately 10–15% of galaxies in the Virgo Supercluster, and they are not the dominant type of galaxy in the universe overall. They are preferentially found close to the centers of galaxy clusters. Elliptical galaxies are (together with lenticular galaxies) also called "early-type" galaxies (ETG), due to their location in the Hubble sequence, and are found to be less common in the early Universe.

text: Most elliptical galaxies are composed of older,

text: low-mass stars

text: , with a sparse

text: interstellar medium

text: and minimal

text: star formation

text: activity, and they tend to be surrounded by large numbers of

text: globular cluster

text: s. Elliptical galaxies are believed to make up approximately 10–15% of galaxies in the

text: Virgo Supercluster

text: , and they are not the dominant type of galaxy in the universe overall. They are preferentially found close to the centers of

text: galaxy cluster

text: s. Elliptical galaxies are (together with

text: lenticular galaxies

text: ) also called "early-type" galaxies (ETG), due to their location in the

text: Hubble sequence

text: , and are found to be less common in the early

text: Universe

text: Although the UKST was originally used to take photographs of the sky, traditional photographic glass (and film) became largely superseded by large electronic CCD detectors in the late 1990s, and after 2000 the UKST was used mostly for multi-object spectroscopy with the 6 degree Field (6dF) instrument. 6dF uses a robot to position up to 150 optical fibres on a metal plate mounted at the focal plane of the UKST, which then carry light from the targets to a spectrograph which sits on the floor of the dome. The 6dF Galaxy Survey (6dFGS), a redshift survey of 120,000 infrared-selected galaxies was completed in 2005, and from 2003-2013 the UKST then carried out the RAdial Velocity Experiment (RAVE) to measure the radial velocities and metallicities of around to 0.5 million stars in the Milky Way Galaxy.

text: Although the UKST was originally used to take

text: photographs

text: of the sky, traditional photographic glass (and film) became largely superseded by large electronic

text: CCD

text: detectors in the late 1990s, and after 2000 the UKST was used mostly for multi-object

text: spectroscopy

text: with the 6 degree Field (6dF) instrument. 6dF uses a robot to position up to 150

text: optical fibres

text: on a metal plate mounted at the

text: focal plane

text: of the UKST, which then carry light from the targets to a

text: spectrograph

text: which sits on the floor of the dome. The

text: 6dF Galaxy Survey

text: (6dFGS), a

text: redshift survey

text: of 120,000

text: infrared

text: -selected

text: galaxies

text: was completed in 2005, and from 2003-2013 the UKST then carried out the

text: RAdial Velocity Experiment

text: (RAVE) to measure the

text: radial velocities

text: and

text: metallicities

text: of around to 0.5 million stars in the

text: Milky Way Galaxy

text: In SAIS the game players explore a "plausibly implausible" (fictional) region of the Milky Way galaxy called The Purple Void.

text: In SAIS the game players explore a "plausibly implausible" (fictional) region of the

text: Milky Way

text: galaxy

text: called The Purple Void.

text: Because galaxy-size density fluctuations get washed out by free-streaming, "hot" dark matter implies that the first objects that can form are huge supercluster-size pancakes, which then fragment into galaxies. Deep-field observations show instead that galaxies formed first, followed by clusters and superclusters as galaxies clump together.

text: Because galaxy-size density fluctuations get washed out by free-streaming, "hot" dark matter implies that the first objects that can form are huge supercluster-size pancakes, which then fragment into galaxies.

text: Deep-field observations

text: show instead that galaxies formed first, followed by clusters and

text: superclusters

text: as galaxies clump together.

text: The formation of globular clusters remains a poorly understood phenomenon and it remains uncertain whether the stars in a globular cluster form in a single generation or are spawned across multiple generations over a period of several hundred million years. In many globular clusters, most of the stars are at approximately the same stage in stellar evolution, suggesting that they formed at about the same time. However, the star formation history varies from cluster to cluster, with some clusters showing distinct populations of stars. An example of this is the globular clusters in the Large Magellanic Cloud (LMC) that exhibit a bimodal population. During their youth, these LMC clusters may have encountered giant molecular clouds that triggered a second round of star formation. This star-forming period is relatively brief, compared to the age of many globular clusters.It has also been proposed that the reason for this multiplicity in stellar populations could have a dynamical origin. In the Antennae galaxy, for example, the Hubble Space Telescope has observed clusters of clusters, regions in the galaxy that span hundreds of parsecs, where many of the clusters will eventually collide and merge. Many of them present a significant range in ages, hence possibly metallicities, and their merger could plausibly lead to clusters with a bimodal or even multiple distribution of populations.

text: The formation of globular clusters remains a poorly understood phenomenon and it remains uncertain whether the stars in a globular cluster form in a single generation or are spawned across multiple generations over a period of several hundred million years. In many globular clusters, most of the stars are at approximately the same stage in

text: stellar evolution

text: , suggesting that they formed at about the same time. However, the star formation history varies from cluster to cluster, with some clusters showing distinct populations of stars. An example of this is the globular clusters in the

text: Large Magellanic Cloud

text: (LMC) that exhibit a bimodal population. During their youth, these LMC clusters may have encountered

text: giant molecular cloud

text: s that triggered a second round of star formation. This star-forming period is relatively brief, compared to the age of many globular clusters.It has also been proposed that the reason for this multiplicity in stellar populations could have a dynamical origin. In the

text: Antennae galaxy

text: , for example, the Hubble Space Telescope has observed clusters of clusters, regions in the galaxy that span hundreds of parsecs, where many of the clusters will eventually collide and merge. Many of them present a significant range in ages, hence possibly

text: metallicities

text: , and their merger could plausibly lead to clusters with a bimodal or even multiple distribution of populations.

text: Spiral galaxies consist of five distinct components:

text: In 2012, she published her findings from a study into the evolution of stars within galaxies which themselves are members of galaxy clusters, using the Gemini North Observatory in Hawaii.  The research found that a galaxy's position within the galactic cluster affected stellar evolution within that galaxy: the closer a galaxy is to the center of a cluster, the sooner it stops forming new stars. The interpretation of this is that near the centre of the cluster, the large number of close galactic neighbours influence each other through gravitation to produce a sea of hot gas, and that hot gas seems to be the limiting factor that constrains new star formation. Mergers of galaxies also play a part: her forecasts of how our own Milky Way galaxy will merge with the Andromeda Galaxy and the two smaller Magellanic Cloud galaxies in several billion years have prompted further new studies into how that will affect the rates of star formation locally.

text: In 2012, she published her findings from a study into the evolution of stars within galaxies which themselves are members of galaxy clusters, using the

text: Gemini North

text: Observatory in

text: Hawaii

text: .  The research found that a galaxy's position within the galactic cluster affected stellar evolution within that galaxy: the closer a galaxy is to the center of a cluster, the sooner it stops forming new stars. The interpretation of this is that near the centre of the cluster, the large number of close galactic neighbours influence each other through gravitation to produce a sea of hot gas, and that hot gas seems to be the limiting factor that constrains new star formation. Mergers of galaxies also play a part: her forecasts of how our own Milky Way galaxy will merge with the Andromeda Galaxy and the two smaller Magellanic Cloud galaxies in several billion years have prompted further new studies into how that will affect the rates of star formation locally.

text: Galaxies come in three main types: ellipticals, spirals, and irregulars. A slightly more extensive description of galaxy types based on their appearance is given by the Hubble sequence. Since the Hubble sequence is entirely based upon visual morphological type(shape), it may miss certain important characteristics of galaxies such as star formation rate in starburst galaxies and activity in the cores of active galaxies.

text: Galaxies come in three main types: ellipticals, spirals, and irregulars. A slightly more extensive description of galaxy types based on their appearance is given by the

text: Hubble sequence

text: . Since the Hubble sequence is entirely based upon visual morphological type(shape), it may miss certain important characteristics of galaxies such as

text: star formation

text: rate in

text: starburst galaxies

text: and activity in the cores of

text: active galaxies

text: A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in approximately two-thirds of all spiral galaxies. Bars generally affect both the motions of stars and interstellar gas within spiral galaxies and can affect spiral arms as well. The Milky Way Galaxy, where our own Solar System is located, is classified as a barred spiral galaxy.

text: A barred spiral galaxy is a

text: spiral galaxy

text: with a central bar-shaped structure composed of

text: star

text: s. Bars are found in approximately two-thirds of all spiral galaxies. Bars generally affect both the motions of stars and

text: interstellar gas

text: within spiral galaxies and can affect

text: spiral arm

text: s as well. The

text: Milky Way Galaxy

text: , where our own

text: Solar System

text: is located, is classified as a barred spiral galaxy.

text: Our own Galaxy, the Milky Way, is contained in the Local Group of more than 40 galaxies.

text: Our own Galaxy, the

text: Milky Way

text: , is contained in the

text: Local Group

text: of more than 40 galaxies.

text: As the name suggests, an elliptical galaxy has the cross-sectional shape of an ellipse. The stars move along random orbits with no preferred direction. These galaxies contain little or no interstellar dust, few star-forming regions, and generally older stars. Elliptical galaxies are more commonly found at the core of galactic clusters, and may have been formed through mergers of large galaxies.

text: As the name suggests, an elliptical galaxy has the cross-sectional shape of an

text: ellipse

text: . The stars move along

text: random

text: orbits with no preferred direction. These galaxies contain little or no interstellar dust, few star-forming regions, and generally older stars. Elliptical galaxies are more commonly found at the core of galactic clusters, and may have been formed through mergers of large galaxies.

text: Not only was BX442 revealed to be a genuine spiral galaxy, but part of a sub-class known as 'grand-design' spirals.  Most spiral galaxies have subtler features and the arms of the spiral are not necessarily well-defined. A grand design spiral galaxy has very clearly well-formed and distinct arms that significantly stretch out around the galaxy center. Of all spiral galaxies, only about 10% of them are classified as a grand design spiral galaxy.

text: In the French astronomer Gérard de Vaucouleurs' revised Hubble Sandage (VRHS) system of galaxy morphological classification, the Triangulum galaxy is classified as type SA(s)cd. The S prefix indicates that it is a disk-shaped galaxy with prominent arms of gas and dust that spiral out from the nucleus—what is commonly known as a spiral galaxy. The A is assigned when the galactic nucleus lacks a bar-shaped structure, in contrast to SB class barred spiral galaxies. American astronomer Allan Sandage's "(s)" notation is used when the spiral arms emerge directly from the nucleus or central bar, rather than from an inner ring as with an (r)-type galaxy. Finally, the cd suffix represents a stage along the spiral sequence that describes the openness of the arms. A rating of cd indicates relatively loosely wound arms.

text: In the French astronomer

text: Gérard de Vaucouleurs

text: ' revised Hubble Sandage (VRHS) system of

text: galaxy morphological classification

text: , the Triangulum galaxy is classified as type SA(s)cd. The S prefix indicates that it is a disk-shaped galaxy with prominent arms of gas and dust that spiral out from the nucleus—what is commonly known as a

text: spiral galaxy

text: . The A is assigned when the galactic nucleus lacks a bar-shaped structure, in contrast to SB class

text: barred spiral galaxies

text: . American astronomer

text: Allan Sandage

text: 's "(s)" notation is used when the spiral arms emerge directly from the nucleus or central bar, rather than from an inner ring as with an (r)-type galaxy. Finally, the cd suffix represents a stage along the spiral sequence that describes the openness of the arms. A rating of cd indicates relatively loosely wound arms.

text: The strength of diffusion damping is calculated by a mathematical expression for the damping factor, which figures into the Boltzmann equation, an equation which describes the amplitude of perturbations in the CMB. The strength of the diffusion damping is chiefly governed by the distance photons travel before being scattered (diffusion length). What affect the diffusion length are primarily the properties of the plasma in question: different sorts of plasma may experience different sorts of diffusion damping. The evolution of a plasma may also affect the damping process. The scale on which diffusion damping works is called the Silk scale and its value corresponds to the size of galaxies of the present day. The mass contained within the Silk scale is called the Silk mass and it corresponds to the mass of the galaxies.

text: The strength of diffusion damping is calculated by a mathematical expression for the damping factor, which figures into the

text: Boltzmann equation

text: , an equation which describes the amplitude of perturbations in the CMB. The strength of the diffusion damping is chiefly governed by the distance photons travel before being scattered (diffusion length). What affect the diffusion length are primarily the properties of the plasma in question: different sorts of plasma may experience different sorts of diffusion damping. The evolution of a plasma may also affect the damping process. The scale on which diffusion damping works is called the Silk scale and its value corresponds to the size of galaxies of the present day. The mass contained within the Silk scale is called the Silk mass and it corresponds to the mass of the galaxies.

text: The theory accounts for the rotation curves of spiral galaxies, correctly reproducing the Tully-Fisher law.

text: The theory accounts for the rotation curves of spiral galaxies, correctly reproducing the

text: Tully-Fisher law

text: The Sculptor Wall is a superstructure of galaxies ("wall of galaxies") relatively near to the Milky Way Galaxy (redshift of approximately z=0.03), also known as the Sculptor superclusters.

text: The Sculptor Wall is a superstructure of

text: galaxies

text: "wall of galaxies"

text: ) relatively near to the

text: Milky Way Galaxy

text: redshift

text: of approximately z=0.03), also known as the Sculptor superclusters.

text: Hepzibah is a brilliant natural athlete and acrobat, and skilled hand-to-hand combatant, trained in various forms of armed and unarmed combat known in the Shi'ar galaxy. She is also an expert marksman, and is knowledgeable in the operation of a wide variety of ship-sized weaponry. She is often armed with Shi'ar energy guns.

text: The cluster is a fairly heterogeneous mixture of spirals and ellipticals. , it is believed that the spirals of the cluster are distributed in an oblong prolate filament, approximately four times as long as it is wide, stretching along the line of sight from the Milky Way. The elliptical galaxies are more centrally concentrated than the spiral galaxies.

text: The cluster is a fairly

text: heterogeneous

text: mixture of spirals and ellipticals. , it is believed that the spirals of the cluster are distributed in an oblong

text: prolate

text: filament, approximately four times as long as it is wide, stretching along the line of sight from the

text: Milky Way

text: . The elliptical galaxies are more centrally concentrated than the spiral galaxies.

text: The Sculptor Galaxy (NGC 253) and a few other galaxies form a gravitationally-bound core in the center of this group.  A few other galaxies at the periphery may be associated with the group but may not be gravitationally bound.  Because most of the galaxies in this group are actually weakly gravitationally bound, the group may also be described as a filament. It is considered to be at an early stage of evolution in which galaxies are still falling into the group along filamentary structures.

text: The

text: Sculptor Galaxy

text: (NGC 253) and a few other galaxies form a gravitationally-bound core in the center of this group.  A few other galaxies at the periphery may be associated with the group but may not be gravitationally bound.  Because most of the galaxies in this group are actually weakly gravitationally bound, the group may also be described as a

text: filament

text: . It is considered to be at an early stage of evolution in which galaxies are still falling into the group along filamentary structures.

text: DDO 216 (also known as Pegasus Dwarf Irregular Galaxy, PGC 71538 or UGC 12613) is a dwarf irregular galaxy located in the constellation Pegasus.

text: DDO 216

text: (also known as

text: Pegasus

text: Dwarf Irregular

text: Galaxy

text: PGC

text: 71538 or

text: UGC

text: 12613) is a

text: dwarf irregular galaxy

text: located in the

text: constellation

text: Pegasus

text: Leo A (also known as Leo III) is an irregular  galaxy that is part of the Local Group. It lies 2.6 million light-years from Earth, and was discovered by Fritz Zwicky in 1942. The estimated mass of this galaxy is  solar masses, with at least 80% consisting of an unknown dark matter. It is one of the most isolated galaxies in the Local Group and shows no indications of an interaction or merger for several billion years. However, Leo A is nearly unique among irregular galaxies in that more than 90% of its stars formed more recently than 8 billion years ago, suggesting a rather unusual evolutionary history. The presence of RR Lyrae variables shows that the galaxy has an old stellar population that is up to 10 billion years in age.

text: Leo A (also known as Leo III) is an

text: irregular

text: galaxy

text: that is part of the

text: Local Group

text: . It lies

text: million

text: light-year

text: s from

text: Earth

text: , and was discovered by

text: Fritz Zwicky

text: in 1942. The estimated mass of this galaxy is

text: solar mass

text: es, with at least 80% consisting of an unknown

text: dark matter

text: . It is one of the most isolated galaxies in the Local Group and shows no indications of an interaction or merger for several billion years. However, Leo A is nearly unique among irregular galaxies in that more than 90% of its stars formed more recently than 8 billion years ago, suggesting a rather unusual evolutionary history. The presence of

text: RR Lyrae variable

text: s shows that the galaxy has an old stellar population that is up to 10 billion years in age.

text: Noah Brosch was fascinated very early in his scientific career by the unique appearance of Hoag's Object, a very round ring galaxy and published a number of papers on this topic. Together with his student Ido Finkelman, and with colleagues from Russia and the Netherlands, they showed that the visible ring is part of an even larger ring of neutral hydrogen and proposed that the ring represents material accreted by the elliptical core at least one billion years ago. Hoag's Object would, therefore, represent a much undisturbed galaxy .

text: Noah Brosch was fascinated very early in his scientific career by the unique appearance of

text: Hoag's Object

text: , a very round ring galaxy and published a number of papers on this topic. Together with his student Ido Finkelman, and with colleagues from Russia and the Netherlands, they showed that the visible ring is part of an even larger ring of neutral hydrogen and proposed that the ring represents material accreted by the elliptical core at least one billion years ago.

text: Hoag's Object

text: would, therefore, represent a much undisturbed galaxy .

text: BX442 (Q2343-BX442) is a grand design spiral galaxy of type Sc. It has a companion dwarf galaxy. It is the most distant known grand design spiral galaxy in the universe, with a redshift of z=2.1765 ± 0.0001.Although commonly referred to as the oldest known grand design spiral galaxy in the universe,it is more accurately the earliest such galaxy known to exist in the universe, with a lookback time (the difference between the age of the universe now and the age of the universe at the time light left the galaxy) of 10.7 billion years in the concordance cosmology.  This time estimate means that structure seen in BX442 developed roughly 3 billion years after the Big Bang, and is 10 kiloparsecs (30,000 ly) in diameter.

text: BX442 (Q2343-BX442) is a

text: grand design

text: spiral

text: galaxy

text: of type

text: Sc

text: . It has a companion

text: dwarf galaxy

text: . It is the most distant known

text: grand design spiral galaxy

text: in the universe, with a redshift of z=2.1765 ± 0.0001.Although commonly referred to as the oldest known

text: grand design spiral galaxy

text: in the universe,it is more accurately the earliest such galaxy known to exist in the universe, with a lookback time (the difference between the age of the universe now and the age of the universe at the time light left the galaxy) of 10.7 billion years in the

text: concordance cosmology

text: .  This time estimate means that structure seen in BX442 developed roughly 3 billion years after the Big Bang, and is 10 kiloparsecs (30,000 ly) in diameter.

text: The Magellanic Cloud galaxies were once classified as irregular galaxies. The Large Magellanic Cloud has since been re-classified as type SBm  a type of barred spiral galaxy, the barred Magellanic spiral type. The Small Magellanic Cloud remains classified as an irregular galaxy of type Im under current Galaxy morphological classification, although it does contain a bar structure.

text: The

text: Magellanic Cloud galaxies

text: were once classified as irregular galaxies. The

text: Large Magellanic Cloud

text: has since been re-classified as type SBm  a type of

text: barred spiral galaxy

text: , the barred

text: Magellanic spiral

text: type. The

text: Small Magellanic Cloud

text: remains classified as an irregular galaxy of type Im under current

text: Galaxy morphological classification

text: , although it does contain a

text: bar structure

text: How these clusters are formed is not yet known, but their formation might well be related to that of globular clusters. Why M31 has such clusters, while the Milky Way has not, is not yet known. It is also unknown if any other galaxy contains this kind of clusters, but it would be very unlikely that M31 is the sole galaxy with extended clusters.

text: The mall was developed by Jacobs, Visconsi, and Jacobs Company of Cleveland, Ohio. Construction began September 18, 1970. Originally, the mall contained eight water pools and sunken lounge areas. Artists Clarence Van Duzer and Joseph McDonnell were commissioned to create art work for the mall. McDonnell created four sculptures, including a 3,000 pound metal yellow rhinoceros with red polka dots made of half-inch steel plates. Another was a 35'x22' chandelier-like work suspended above one of the entryways. The chandelier was multi-colored and according to McDonnell, was inspired by a game of pick-up sticks and designed to resemble "a galaxy of light" from outside the center. Van Duzen was responsible for the large central area with its  ceiling and four contemporary pillars. In the center was a large three-level pool with waterfalls, a  fountain, and flashing lights, all synchronized to music. The main entrance was flanked by sculpted stone blocks in relief with irregular shapes and sizes. All the water sculptures and sunken lounge areas were removed in the late 1980s and the main entrance was redesigned, with the addition of a food court.

text: The mall was developed by

text: Jacobs, Visconsi, and Jacobs Company

text: of

text: Cleveland, Ohio

text: . Construction began September 18, 1970. Originally, the mall contained eight water pools and sunken lounge areas. Artists Clarence Van Duzer and Joseph McDonnell were commissioned to create art work for the mall. McDonnell created four sculptures, including a 3,000 pound metal yellow

text: rhinoceros

text: with red polka dots made of half-inch steel plates. Another was a 35'x22'

text: chandelier

text: -like work suspended above one of the entryways. The chandelier was multi-colored and according to McDonnell, was inspired by a game of

text: pick-up sticks

text: and designed to resemble "a

text: galaxy

text: of light" from outside the center. Van Duzen was responsible for the large central area with its  ceiling and four contemporary pillars. In the center was a large three-level pool with waterfalls, a  fountain, and flashing lights, all synchronized to music. The main entrance was flanked by sculpted stone blocks in relief with irregular shapes and sizes. All the water sculptures and sunken lounge areas were removed in the late 1980s and the main entrance was redesigned, with the addition of a

text: food court

text: John Drury Clark was the first to present a spiral with an oval outline. His design was used as a vividly coloured two-page illustration in Life magazine for 16 May 1949. In 1951, Edgar Longman, an artist, not a chemist, painted a large mural, adapting the Life image  by making the shape elliptical and tilting it to produce a dynamic effect. This inspired Stewart, then 12 years old, with a love of chemistry. Having just read Fred Hoyle's book The Nature of the Universe, he had the idea that Longman's design resembled a spiral galaxy. He returned to the idea many years later and published a first version of his "galaxy" in November 2004. His design seeks to express the link between the utterly minute world of atoms and the vastness of the stars, in the interior of which the elements were forged, as Hoyle was the first to demonstrate in detail.

text: John Drury Clark

text: was the first to present a spiral with an oval outline. His design was used as a vividly coloured two-page illustration in Life magazine for 16 May 1949. In 1951,

text: Edgar Longman

text: , an artist, not a chemist, painted a large mural, adapting the Life image  by making the shape

text: elliptical

text: and tilting it to produce a dynamic effect. This inspired Stewart, then 12 years old, with a love of chemistry. Having just read

text: Fred Hoyle

text: 's book The Nature of the Universe, he had the idea that Longman's design resembled a

text: spiral galaxy

text: . He returned to the idea many years later and published a first version of his "galaxy" in November 2004. His design seeks to express the link between the utterly minute world of atoms and the vastness of the stars, in the interior of which the elements were forged, as Hoyle was the first to demonstrate in detail.

text: The brightest elliptical galaxies often have low-density cores that are not well described by Sérsic's law.  The "core-Sérsic" family of models was introduced by A. Graham et al. and Trujillo et al.  and further developed by B. Terzić and A. Graham in 2005 to describe such galaxies.  Core-Sérsic models have an additional set of parameters that describe the core radius and core density.

text: The Spiderweb Galaxy (PGC 2826829, MRC 1138-262) is an irregular galaxy with a redshift of 2.156, which is 10.6 billion light years away. It has been recently imaged by the Hubble Space Telescope. It is formed from dozens of smaller galaxies that were seen in the process of merging through mutual gravitational attraction.

text: The Spiderweb Galaxy (PGC 2826829, MRC 1138-262) is an

text: irregular galaxy

text: with a

text: redshift

text: of 2.156, which is 10.6 billion

text: light year

text: s away. It has been recently imaged by the

text: Hubble Space Telescope

text: . It is formed from dozens of smaller galaxies that were seen in the process of merging through mutual gravitational attraction.

text: Several bright galaxies are found in Ursa Major, including the pair Messier 81 (one of the brightest galaxies in the sky) and Messier 82 above the bear's head, and Pinwheel Galaxy (M101), a spiral northeast of η Ursae Majoris. The spiral galaxies Messier 108 and Messier 109 are also found in this constellation. The bright planetary nebula Owl Nebula (M97) can be found along the bottom of the bowl of the Big Dipper.

text: Several bright

text: galaxies

text: are found in Ursa Major, including the pair

text: Messier 81

text: (one of the brightest galaxies in the sky) and

text: Messier 82

text: above the bear's head, and

text: Pinwheel Galaxy

text: (M101), a spiral northeast of

text: η Ursae Majoris

text: . The

text: spiral galaxies

text: Messier 108

text: and

text: Messier 109

text: are also found in this constellation. The bright

text: planetary nebula

text: Owl Nebula

text: (M97) can be found along the bottom of the bowl of the Big Dipper.

text: -- modelling of star clusters, galaxies, dark matter halos  and galaxy clusters;—constructing anisotropic galaxy models for studies of dynamical instabilities.

text: -- modelling of

text: star cluster

text: s,

text: galaxies

text: dark matter halo

text: s  and

text: galaxy cluster

text: s;—constructing anisotropic galaxy models for studies of dynamical

text: instabilities

text: DDO 70 (also known as Sextans B, PGC 28913 or UGC 5373) is an irregular galaxy which is in the constellation of Sextans. It is located 4.44 million light years away from Earth.

text: DDO 70

text: (also known as

text: Sextans

text: B,

text: PGC

text: 28913 or

text: UGC

text: 5373) is an

text: irregular galaxy

text: which is in the

text: constellation

text: of

text: Sextans

text: . It is located 4.44 million

text: light years

text: away from

text: Earth

text: Most prior models of dark matter assumed it is composed of weakly interacting massive particles (also referred to as "WIMPs") that clump together through gravitational attraction only because the other forces between particles are too weak to affect their motion.  The SIDM picture proposes that the other forces are strong enough for the particles to scatter off one another in regions where they would otherwise pile up (forming what cosmologists call a "cusp") in the center of galaxies.  Also, the scattering would reduce the mass of dwarf galaxies in orbit around larger galaxies because the dark matter particles surrounding the larger galaxy would scatter and, thereby, strip off the dark matter surrounding the dwarf galaxy.  This idea is particularly interesting because there is astronomical evidence suggesting that galaxy cores are not cuspy, and the most massive galaxies predicted by simulations based on WIMPs are not observed.  If the SIDM picture is correct, searches for WIMP dark matter will find nothing, and different approaches will be needed to determine the identity of dark matter.

text: Most prior models of dark matter assumed it is composed of

text: weakly interacting massive particles

text: (also referred to as "WIMPs") that clump together through gravitational attraction only because the other forces between particles are too weak to affect their motion.  The

text: SIDM

text: picture proposes that the other forces are strong enough for the particles to scatter off one another in regions where they would otherwise pile up (forming what cosmologists call a "cusp") in the center of galaxies.  Also, the scattering would reduce the mass of dwarf galaxies in orbit around larger galaxies because the dark matter particles surrounding the larger galaxy would scatter and, thereby, strip off the dark matter surrounding the dwarf galaxy.  This idea is particularly interesting because there is astronomical evidence suggesting that galaxy cores are not cuspy, and the most massive galaxies predicted by simulations based on WIMPs are not observed.  If the SIDM picture is correct, searches for WIMP dark matter will find nothing, and different approaches will be needed to determine the identity of dark matter.

text: The 1966 four-door sedan version of the Galaxie was also produced in Brazil under the names Galaxie, Galaxie 500, LTD and Landau from 1967 to 1983.

text: The 1966 four-door sedan version of the Galaxie was also produced in

text: Brazil

text: under the names Galaxie, Galaxie 500, LTD and

text: Landau

text: from 1967 to 1983.

text: NGC 604 is an H II region inside the Triangulum Galaxy. It was discovered by William Herschel on September 11, 1784. It is one of the largest H II regions in the Local Group of galaxies; at the galaxy's estimated distance of 2.7 million light-years its longest diameter is roughly 1500 light years (460 parsecs), over 40 times the size of the visible portion of the Orion Nebula. It is over 6300 times more luminous than the Orion Nebula, and if it were at the same distance it would outshine Venus. Its gas is ionized by a cluster of massive stars at its center. with 200 stars of spectral type O and WR, a mass of 10 solar masses, and an age of 3.5 million years; however, unlike the Large Magellanic Cloud's Tarantula Nebula central cluster (R136), NGC 604's one is much less compact and more similar to a large stellar association, being considered the prototypical example of a Scaled OB Association (SOBA)

text: NGC 604 is an

text: H II region

text: inside the

text: Triangulum Galaxy

text: . It was discovered by

text: William Herschel

text: on September 11, 1784. It is one of the largest H II regions in the

text: Local Group

text: of galaxies; at the galaxy's estimated distance of 2.7 million

text: light-year

text: s its longest diameter is roughly 1500 light years (460

text: parsec

text: s), over 40 times the size of the visible portion of the

text: Orion Nebula

text: . It is over 6300 times more

text: luminous

text: than the Orion Nebula, and if it were at the same distance it would outshine

text: Venus

text: . Its gas is

text: ionized

text: by a cluster of massive

text: star

text: s at its center. with 200 stars of spectral type

text: O

text: and

text: WR

text: , a mass of 10

text: solar mass

text: es, and an age of 3.5 million years; however, unlike the

text: Large Magellanic Cloud

text: 's

text: Tarantula Nebula

text: central cluster (

text: ), NGC 604's one is much less compact and more similar to a large

text: stellar association

text: , being considered the prototypical example of a Scaled OB Association (SOBA)

text: The Milky Way is the second-largest galaxy in the Local Group, with its stellar disk approximately  in diameter, and, on average, approximately  thick. As a guide to the relative physical scale of the Milky Way, if the Solar System out to Neptune were the size of a US quarter (), the Milky Way would be approximately the size of the continental United States. A ring-like filament of stars wrapping around the Milky Way may actually belong to the Milky Way itself, rippling above and below the relatively flat galactic plane. If so, that would mean a diameter of .

text: The Milky Way is the second-largest galaxy in the

text: Local Group

text: , with its stellar disk approximately  in diameter, and, on average, approximately  thick. As a guide to the relative physical scale of the Milky Way, if the Solar System out to

text: Neptune

text: were the size of a US quarter (), the Milky Way would be approximately the size of the continental United States. A ring-like filament of stars wrapping around the Milky Way may actually belong to the Milky Way itself, rippling above and below the relatively flat galactic plane. If so, that would mean a diameter of .

text: The thin disk is a structural component of certain galaxies. The Milky Way's thin disk is thought to extend up to  in the vertical axis and contributes about 85% of the stars in the Galactic plane. It can be set apart from the thick disc of a galaxy since the latter is composed of older population stars created at an earlier stage of the galaxy formation. Stars in the thin disk, on the other hand, are created as a result of gas accretion at the end stage of a galaxy formation.

text: The thin disk is a structural component of certain

text: galaxies

text: . The

text: Milky Way

text: 's thin disk is thought to extend up to  in the vertical axis and contributes about 85% of the stars in the Galactic plane. It can be set apart from the

text: thick disc

text: of a galaxy since the latter is composed of older population stars created at an earlier stage of the galaxy formation. Stars in the thin disk, on the other hand, are created as a result of gas accretion at the end stage of a galaxy formation.

text: This motion can cause confusion when looking at a solar or galactic spectrum, because the expected redshift based on the simple Hubble law will be obscured by the peculiar motion.  For example, the shape and size of the Virgo Cluster has been a matter of great scientific scrutiny due to the very large peculiar velocities of the galaxies in the cluster.

text: This motion can cause confusion when looking at a solar or galactic spectrum, because the expected redshift based on the simple Hubble law will be obscured by the peculiar motion.  For example, the shape and size of the

text: Virgo Cluster

text: has been a matter of great scientific scrutiny due to the very large peculiar velocities of the galaxies in the cluster.

text: Many characteristics of a galaxy are correlated. For example, as one would expect, a galaxy with a higher luminosity has a larger effective radius. The usefulness of these correlations is when a characteristic that can be determined without prior knowledge of the galaxy's distance (such as central velocity dispersion - the Doppler width of spectral lines in the central parts of the galaxy) can be correlated with a property, such as luminosity, that can be determined only for galaxies of a known distance. With this correlation, one can determine the distance to galaxies, a difficult task in astronomy.

text: Many characteristics of a galaxy are correlated. For example, as one would expect, a galaxy with a higher

text: luminosity

text: has a larger effective radius. The usefulness of these correlations is when a characteristic that can be determined without prior knowledge of the galaxy's distance (such as central velocity dispersion - the Doppler width of spectral lines in the central parts of the galaxy) can be correlated with a property, such as luminosity, that can be determined only for galaxies of a known distance. With this correlation, one can determine the distance to galaxies, a difficult task in astronomy.

text: An ultra diffuse galaxy (UDG) is an extremely-low-density galaxy. Such a galaxy may have the same size as the Milky Way but a visible star count of only 1%. Their lack of luminosity is due to the lack of star-forming gas in the galaxy. This results in old stellar populations.

text: An ultra diffuse galaxy (UDG) is an extremely-low-density

text: galaxy

text: . Such a galaxy may have the same size as the

text: Milky Way

text: but a visible star count of only 1%. Their lack of luminosity is due to the lack of star-forming gas in the galaxy. This results in old stellar populations.

text: The NGC 4038 Group is a group of galaxies across Corvus and Crater. The group may contain between 13 and 27 galaxies. The best-known member is the Antennae peculiar galaxy, located 0.25 north of 31 Crateris.  It consists of two interacting galaxies—NGC 4038 and 4039—that appear to have a heart shape as seen from Earth. The name originates from the huge tidal tails that come off the ends of the two galaxies, formed because of the spiral galaxies' original rotation. Both original galaxies were spiral galaxies and are now experiencing extensive star formation due to the interaction of gas clouds. The galaxies are 45 million light-years from Earth and each has multiple ultraluminous X-ray sources, the source of which is unknown. Astronomers theorize that they may be a rare type of x-ray emitting binary stars or intermediate-mass black holes. The Antennae galaxies appear in a telescope at the 10th magnitude. SN 2004gt was a type Ic supernova that erupted on December 12, 2004. The progenitor was not identified from older images of the galaxy, and is either a type WC Wolf-Rayet star with a mass over 40 times that of the Sun, or a star 20 to 40 times as massive as the Sun in a binary star system. SN 2007sr was a Type Ia supernova event that peaked in brightness on  December 14, 2007. The galaxy has been identified as a good place to take detailed images in case of further supernovae.

text: The

text: NGC 4038 Group

text: is a

text: group of galaxies

text: across Corvus and Crater. The group may contain between 13 and 27 galaxies. The best-known member is the

text: Antennae

text: peculiar galaxy

text: , located 0.25 north of 31 Crateris.  It consists of two

text: interacting

text: galaxies—NGC 4038 and 4039—that appear to have a heart shape as seen from Earth. The name originates from the huge tidal tails that come off the ends of the two galaxies, formed because of the spiral galaxies' original rotation. Both original galaxies were

text: spiral galaxies

text: and are now experiencing extensive

text: star formation

text: due to the interaction of gas clouds. The galaxies are 45 million light-years from Earth and each has multiple

text: ultraluminous X-ray source

text: s, the source of which is unknown. Astronomers theorize that they may be a rare type of x-ray emitting

text: binary star

text: s or

text: intermediate-mass black hole

text: s. The Antennae galaxies appear in a telescope at the 10th magnitude.

text: SN 2004gt

text: was a

text: type Ic supernova

text: that erupted on December 12, 2004. The progenitor was not identified from older images of the galaxy, and is either a type WC

text: Wolf-Rayet star

text: with a mass over 40 times that of

text: the Sun

text: , or a star 20 to 40 times as massive as the Sun in a

text: binary star

text: system.

text: SN 2007sr

text: was a

text: Type Ia supernova

text: event that peaked in brightness on  December 14, 2007. The galaxy has been identified as a good place to take detailed images in case of further supernovae.

text: The 1960 Ford looked all-new with twin headlights riding in a scalloped-square front clip.  The Fairlane was now the base model in the full-sized lineup, along with the Fairlane 500, Galaxie and range-topping Starliner. The Station Wagon Series continued with Ranch Wagon, Country Sedan and Country Squire models. The elegant Starliner 2-door hardtop was Ford's choice for NASCAR racing.  The 1960 fullsize Fords abandoned the ostentatious ornamentation of the 1950s for a futuristic, sleek look.  Round taillights were replaced by half-moon shaped taillights for 1960 only.  There were tailfins still, but smaller ones – the focus of Ford's stylists abandoning, as did the rest of the industry, the aviation influences of the previous decade and instead capturing the new obsession – the Space Race.  The Galaxie name was particularly appealing to this trend, it seems. Windshield wipers were extended to cover more of the windshield. Ford also introduced the center rear fuel door lid.

text: The 1960 Ford looked all-new with twin headlights riding in a scalloped-square front clip.  The Fairlane was now the base model in the full-sized lineup, along with the Fairlane 500, Galaxie and range-topping Starliner. The Station Wagon Series continued with Ranch Wagon, Country Sedan and Country Squire models. The elegant Starliner 2-door

text: hardtop

text: was Ford's choice for

text: NASCAR

text: racing.  The 1960 fullsize Fords abandoned the ostentatious ornamentation of the 1950s for a futuristic, sleek look.  Round taillights were replaced by half-moon shaped taillights for 1960 only.  There were tailfins still, but smaller ones – the focus of Ford's stylists abandoning, as did the rest of the industry, the aviation influences of the previous decade and instead capturing the new obsession – the

text: Space Race

text: .  The Galaxie name was particularly appealing to this trend, it seems. Windshield wipers were extended to cover more of the windshield. Ford also introduced the center rear fuel door lid.

text: A lenticular galaxy is a type of galaxy intermediate between an elliptical and a spiral galaxy in galaxy morphological classification schemes. Lenticular galaxies are disc galaxies (like spiral galaxies) that have used up or lost most of their interstellar matter and therefore have very little ongoing star formation. They may, however, retain significant dust in their disks. As a result, they consist mainly of aging stars (like elliptical galaxies). Because of their ill-defined spiral arms, if they are inclined face-on it is often difficult to distinguish between them and elliptical galaxies. Despite the morphological differences, lenticular and elliptical galaxies share common properties like spectral features and scaling relations. Both can be considered early-type galaxies that are passively evolving, at least in the local part of the Universe.

text: A lenticular galaxy is a type of

text: galaxy

text: intermediate between an

text: elliptical

text: and a

text: spiral galaxy

text: in

text: galaxy morphological classification

text: schemes. Lenticular galaxies are

text: disc galaxies

text: (like spiral galaxies) that have used up or lost most of their

text: interstellar matter

text: and therefore have very little ongoing

text: star formation

text: . They may, however, retain significant dust in their disks. As a result, they consist mainly of aging stars (like elliptical galaxies). Because of their ill-defined

text: spiral arm

text: s, if they are inclined face-on it is often difficult to distinguish between them and elliptical galaxies. Despite the morphological differences, lenticular and elliptical galaxies share common properties like spectral features and scaling relations. Both can be considered early-type galaxies that are passively evolving, at least in the local part of the Universe.

text: Size: For a body of fissile material in any given shape, increasing the size of the body increases the average distance that neutrons must travel before they can reach the surface and escape. Hence, increasing the size of the body increases the likelihood of fission and decreases the likelihood of leakage. Hence, for any given shape (and reflection conditions - see below) there will be a size that gives an exact balance between the rate of neutron production and the combined rate of absorption and leakage. This is the critical size.

text: Zwicky also notes, in the same paper, that according to a tired light model a distance-redshift relationship would necessarily be present in the light from sources within our own galaxy (even if the redshift would be so small that it would be hard to measure), that do not appear under a recessional-velocity based theory. He writes, referring to sources of light within our galaxy: "It is especially desirable to determine the redshift independent of the proper velocities of the objects observed". Subsequent to this, astronomers have patiently mapped out the three-dimensional velocity-position phase space for the galaxy and found the redshifts and blueshifts of galactic objects to accord well with the statistical distribution of a spiral galaxy, eliminating the intrinsic redshift component as an effect.

text: Zwicky also notes, in the same paper, that according to a tired light model a distance-redshift relationship would necessarily be present in the light from sources within our own galaxy (even if the redshift would be so small that it would be hard to measure), that do not appear under a recessional-velocity based theory. He writes, referring to sources of light within our galaxy: "It is especially desirable to determine the redshift independent of the proper velocities of the objects observed". Subsequent to this, astronomers have patiently mapped out the three-dimensional velocity-position

text: phase space

text: for the galaxy and found the redshifts and blueshifts of galactic objects to accord well with the statistical distribution of a spiral galaxy, eliminating the

entity_section: Redshift periodicity and intrinsic redshifts

text: intrinsic redshift

text: component as an effect.

text: Dwarf elliptical galaxies, or dEs, are elliptical galaxies that are much smaller than others. They are classified as dE, and are quite common in galaxy groups and clusters, and are usually companions to other galaxies.

text: Dwarf elliptical galaxies, or dEs, are

text: elliptical galaxies

text: that are much smaller than others. They are classified as dE, and are quite common in galaxy groups and clusters, and are usually companions to other galaxies.

text: The Sombrero Galaxy is an unbarred spiral galaxy.

text: The

text: Sombrero Galaxy

text: is an unbarred spiral galaxy.

text: Finally the tidal radius, or Hill sphere, is the distance from the center of the globular cluster at which the external gravitation of the galaxy has more influence over the stars in the cluster than does the cluster itself. This is the distance at which the individual stars belonging to a cluster can be separated away by the galaxy. The tidal radius of M3 is about 40 arc minutes, or about 113 pc at the distance of 10.4 kpc.

text: Finally the tidal radius, or

text: Hill sphere

text: , is the distance from the center of the globular cluster at which the external gravitation of the galaxy has more influence over the stars in the cluster than does the cluster itself. This is the distance at which the individual stars belonging to a cluster can be separated away by the galaxy. The tidal radius of M3 is about 40 arc minutes, or about 113 pc at the distance of 10.4 kpc.

text: In 1997, the Hubble telescope discovered a large number of intergalactic stars in the Virgo cluster of galaxies. Later in the 1990s scientists discovered another group of intergalactic stars in the Fornax cluster of galaxies.

text: In 1997, the

text: Hubble telescope

text: discovered a large number of intergalactic stars in the Virgo cluster of galaxies. Later in the 1990s scientists discovered another group of intergalactic stars in the

text: Fornax cluster

text: of galaxies.

text: Ford built 200 lightweight Ford Galaxies for drag racing in 1963. All non-essential equipment was omitted. Modifications included fiberglass panels, aluminum bumpers, traction bars, and a competition-specification  engine factory rated at a conservative . This full-size car could run the quarter mile in a little over 12 seconds. Also built in 1963 were 5,000 road-legal versions that could be used as every day drivers (Ford claimed 0-60 in less than 6 seconds for the similarly powered 1966 Galaxie 500XL 427).

text: Ford built 200 lightweight Ford Galaxies for drag racing in 1963. All non-essential equipment was omitted. Modifications included fiberglass panels, aluminum bumpers, traction bars, and a competition-specification  engine factory rated at a conservative . This

text: full-size

text: car could run the quarter mile in a little over 12 seconds. Also built in 1963 were 5,000 road-legal versions that could be used as every day drivers (Ford claimed 0-60 in less than 6 seconds for the similarly powered 1966 Galaxie 500XL 427).

text: Stars and interstellar gas are bound by gravity to form galaxies, and groups of galaxies can be bound by gravity in galaxy clusters. With the exception of stars in the Milky Way and the galaxies in the Local Group, almost all galaxies are moving away from us due to the expansion of the universe.

text: Stars and interstellar gas are bound by gravity to form galaxies, and groups of galaxies can be bound by gravity in

text: galaxy clusters

text: . With the exception of stars in the

text: Milky Way

text: and the galaxies in the

text: Local Group

text: , almost all galaxies are moving away from us due to the

text: expansion of the universe

text: Even though its mass is slightly larger than that of the Milky Way, the spiral will inevitably lose all its gas and dust as well as its chance of generating new stars later, and become a gas-poor galaxy with an old population of red stars. The finding sheds light on the process by which gas-rich galaxies might evolve into gas-poor galaxies over billions of years. The new observations also reveal one mechanism for forming of “homeless” stars seen scattered throughout galaxy clusters.

text: A satellite galaxy is a galaxy that orbits a larger galaxy due to gravitational attraction. Although a galaxy is made of a large number of objects (such as stars, planets, and nebulae) that are not connected to each other, it has a center of mass, which represents a weighted average (by mass) of the positions of each component object.  This is similar to how an everyday object has a center of mass which is the weighted average of the positions of all its component atoms. Even within a satellite galaxy, the stars in turn orbit the galactic center.

text: A satellite galaxy is a galaxy that

text: orbit

text: s a larger galaxy due to

text: gravitational attraction

text: . Although a

text: galaxy

text: is made of a large number of objects (such as

text: star

text: s,

text: planet

text: s, and

text: nebula

text: e) that are not connected to each other, it has a

text: center of mass

text: , which represents a weighted average (by mass) of the positions of each component object.  This is similar to how an everyday object has a center of mass which is the weighted average of the positions of all its component

text: atom

text: s. Even within a satellite galaxy, the stars in turn orbit the galactic center.

text: A common misconception is that kits were used for children. In fact, they were made for adults—their small size is so that they could be used in situations where a full-sized violin was too large to carry, or too expensive to own.  The "pocket fiddle" or "pochette" should not be confused with a saddle fiddle, the latter being a proper fiddle or violin with a nearly full-sized finger board, and a violin body that is the same shape as a full-sized version.

text: From 1959 to 1964, the Fairlane was a locally assembled version of the American Ford Fairlane which had taken its name from Henry Ford's estate, Fair Lane, near Dearborn, Michigan. This was Ford Australia's top-of-the-range model until replaced by an Australian-assembled version of the full-size American Ford Galaxie. In 1967, Ford Australia reintroduced the Fairlane, this time as an Australian-developed, luxury, long-wheelbase version of its mainstream Falcon, positioned between the Falcon and the Galaxie. The locally assembled Galaxie evolved into the LTD which was itself replaced in 1973 by an Australian-developed, Fairlane-based model, also known as the Ford LTD. In North America, unlike its designation in Australia, it was not considered a luxury vehicle. In Australia, "LTD" originally stood for "Lincoln Type Design", although Ford Australia later promoted a connection with the meaning "Limited".

text: From 1959 to 1964, the Fairlane was a locally assembled version of the American

text: Ford Fairlane

text: which had taken its name from

text: Henry Ford

text: 's estate,

text: Fair Lane

text: , near

text: Dearborn, Michigan

text: . This was Ford Australia's top-of-the-range model until replaced by an Australian-assembled version of the full-size American

text: Ford Galaxie

text: . In 1967, Ford Australia reintroduced the Fairlane, this time as an Australian-developed, luxury, long-wheelbase version of its mainstream

text: Falcon

text: , positioned between the Falcon and the Galaxie. The locally assembled Galaxie evolved into the

text: LTD

text: which was itself replaced in 1973 by an Australian-developed, Fairlane-based model, also known as the Ford LTD. In North America, unlike its designation in Australia, it was not considered a luxury vehicle. In Australia, "LTD" originally stood for "Lincoln Type Design", although Ford Australia later promoted a connection with the meaning "Limited".

text: H II regions are found only in spiral galaxies like the Milky Way and irregular galaxies. They are not seen in elliptical galaxies. In irregular galaxies, they may be dispersed throughout the galaxy, but in spirals they are most abundant within the spiral arms. A large spiral galaxy may contain thousands of H II regions.

text: H II regions are found only in

text: spiral galaxies

text: like the Milky Way and

text: irregular galaxies

text: . They are not seen in

text: elliptical galaxies

text: . In irregular galaxies, they may be dispersed throughout the galaxy, but in spirals they are most abundant within the spiral arms. A large spiral galaxy may contain thousands of H II regions.

text: In the updated Hubble sequence galaxy morphological classification scheme by the French astronomer Gérard de Vaucouleurs in 1959, NGC 4889 is classified as an E4 type galaxy, which means it has a flat distribution of stars within its width. It is also classified as a cD galaxy, a giant type of D galaxy, a classification devised by the American astronomer William Wilson Morgan in 1958 for galaxies with an elliptical-shaped nucleus surrounded by an immense, diffuse, dustless, extended halo.

text: In the updated

text: Hubble sequence

text: galaxy morphological classification

text: scheme by the French astronomer

text: Gérard de Vaucouleurs

text: in 1959, NGC 4889 is classified as an E4 type galaxy, which means it has a flat distribution of stars within its width. It is also classified as a cD galaxy, a giant type of D galaxy, a classification devised by the

text: American

text: astronomer

text: William Wilson Morgan

text: in 1958 for galaxies with an elliptical-shaped nucleus surrounded by an immense, diffuse, dustless, extended halo.

text: The reason H II regions rarely appear in elliptical galaxies is that ellipticals are believed to form through galaxy mergers. In galaxy clusters, such mergers are frequent. When galaxies collide, individual stars almost never collide, but the GMCs and H II regions in the colliding galaxies are severely agitated. Under these conditions, enormous bursts of star formation are triggered, so rapid that most of the gas is converted into stars rather than the normal rate of 10% or less.

text: The reason H II regions rarely appear in elliptical galaxies is that ellipticals are believed to form through galaxy mergers. In

text: galaxy cluster

text: s, such mergers are frequent. When galaxies collide, individual stars almost never collide, but the GMCs and H II regions in the colliding galaxies are severely agitated. Under these conditions, enormous bursts of star formation are triggered, so rapid that most of the gas is converted into stars rather than the normal rate of 10% or less.

text: The final images were released at a meeting of the American Astronomical Society in January 1996, and revealed a plethora of distant, faint galaxies. About 3,000 distinct galaxies could be identified in the images, with both irregular and spiral galaxies clearly visible, although some galaxies in the field are only a few pixels across. In all, the HDF is thought to contain fewer than twenty galactic foreground stars; by far the majority of objects in the field are distant galaxies.

text: The final images were released at a meeting of the

text: American Astronomical Society

text: in January 1996, and revealed a plethora of distant, faint galaxies. About 3,000 distinct galaxies could be identified in the images, with both

text: irregular

text: and

text: spiral galaxies

text: clearly visible, although some galaxies in the field are only a few pixels across. In all, the HDF is thought to contain fewer than twenty galactic foreground stars; by far the majority of objects in the field are distant galaxies.

text: Although it appears that globular clusters contain some of the first stars to be produced in the galaxy, their origins and their role in galactic evolution are still unclear. It does appear clear that globular clusters are significantly different from dwarf elliptical galaxies and were formed as part of the star formation of the parent galaxy rather than as a separate galaxy.

text: Although it appears that globular clusters contain some of the first stars to be produced in the galaxy, their

text: origins

text: and their role in galactic evolution are still unclear. It does appear clear that globular clusters are significantly different from

text: dwarf elliptical galaxies

text: and were formed as part of the star formation of the parent galaxy rather than as a separate galaxy.

text: Examples of irregular galaxies: M82, NGC 1427A, Large Magellanic Cloud, Small Magellanic Cloud.

text: Examples of irregular galaxies:

text: NGC 1427A

text: Large Magellanic Cloud

text: Small Magellanic Cloud

text: Other notable spiral galaxies in Canes Venatici are the Sunflower Galaxy (M63, NGC 5055), M94 (NGC 4736), and M106 (NGC 4258). M63, the Sunflower Galaxy, was named for its appearance in large amateur telescopes. It is a spiral galaxy with an integrated magnitude of 9.0. M94 is a small face-on spiral galaxy with an approximate magnitude of 8.0, about 15 million light-years from Earth. NGC 4631 is a barred spiral galaxy, which is one of the largest and brightest edge-on galaxies in the sky.

text: Other notable spiral galaxies in Canes Venatici are the

text: Sunflower Galaxy

text: (M63, NGC 5055),

text: (NGC 4736), and

text: (NGC 4258). M63, the Sunflower Galaxy, was named for its appearance in large amateur telescopes. It is a spiral galaxy with an integrated magnitude of 9.0. M94 is a small face-on spiral galaxy with an approximate magnitude of 8.0, about 15 million light-years from Earth.

text: NGC 4631

text: is a barred spiral galaxy, which is one of the largest and brightest edge-on galaxies in the sky.

text: The result of N-body simulations suggests that the universe is composed largely of voids, whose densities might be as low as one tenth the cosmological mean. The matter condenses in large filaments and haloes which have an intricate web-like structure. These form galaxy groups, clusters and superclusters. While the simulations appear to agree broadly with observations, their interpretation is complicated by the understanding of how dense accumulations of dark matter spur galaxy formation. In particular, many more small haloes form than we see in astronomical observations as dwarf galaxies and globular clusters. This is known as the galaxy bias problem, and a variety of explanations have been proposed. Most account for it as an effect in the complicated physics of galaxy formation, but some have suggested that it is a problem with our model of dark matter and that some effect, such as warm dark matter, prevents the formation of the smallest haloes.

text: The result of N-body simulations suggests that the universe is composed largely of

text: void

text: s, whose densities might be as low as one tenth the cosmological mean. The matter condenses in large

text: filament

text: s and

text: halo

text: es which have an intricate web-like structure. These form

text: galaxy

text: groups, clusters

text: and

text: supercluster

text: s. While the simulations appear to agree broadly with observations, their interpretation is complicated by the understanding of how dense accumulations of dark matter spur galaxy formation. In particular, many more small haloes form than we see in astronomical observations as

text: dwarf galaxies

text: and

text: globular cluster

text: s. This is known as the

text: galaxy bias

text: problem, and a variety of explanations have been proposed. Most account for it as an effect in the complicated physics of galaxy formation, but some have suggested that it is a problem with our model of

text: dark matter

text: and that some effect, such as

text: warm dark matter

text: , prevents the formation of the smallest haloes.

text: The Milky Way galaxy falls within the Local Group, which is a poor and irregular cluster of galaxies. Poor clusters may contain only a few dozen galaxies, as compared to rich clusters with hundreds or even thousands. The Local Group is near the Local Supercluster (also known as the Virgo Supercluster), which has a diameter of 100 million light-years. The Local Supercluster contains a total of about 10 times the mass of the Sun.

text: The Milky Way galaxy falls within the Local Group, which is a poor and irregular cluster of galaxies. Poor clusters may contain only a few dozen galaxies, as compared to rich clusters with hundreds or even thousands. The Local Group is near the Local Supercluster (also known as the

text: Virgo Supercluster

text: ), which has a diameter of 100 million light-years. The Local Supercluster contains a total of about 10 times the mass of the Sun.

text: Examples of elliptical galaxies: M49, M59, M60, M87, NGC 4125.

text: Examples of elliptical galaxies:

text: NGC 4125

text: A low-mass X-ray binary (LMXB) is a binary star system where one of the components is either a black hole or neutron star.  The other component, a donor, usually fills its Roche lobe and therefore transfers mass to the compact star.  The donor is less massive than the compact object, and can be on the main sequence, a degenerate dwarf (white dwarf), or an evolved star (red giant).  Approximately two hundred LMXBs have been detected in the Milky Way, and of these, thirteen LMXBs have been discovered in globular clusters.  The Chandra X-ray Observatory has revealed LMXBs in many distant galaxies.

text: A low-mass X-ray binary (LMXB) is a

text: binary star

text: system where one of the components is either a

text: black hole

text: or

text: neutron star

text: .  The other component, a donor, usually fills its

text: Roche lobe

text: and therefore transfers mass to the compact star.  The donor is less massive than the compact object, and can be on the

text: main sequence

text: , a degenerate dwarf (

text: white dwarf

text: ), or an evolved star (

text: red giant

text: ).  Approximately two hundred LMXBs have been detected in the

text: Milky Way

text: , and of these, thirteen LMXBs have been discovered in

text: globular cluster

text: s.  The

text: Chandra X-ray Observatory

text: has revealed LMXBs in many distant galaxies.

text: The rate of star formation in the Milky Way is much higher, with Andromeda Galaxy producing only about one solar mass per year compared to 3–5 solar masses for the Milky Way. The rate of supernovae in the Milky Way is also double that of Andromeda Galaxy. This suggests that the latter once experienced a great star formation phase, but is now in a relative state of quiescence, whereas the Milky Way is experiencing more active star formation. Should this continue, the luminosity in the Milky Way may eventually overtake that of Andromeda Galaxy.

text: The rate of star formation in the Milky Way is much higher, with Andromeda Galaxy producing only about one solar mass per year compared to 3–5 solar masses for the Milky Way. The rate of

text: supernova

text: e in the Milky Way is also double that of Andromeda Galaxy. This suggests that the latter once experienced a great star formation phase, but is now in a relative state of quiescence, whereas the Milky Way is experiencing more active star formation. Should this continue, the luminosity in the Milky Way may eventually overtake that of Andromeda Galaxy.

text: Our own galaxy, the Milky Way, is a large disk-shaped barred-spiral galaxy about 30 kiloparsecs in diameter and a kiloparsec thick. It contains about two hundred billion (2×10) stars and has a total mass of about six hundred billion (6×10) times the mass of the Sun.

text: Our own galaxy, the

text: Milky Way

text: , is a large disk-shaped barred-spiral galaxy about 30 kiloparsecs in diameter and a kiloparsec thick. It contains about two hundred billion (2×10) stars and has a total mass of about six hundred billion (6×10) times the mass of the Sun.

text: Notable galaxy clusters in the relatively nearby Universe include the Virgo Cluster, Fornax Cluster, Hercules Cluster, and the Coma Cluster. A very large aggregation of galaxies known as the Great Attractor, dominated by the Norma Cluster, is massive enough to affect the local expansion of the Universe. Notable galaxy clusters in the distant, high-redshift Universe include SPT-CL J0546-5345 and SPT-CL J2106-5844, the most massive galaxy clusters found in the early Universe. In the last few decades, they are also found to be relevant sites of particle acceleration, a feature that has been discovered by observing non-thermal diffuse radio emissions, such as radio halos and radio relics. Using the Chandra X-ray Observatory, structures such as cold fronts and shock waves have also been found in many galaxy clusters.

text: Notable galaxy clusters in the relatively nearby Universe include the

text: Virgo Cluster

text: Fornax Cluster

text: Hercules Cluster

text: , and the

text: Coma Cluster

text: . A very large aggregation of galaxies known as the

text: Great Attractor

text: , dominated by the

text: Norma Cluster

text: , is massive enough to affect the

text: local expansion of the Universe

text: . Notable galaxy clusters in the distant, high-redshift Universe include

text: SPT-CL J0546-5345

text: and

text: SPT-CL J2106-5844

text: , the most massive galaxy clusters found in the early Universe. In the last few decades, they are also found to be relevant sites of particle acceleration, a feature that has been discovered by observing non-thermal diffuse radio emissions, such as

text: radio halo

text: s and

text: radio relics

text: . Using the

text: Chandra X-ray Observatory

text: , structures such as cold fronts and

text: shock waves

text: have also been found in many galaxy clusters.

text: She also grew to hate Fifth for his actions, seeing him as nothing more than a weakling which also resulted in her becoming a major adversary in the eighth season of the series, threatening the entire Milky Way galaxy and its people.

text: The Large Magellanic Cloud is usually considered an irregular galaxy. However, it shows signs of a bar structure, and is often reclassified as a Magellanic-type dwarf spiral galaxy.

text: The Large Magellanic Cloud is usually considered an

text: irregular galaxy

text: . However, it shows signs of a bar structure, and is often reclassified as a

text: Magellanic-type

text: dwarf spiral galaxy

text: Samsung Galaxy A8 refers to two Samsung Galaxy Android smart phones released in 2015 and 216.

text: Samsung Galaxy A8 refers to two

text: Samsung Galaxy

text: Android

text: smart phones

text: released in 2015 and 216.

text: DDO 69 (also known as Leo A, Leo III, PGC 28868 or UGC 5364) is an irregular galaxy which is located in the constellation of Leo. It is a small satellite galaxy of our galaxy, the Milky Way.

text: DDO 69

text: (also known as

text: Leo

text: A,

text: Leo

text: III,

text: PGC

text: 28868 or

text: UGC

text: 5364) is an

text: irregular galaxy

text: which is located in the

text: constellation

text: of

text: Leo

text: . It is a small

text: satellite galaxy

text: of our

text: galaxy

text: the Milky Way

text: One of the original aims for Galaxy Zoo was to explore which way galaxies rotated. Cosmologist Kate Land stated: "Some people have argued that galaxies are rotating all in agreement with each other, not randomly as we'd expect. We want people to classify the galaxies according to which way they're rotating and I'll be able to go and see if there's anything bizarre going on. If there are any patterns that we're not expecting, it could really turn up some surprises." In Galaxy Zoo 1, volunteers were asked to judge from the SDSS images whether the galaxies were elliptical or spiral and, if spiral, whether they were rotating in a clockwise or anti-clockwise direction. The rotation, also called the Chirality, of galaxies has been examined in several Galaxy Zoo related papers.

text: One of the original aims for Galaxy Zoo was to explore which way galaxies rotated. Cosmologist Kate Land stated: "Some people have argued that galaxies are rotating all in agreement with each other, not randomly as we'd expect. We want people to classify the galaxies according to which way they're rotating and I'll be able to go and see if there's anything bizarre going on. If there are any patterns that we're not expecting, it could really turn up some surprises." In Galaxy Zoo 1, volunteers were asked to judge from the

text: SDSS

text: images whether the galaxies were

text: elliptical

text: or

text: spiral

text: and, if spiral, whether they were rotating in a

text: clockwise

text: or

text: anti-clockwise

text: direction. The rotation, also called the

text: Chirality

text: , of galaxies has been examined in several Galaxy Zoo related papers.

text: The stream covers over 100 square degrees, and possibly as much as 1,000 square degrees (approximately 5% of the hemisphere visible at any one time, or 5,000 times the area of the full moon).  Despite its proximity to the solar system and the solid angle that it consequently covers, the stream contains only a few hundred thousand stars.  The low surface brightness of the galaxy (possibly as low as 32.5 mag/arcmin²) may have militated against its detection in surveys before SDSS.  The number of stars in the stream is not greatly in excess of a star cluster, and it has been described by a member of the team that discovered it as "a rather pathetic galaxy", in comparison to the Milky Way.  Many of the stars have been known for centuries and thought of as normal Milky Way stars, although they have a lower metallicity than normal Population I stars in the Milky Way.

text: The stream covers over 100

text: square degree

text: s, and possibly as much as 1,000 square degrees (approximately 5% of the

text: hemisphere

text: visible at any one time, or 5,000 times the area of the

text: full moon

text: ).  Despite its proximity to the

text: solar system

text: and the

text: solid angle

text: that it consequently covers, the stream contains only a few hundred thousand stars.  The low

text: surface brightness

text: of the galaxy (possibly as low as 32.5

text: mag

entity_section: Symbols.2C abbreviations and subdivisions

text: arcmin

text: ²) may have militated against its detection in surveys before SDSS.  The number of stars in the stream is not greatly in excess of a

text: star cluster

text: , and it has been described by a member of the team that discovered it as "a rather pathetic galaxy", in comparison to the Milky Way.  Many of the stars have been known for centuries and thought of as normal Milky Way stars, although they have a lower

text: metallicity

text: than normal

text: Population I

text: stars in the Milky Way.

text: The typical average equipartition strength for spiral galaxies is about 10 μG (microGauss) or 1 nT (nanoTesla). For comparison, the Earth's magnetic field has an average strength of about 0.3 G (Gauss or 30 μT (microTesla)). Radio-faint galaxies like M 31 and M 33, our Milky Way's neighbors, have weaker fields (about 5 μG), while gas-rich galaxies with high star-formation rates, like M 51, M 83 and NGC 6946, have 15 μG on average. In prominent spiral arms the field strength can be up to 25 μG, in regions where also cold gas and dust are concentrated. The strongest total equipartition fields (50-100 μG) were found in starburst galaxies, for example in M 82 and the Antennae, and in nuclear starburst regions, for example in the centers of NGC 1097 and of other barred galaxies.

text: The typical average

text: equipartition strength

text: for

text: spiral galaxies

text: is about 10 μG (

text: microGauss

text: ) or 1 nT (

text: nanoTesla

text: ). For comparison, the Earth's magnetic field has an average strength of about 0.3 G (Gauss or 30 μT (

text: microTesla)

text: ). Radio-faint galaxies like

text: M 31

text: and

text: M 33

text: , our

text: Milky Way

text: 's neighbors, have weaker fields (about 5 μG), while gas-rich galaxies with high star-formation rates, like M 51, M 83 and NGC 6946, have 15 μG on average. In prominent spiral arms the field strength can be up to 25 μG, in regions where also cold gas and dust are concentrated. The strongest total equipartition fields (50-100 μG) were found in

text: starburst galaxies

text: , for example in M 82 and the

text: Antennae

text: , and in nuclear starburst regions, for example in the centers of NGC 1097 and of other

text: barred galaxies

text: After the timeskip, Makken is married to Leite with three children. Sadly, he is killed in the first deep space battle versus the Anti-Spirals, after sacrificing himself to stop a large Anti-Spiral missile from destroying the Super Galaxy Dai-Gurren.

text: SAm galaxies are a type of unbarred spiral galaxy, while SBm are a type of barred spiral galaxy. SABm are a type of intermediate spiral galaxy.

text: SAm galaxies are a type of

text: unbarred spiral galaxy

text: , while SBm are a type of

text: barred spiral galaxy

text: . SABm are a type of

text: intermediate spiral galaxy

text: These are galaxies that look like a stretched-out S shape (or like the integral sign used in calculus). Some objects, such as IC 167, are simply ordinary spiral galaxies viewed from an unusual angle.  Other objects, such as UGC 10770, are interacting pairs of galaxies with tidal tails that look similar to spiral arms.

text: These are galaxies that look like a stretched-out S shape (or like the integral sign used in

text: calculus

text: ). Some objects, such as

text: IC 167

text: , are simply ordinary spiral galaxies viewed from an unusual angle.  Other objects, such as

text: UGC 10770

text: , are interacting pairs of galaxies with tidal tails that look similar to spiral arms.

text: Pisces Dwarf is an irregular dwarf galaxy that is part of the Local Group.  The galaxy, taking its name from the constellation Pisces where it appears, is suspected of being a satellite galaxy of the Triangulum Galaxy (M33).   It displays a blueshift, as it is approaching the Milky Way at 287 km/s. It may be transition-type galaxy, somewhere between dwarf spheroidal and dwarf irregular. Alternatively, it may be a rare, but statistically acceptable, version of one of the two types.

text: Pisces Dwarf is an

text: irregular

text: dwarf

text: galaxy

text: that is part of the

text: Local Group

text: .  The galaxy, taking its name from the

text: constellation

text: Pisces

text: where it appears, is suspected of being a

text: satellite galaxy

text: of the

text: Triangulum Galaxy

text: (M33).   It displays a

text: blueshift

text: , as it is approaching the

text: Milky Way

text: at 287

text: km/s

text: . It may be transition-type galaxy, somewhere between

text: dwarf spheroidal

text: and

text: dwarf irregular

text: . Alternatively, it may be a rare, but statistically acceptable, version of one of the two types.

text: Messier 90 is a member of the Virgo Cluster, being  one of its largest and brightest spiral galaxies, with an absolute magnitude of around -22 (brighter than the Andromeda Galaxy). The galaxy is located approximately 1°.5 away from the subgroup centered on Messier 87.  As a consequence of the galaxy's interaction with the intracluster medium in the Virgo Cluster, the galaxy has lost much of its interstellar medium.  As a result of this process, which is referred to as ram-pressure stripping, the galaxy's interstellar medium and star formation regions appear severely truncated compared to similar galaxies outside the Virgo Cluster and there are even H II regions outside the galactic plane, as well as long (up to 80 kpcs, 260,000 light-years) tails of ionized gas that has been stripped of M90.

text: Messier 90 is a member of the

text: Virgo Cluster

text: , being  one of its largest and brightest spiral galaxies, with an

text: absolute magnitude

text: of around -22 (brighter than the

text: Andromeda Galaxy

text: ). The galaxy is located approximately 1°.5 away from the subgroup centered on

text: Messier 87

text: .  As a consequence of the galaxy's interaction with the

text: intracluster medium

text: in the Virgo Cluster, the galaxy has lost much of its

text: interstellar medium

text: .  As a result of this process, which is referred to as

text: ram-pressure stripping

text: , the galaxy's interstellar medium and

text: star formation region

text: s appear severely truncated compared to similar galaxies outside the Virgo Cluster and there are even

text: H II region

text: s outside the

text: galactic plane

text: , as well as long (up to 80 k

text: pc

text: s, 260,000 light-years) tails of ionized gas that has been stripped of M90.

text: Passive spiral galaxies (also known as passive spirals) are a type of spiral galaxy located in rich galaxy clusters at high redshifts that present spiral structure, but little or no star formation, in some cases hidden by dust and concentrated within its innermost regions. Often, they seem too to have few or no massive (>20 solar masses) stars.

text: Passive spiral galaxies (also known as passive spirals) are a type of spiral galaxy located in rich galaxy clusters at high

text: redshift

text: s that present spiral structure, but little or no star formation, in some cases hidden by

text: dust

text: and concentrated within its innermost regions. Often, they seem too to have few or no

text: massive

text: solar mass

text: es) stars.

text: Galaxies in this category are almost always clearly interacting sources. The most famous of these objects is the Whirlpool galaxy (M51; Arp 85), which is composed of a spiral galaxy NGC 5194 that is interacting with a smaller elliptical galaxy NGC 5195. The interaction has distorted the shape of both galaxies; the spiral arm pattern has been enhanced in the larger spiral galaxy, and a bridge of stars and gas has formed between the two galaxies. Many of the other galaxies in this category are also connected by bridges.

text: Galaxies in this category are almost always clearly interacting sources. The most famous of these objects is

text: the Whirlpool galaxy (M51; Arp 85)

text: , which is composed of a spiral galaxy

text: NGC 5194

text: that is interacting with a smaller elliptical galaxy

text: NGC 5195

text: . The interaction has distorted the shape of both galaxies; the spiral arm pattern has been enhanced in the larger spiral galaxy, and a bridge of stars and gas has formed between the two galaxies. Many of the other galaxies in this category are also connected by bridges.

text: A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter. The word galaxy is derived from the Greek  (γαλαξίας), literally "milky", a reference to the Milky Way. Galaxies range in size from dwarfs with just a few billion (10) stars to giants with one hundred trillion (10) stars, each orbiting its galaxy's center of mass. Galaxies are categorized according to their visual morphology as elliptical, spiral and irregular. Many galaxies are thought to have black holes at their active centers. The Milky Way's central black hole, known as Sagittarius A*, has a mass four million times greater than the Sun. As of March 2016, GN-z11 is the oldest and most distant observed galaxy with a comoving distance of 32 billion light-years from Earth, and observed as it existed just 400 million years after the Big Bang. Previously, as of July 2015, EGSY8p7 was the most distant known galaxy, estimated to have a light travel distance of 13.2 billion light-years away.

text: A galaxy is a

text: gravitation

text: ally bound system of

text: star

text: s,

text: stellar remnant

text: s,

text: interstellar gas

text: dust

text: , and

text: dark matter

text: . The word galaxy is derived from the

text: Greek

text: (γαλαξίας), literally "milky", a reference to the

text: Milky Way

text: . Galaxies range in size from

text: dwarfs

text: with just a few billion (10) stars to giants with one hundred

text: trillion

text: (10) stars, each orbiting its galaxy's

text: center of mass

text: . Galaxies are categorized according to their visual morphology as

text: elliptical

text: spiral

text: and

text: irregular

text: . Many galaxies are thought to have

text: black hole

text: s at their

text: active centers

text: . The Milky Way's central black hole, known as

text: Sagittarius A*

text: , has a mass four million times greater than the

text: Sun

text: . As of March 2016,

text: is the oldest and most distant observed galaxy with a

text: comoving distance

text: of 32 billion

text: light-years

text: from Earth, and observed as it existed just 400 million years after the Big Bang. Previously, as of July 2015,

text: was the most distant known galaxy, estimated to have a light travel distance of 13.2 billion light-years away.

text: The Butcher–Oemler conclusion generated numerous investigations of the cores of rich clusters at intermediate redshift (0.3 ≤ z ≤ 0.9): Couch and Newell (1984), like Butcher and Oemler, acquired broadband photometry of such environments.  Couch et al. (1983), Ellis et al. (1985), MacLaren, Ellis and Couch (1988), Aragon-Salamanca, Ellis and Sharples (1991) and Aragon-Salamanca et al. (1993) imaged clusters with redshifts between 0.5 ≤ z ≤ 0.9 in both optical and infrared bands.  Spectroscopic observations were conducted by Dressler and Gunn (1982), Lavery and Henry (1985) and Couch and Sharples (1987).  Studies of the morphologies of the galaxies in the cores of these clusters were undertaken using the Hubble Space Telescope by Couch et al. (1994) and Dressler et al. (1994).  The outcome of these investigations is that the Butcher–Oemler effect is widespread in rich clusters at z > 0.2 and is due to vigorous episodes of star formation in a subset of the cluster members.

text: The Butcher–Oemler conclusion generated numerous investigations of the cores of rich clusters at intermediate redshift (0.3 ≤ z ≤ 0.9):

text: Couch

text: and Newell (1984), like Butcher and Oemler, acquired broadband photometry of such environments.  Couch et al. (1983), Ellis et al. (1985), MacLaren,

text: Ellis

text: and Couch (1988), Aragon-Salamanca, Ellis and Sharples (1991) and Aragon-Salamanca et al. (1993) imaged clusters with redshifts between 0.5 ≤ z ≤ 0.9 in both

text: optical

text: and

text: infrared

text: bands.

text: Spectroscopic

text: observations were conducted by Dressler and

text: Gunn

text: (1982), Lavery and Henry (1985) and Couch and Sharples (1987).  Studies of the

text: morphologies

text: of the galaxies in the cores of these clusters were undertaken using the

text: Hubble Space Telescope

text: by Couch et al. (1994) and Dressler et al. (1994).  The outcome of these investigations is that the Butcher–Oemler effect is widespread in rich clusters at z > 0.2 and is due to vigorous episodes of star formation in a subset of the cluster members.

text: Observational evidence for this galaxy was presented in 2015, based on the claimed discovery of four, Cepheid variable stars by Sukanya Chakrabarti (RIT) and collaborators. Search for the stars was motivated by an earlier study  that linked a warp in the HI (atomic hydrogen) disk of the Milky Way Galaxy to the tidal effects of a perturbing galaxy. The unseen perturber's mass was calculated to be about 1% of that of the Milky Way, which would make it the third heaviest satellite of the Milky Way, after the Magellanic Clouds (LMC and SMC, each some 10x larger than Galaxy X). In this theoretical model, the putative satellite galaxy would have interacted with the Milky Way some 600 million years ago, coming as close as , and would now be on its way away from the Milky Way.

text: Observational evidence for this galaxy was presented in 2015, based on the claimed discovery of four, Cepheid variable stars by Sukanya Chakrabarti

text: (RIT)

text: and collaborators. Search for the stars was motivated by an earlier study  that linked a warp in the HI (atomic hydrogen) disk of the Milky Way Galaxy to the tidal effects of a perturbing galaxy. The unseen perturber's mass was calculated to be about 1% of that of the Milky Way, which would make it the third heaviest satellite of the Milky Way, after the

text: Magellanic Clouds

text: (LMC and SMC, each some 10x larger than Galaxy X). In this theoretical model, the putative satellite galaxy would have interacted with the Milky Way some 600 million years ago, coming as close as , and would now be on its way away from the Milky Way.

text: Andromeda Galaxy appears to have significantly more common stars than the Milky Way, seeming to predominate the old stars with ages >7 years. The estimated luminosity of Andromeda Galaxy, , is about 25% higher than that of our own galaxy. However, the galaxy has a high inclination as seen from Earth and its interstellar dust absorbs an unknown amount of light, so it is difficult to estimate its actual brightness and other authors have given other values for the luminosity of the Andromeda Galaxy (including to propose it is the second brightest galaxy within a radius of 10 mega parsecs of the Milky Way, after the Sombrero Galaxy, with an absolute magnitude of around -22.21 or close)

text: Andromeda Galaxy appears to have significantly more common stars than the Milky Way, seeming to predominate the old stars with ages >7 years. The estimated

text: luminosity

text: of Andromeda Galaxy, , is about 25% higher than that of our own galaxy. However, the galaxy has a high

text: inclination

text: as seen from Earth and its

text: interstellar dust

text: absorbs an unknown amount of light, so it is difficult to estimate its actual brightness and other authors have given other values for the luminosity of the Andromeda Galaxy (including to propose it is the second brightest galaxy within a radius of 10

text: mega

text: parsec

text: s of the Milky Way, after the

text: Sombrero Galaxy

text: , with an absolute magnitude of around -22.21 or close)

text: In all methods the size is an indirect measure, obtained by a model that transforms, in abstract way, the real particle shape into a simple and standarized shape, like a sphere (the most usual) or a cuboid (when minimum bounding box is used), where the size parameter (ex. diameter of sphere) makes sense.  Exception is the mathematical morphology approach, where no shape hypothesis is necessary.

text: In all methods the size is an indirect measure, obtained by a model that transforms, in abstract way, the real particle shape into a simple and standarized shape, like a sphere (the most usual) or a

text: cuboid

text: (when

text: minimum bounding box

text: is used), where the size parameter (ex. diameter of sphere) makes sense.  Exception is the

text: mathematical morphology approach

text: , where no shape hypothesis is necessary.

text: Although the description of the objects in this category implies that the galaxies are separating apart, most of these galaxies are merging. Many of the objects have very pronounced tidal tails and bridges that have formed as a consequence of the interaction. Most objects are in the early stages of the merging process, where the galaxies still appear to have distinct nuclei and distinct (albeit distorted) disks. Among the most notable galaxies in this category are the Antennae Galaxies (NGC 4038 and NGC 4039, Arp 244) and the Mice Galaxies (NGC 4676, Arp 242).

text: Although the description of the objects in this category implies that the galaxies are separating apart, most of these galaxies are merging. Many of the objects have very pronounced tidal tails and bridges that have formed as a consequence of the interaction. Most objects are in the early stages of the merging process, where the galaxies still appear to have distinct nuclei and distinct (albeit distorted) disks. Among the most notable galaxies in this category are the

text: Antennae Galaxies

text: (NGC 4038 and NGC 4039, Arp 244) and the

text: Mice Galaxies

text: (NGC 4676, Arp 242).

text: The northern main spiral arm contains four large HII regions, while the southern arm has greater concentrations of young, hot stars. The estimated rate of supernova explosions in the Triangulum Galaxy is 0.06 Type Ia and 0.62 Type Ib/Type II per century. This is equivalent to a supernova explosion every 147 years, on average. As of 2008, a total of 100 supernova remnants have been identified in the Triangulum Galaxy, the majority of which lies in the southern half of the spiral galaxy. Similar asymmetries exist for H I and H II regions, plus highly luminous concentrations of massive, O type stars. The center of the distribution of these features is offset about two arc minutes to the southwest. M33 being a local galaxy, the Central Bureau for Astronomical Telegrams (CBAT) tracks novae in it along with M31 and M81.

text: The northern main spiral arm contains four large

text: HII region

text: s, while the southern arm has greater concentrations of young, hot stars. The estimated rate of

text: supernova

text: explosions in the Triangulum Galaxy is 0.06

text: Type Ia

text: and 0.62

text: Type Ib

text: Type II

text: per century. This is equivalent to a supernova explosion every 147 years, on average. As of 2008, a total of 100

text: supernova remnant

text: s have been identified in the Triangulum Galaxy, the majority of which lies in the southern half of the spiral galaxy. Similar asymmetries exist for H I and H II regions, plus highly luminous concentrations of massive,

text: O type stars

text: . The center of the distribution of these features is offset about two arc minutes to the southwest. M33 being a local galaxy, the

entity_name: Central Bureau for Astronomical Telegrams

text: Central Bureau for Astronomical Telegrams

text: (CBAT) tracks

text: nova

text: e in it along with M31 and

text: An estimation of the galaxy's span resulted in a conclusion of 150,000 light years, which is slightly larger than the Milky Way.

text: An estimation of the galaxy's span resulted in a conclusion of 150,000

text: light year

text: s, which is slightly larger than the Milky Way.

text: The size and shape of a cooking vessel is typically determined by how it will be used. Cooking vessels are typically referred to as "pots" and "pans," but there is great variation in their actual shapes. Most cooking vessels are roughly cylindrical.

text: The size and shape of a cooking vessel is typically determined by how it will be used. Cooking vessels are typically referred to as "pots" and "pans," but there is great variation in their actual shapes. Most cooking vessels are roughly

text: cylindrical

text: The 25 target galaxies are chosen to be representative (i.e. cover the range of basic galaxy parameters and environments) of nearby (distance < 27 Mpc) early type (E and S0) galaxies. The survey also includes 3 `bonus’ galaxies which have been observed during times that the main sample galaxies are not available. All galaxies are accessible from the northern hemisphere. Although only a small sample, the data reach to large galactocentric radii with excellent velocity resolution and S/N compared to other surveys.

text: The 25 target galaxies are chosen to be representative (i.e. cover the range of basic galaxy parameters and environments) of nearby (distance < 27 Mpc) early type (E and S0) galaxies. The survey also includes 3 `bonus’ galaxies which have been observed during times that the main sample galaxies are not available. All galaxies are accessible from the northern hemisphere. Although only a small sample, the data reach to large galactocentric radii with excellent velocity resolution and

text: S/N

text: compared to other surveys.

text: The morphological type of NGC 5238 has been the subject of some controversy. In 1979, the galaxy was classified as a barred spiral galaxy. Soon after, in 1984, the galaxy was included in a study of blue compact dwarf galaxies, incompatible with the classification of a barred spiral. However, the barred spiral classification was considered the correct classification for years. It was not until the mid 1990s that the galaxy was first recognized as a dwarf irregular galaxy. Even after this, the majority of studies recognized the galaxy as a spiral galaxy until 2015, when the classification of irregular finally became widely accepted

text: The morphological type of NGC 5238 has been the subject of some controversy. In 1979, the galaxy was classified as a

text: barred spiral

text: galaxy. Soon after, in 1984, the galaxy was included in a study of

text: blue compact dwarf

text: galaxies, incompatible with the classification of a barred spiral. However, the barred spiral classification was considered the correct classification for years. It was not until the mid 1990s that the galaxy was first recognized as a

text: dwarf irregular galaxy

text: . Even after this, the majority of studies recognized the galaxy as a spiral galaxy until 2015, when the classification of irregular finally became widely accepted

text: A Supercluster is a  large group of smaller galaxy clusters or galaxy groups, which is among the largest-known structures of the cosmos. The Milky Way is part of the Local Group galaxy cluster (that contains more than 54 galaxies), which in turn is part of the Laniakea Supercluster. This supercluster spans over 500 million light-years, while the Local Group spans over 10 million light-years. The number of superclusters in the observable universe is estimated to be 10 million.

text: A Supercluster is a  large group of smaller

text: galaxy cluster

text: s or

text: galaxy group

text: s, which is among the

text: largest-known structures

text: of the

text: cosmos

text: . The

text: Milky Way

text: is part of the

text: Local Group

text: galaxy cluster

text: (that contains more than 54 galaxies), which in turn is part of the

text: Laniakea Supercluster

text: . This supercluster spans over 500 million

text: light-year

text: s, while the Local Group spans over 10 million light-years. The number of superclusters in the observable universe is estimated to be 10 million.

text: Approximately 77% of observed galaxies are spiral galaxies, two-thirds of all spiral galaxies are barred, and more than half, like the Milky Way, exhibit multiple arms. What makes our galaxy different, according to Rare Earth, is that it is unusually quiet and dim (see argument below), representing just 7% of its kind. Even so, this would still represent more than 200 billion galaxies in the known universe.

text: The first intergalactic stars were discovered in the Virgo cluster of galaxies. These stars form a massive group approximately 300,000 light years away from the nearest galaxy.

text: The first intergalactic stars were discovered in the Virgo cluster of galaxies. These stars form a massive group approximately 300,000

text: light year

text: s away from the nearest galaxy.

text: The galaxy is inclined an estimated 77° relative to the Earth (where an angle of 90° would be viewed directly from the side). Analysis of the cross-sectional shape of the galaxy appears to demonstrate a pronounced, S-shaped warp, rather than just a flat disk. A possible cause of such a warp could be gravitational interaction with the satellite galaxies near the Andromeda Galaxy. The galaxy M33 could be responsible for some warp in Andromeda's arms, though more precise distances and radial velocities are required.

text: The galaxy is inclined an estimated 77° relative to the Earth (where an angle of 90° would be viewed directly from the side). Analysis of the cross-sectional shape of the galaxy appears to demonstrate a pronounced, S-shaped warp, rather than just a flat disk. A possible cause of such a warp could be gravitational interaction with the satellite galaxies near the Andromeda Galaxy. The galaxy

text: could be responsible for some warp in Andromeda's arms, though more precise distances and radial velocities are required.

text: Patterns, sometimes called developments, show the size and shape of a flat piece of material needed for later bending or folding into a three dimensional shape.

text: The "Hurry-Scurry Galaxy" in the videogame Super Mario Galaxy has a planet in the similar shape of a rhombicuboctahedron.

text: The "Hurry-Scurry Galaxy" in the videogame

text: Super Mario Galaxy

text: has a planet in the similar shape of a rhombicuboctahedron.

text: In irregular galaxies, open clusters may be found throughout the galaxy, although their concentration is highest where the gas density is highest. Open clusters are not seen in elliptical galaxies: star formation ceased many millions of years ago in ellipticals, and so the open clusters which were originally present have long since dispersed.

text: In

text: irregular galaxies

text: , open clusters may be found throughout the galaxy, although their concentration is highest where the gas density is highest. Open clusters are not seen in

text: elliptical galaxies

text: : star formation ceased many millions of years ago in ellipticals, and so the open clusters which were originally present have long since dispersed.

text: In astronomy, a blue compact dwarf galaxy (BCD galaxy) is a small galaxy which contains large clusters of young, hot, massive stars. These stars, the brightest of which are blue, cause the galaxy itself to appear blue in colour. Most BCD galaxies are also classified as dwarf irregular galaxies or as dwarf lenticular galaxies. Because they are composed of star clusters, BCD galaxies lack a uniform shape. They consume gas intensely, which causes their stars to become very violent when forming.

text: In

text: astronomy

text: , a blue compact dwarf galaxy (BCD galaxy) is a small galaxy which contains large

text: clusters

text: of young, hot, massive

text: star

text: s. These stars, the brightest of which are blue, cause the galaxy itself to appear

text: blue

text: in colour. Most BCD galaxies are also classified as dwarf

text: irregular galaxies

text: or as dwarf

text: lenticular galaxies

text: . Because they are composed of star clusters, BCD galaxies lack a uniform shape. They consume gas intensely, which causes their stars to become very violent when forming.

text: Around 200,000 light years in diameter, NGC 772 is twice the size of the Milky Way Galaxy, and is surrounded by several satellite galaxies – including the dwarf elliptical, NGC 770 – whose tidal forces on the larger galaxy have likely caused the emergence of a  single elongated outer spiral arm that is much more developed than the others arms. Halton Arp includes NGC 772 in his Atlas of Peculiar Galaxies as Arp 78, where it is described as a "Spiral galaxy with a small high-surface brightness companion".

text: Around 200,000 light years in diameter, NGC 772 is twice the size of the

text: Milky Way Galaxy

text: , and is surrounded by several

text: satellite galaxies

text: – including the dwarf

text: elliptical

text: NGC 770

text: – whose

text: tidal force

text: s on the larger galaxy have likely caused the emergence of a  single elongated outer

text: spiral arm

text: that is much more developed than the others arms.

text: Halton Arp

text: includes NGC 772 in his

text: Atlas of Peculiar Galaxies

text: as

entity_section: Spiral galaxies with small high surface brightness companions

text: Arp 78

text: , where it is described as a "Spiral galaxy with a small high-

text: surface brightness

text: companion".

text: The resulting energy wave broke Replicator Carter and all her brethren into their constituent parts, finally ending the threat of Replicator Carter and her race once and for all although her actions had life-changing consequences for the entire Milky Way galaxy and its people.

text: According to the lead programmer of the 16 bit Amiga/Atari ST and the MSX conversions Rob Nicholson, he did not have access to the source code because of contractual issues and had to write them "blind". All he had were the ship shapes and the procedural generation code for the galaxies.

text: According to the lead programmer of the 16 bit Amiga/Atari ST and the MSX conversions Rob Nicholson, he did not have access to the

text: source code

text: because of contractual issues and had to write them "blind". All he had were the ship shapes and the procedural generation code for the galaxies.

text: NGC 5545 is a spiral galaxy in the northern constellation of Boötes. It is interacting with the spiral galaxy NGC 5544.

text: NGC 5545 is a

text: spiral galaxy

text: in the northern

text: constellation

text: of

text: Boötes

text: . It is interacting with the spiral galaxy

text: NGC 5544

text: In 2005, astronomers from the University of Wisconsin at Madison and Whitewater determined, on the basis of 400 hours of observation on the Spitzer Space Telescope, that the Milky Way galaxy has a more substantial bar structure across its core than previously recognized.

text: In 2005, astronomers from the

text: University of Wisconsin

text: at

text: Madison

text: and

text: Whitewater

text: determined, on the basis of 400 hours of observation on the Spitzer Space Telescope, that the

text: Milky Way

text: galaxy has a more substantial

text: bar structure

text: across its core than previously recognized.

text: NGC 3109 is classified as a Magellanic type irregular galaxy, but it may in fact be a small spiral galaxy. If it is a spiral galaxy, it would be the smallest in the Local Group.NGC 3109 has a mass of about 2.3×10 times the mass of the Sun, of which 20% is in the form of neutral hydrogen. It is oriented edge-on from our point of view, and may contain a disk and a halo. The disk appears to be composed of stars of all ages, whereas the halo contains only very old and metal-poor stars. NGC 3109 does not appear to possess a galactic nucleus.

text: NGC 3109 is classified as a

text: Magellanic

text: type

text: irregular galaxy

text: , but it may in fact be a small

text: spiral galaxy

text: . If it is a spiral galaxy, it would be the smallest in the Local Group.NGC 3109 has a mass of about 2.3×10 times the mass of the

text: Sun

text: , of which 20% is in the form of neutral

text: hydrogen

text: . It is oriented edge-on from our point of view, and may contain a

text: disk

text: and a

text: halo

text: . The disk appears to be composed of stars of all ages, whereas the halo contains only very old and

text: metal-poor

text: stars. NGC 3109 does not appear to possess a galactic nucleus.

text: The Milky Way galaxy and the nearby Andromeda Galaxy are moving toward each other at about 130 km/s, and—depending upon the lateral movements—the two might collide in about five to six billion years. Although the Milky Way has never collided with a galaxy as large as Andromeda before, evidence of past collisions of the Milky Way with smaller dwarf galaxies is increasing.

text: The Milky Way galaxy and the nearby Andromeda Galaxy are moving toward each other at about 130

text: km/s

text: , and—depending upon the lateral movements—the two might collide in about five to six billion years. Although the Milky Way has never collided with a galaxy as large as Andromeda before, evidence of past collisions of the Milky Way with smaller dwarf galaxies is increasing.

text: Launched at the 1970 São Paulo Auto Show, the Ford Landau was a full-size car, manufactured in Brazil from 1971 until 1983 by Ford Brasil at their São Paulo facility. It became Ford's flagship in that country. It was based on the U.S. 1966 Ford Galaxie.  It was only offered as a 4-door sedan, although the American version was offered in a wide variety of bodysyles.  After 1976, it gained more differences from the Galaxie and LTD, and featured the newly introduced 302 engine, a lighter 5.0L V8, and its radical restyling clearly resembling the 1965 Lincoln Continental.

text: Launched at the 1970 São Paulo Auto Show, the Ford Landau was a full-size

text: car

text: , manufactured in Brazil from 1971 until 1983 by

text: Ford Brasil

text: at their

text: São Paulo

text: facility. It became Ford's flagship in that country. It was based on the U.S. 1966

text: Ford Galaxie

text: .  It was only offered as a 4-door sedan, although the American version was offered in a wide variety of bodysyles.  After 1976, it gained more differences from the Galaxie and LTD, and featured the newly introduced 302 engine, a lighter 5.0L V8, and its radical restyling clearly resembling the 1965

text: Lincoln Continental

text: Other possible members galaxies (galaxies listed in only one or two of the lists from the above references) include the irregular galaxies NGC 5238 and UGC 8508.

text: Other possible members galaxies (galaxies listed in only one or two of the lists from the above references) include the

text: irregular galaxies

text: NGC 5238

text: and

text: UGC 8508

text: Edwin Hubble classified spiral galaxies of this type as "SB" (spiral, barred) in his Hubble sequence, and arranged them into sub-categories based on how open the arms of the spiral are. SBa types feature tightly bound arms, while SBc types are at the other extreme and have loosely bound arms. SBb-type galaxies lie in between. SB0 is a barred lenticular galaxy. A new type, SBm, was subsequently created to describe somewhat irregular barred spirals, such as the Magellanic Cloud galaxies, which were once classified as irregular galaxies, but have since been found to contain barred spiral structures. Among other types in Hubble's classifications for the galaxies are: spiral galaxy, elliptical galaxy and irregular galaxy.

text: Edwin Hubble

text: classified spiral galaxies of this type as "SB" (spiral, barred) in his

text: Hubble sequence

text: , and arranged them into sub-categories based on how open the arms of the spiral are. SBa types feature tightly bound arms, while SBc types are at the other extreme and have loosely bound arms. SBb-type galaxies lie in between. SB0 is a barred

text: lenticular galaxy

text: . A new type, SBm, was subsequently created to describe somewhat

text: irregular

text: barred spirals, such as the

text: Magellanic Cloud galaxies

text: , which were once classified as irregular galaxies, but have since been found to contain barred spiral structures. Among other types in Hubble's classifications for the galaxies are:

text: spiral galaxy

text: elliptical galaxy

text: and

text: irregular galaxy

text: In 1932, Jan Hendrik Oort became the first to report that measurements of the stars in the Solar neighborhood moved faster than expected when a mass distribution based upon visible matter was assumed, but this measurement was later determined to be essentially erroneous. In 1939, Horace Babcock reported in his PhD thesis measurements of the rotation curve for Andromeda which suggested that the mass-to-luminosity ratio increases radially. He attributed that to either the absorption of light within the galaxy or to modified dynamics in the outer portions of the spiral and not to any form of missing matter. In 1959, Louise Volders demonstrated that spiral galaxy M33 does not spin as expected according to Keplerian dynamics. In the late 1960s and early 1970s, Vera Rubin, an astronomer at the Department of Terrestrial Magnetism at the Carnegie Institution of Washington worked with a new sensitive spectrograph that could measure the velocity curve of edge-on spiral galaxies to a greater degree of accuracy than had ever before been achieved. Together with fellow staff-member Kent Ford, Rubin announced at a 1975 meeting of the American Astronomical Society the discovery that most stars in spiral galaxies orbit at roughly the same speed, and that this implied that galaxy masses grow approximately linearly with radius well beyond the location of most of the stars (the galactic bulge).  Rubin presented her results in an influential paper in 1980. These were the first robust results to suggest that either Newtonian gravity does not apply universally or that, conservatively, upwards of 50% of the mass of galaxies was contained in the relatively dark galactic halo. Although initially met with skepticism,  Rubin's results have been confirmed over the subsequent decades.

text: In 1932,

text: Jan Hendrik Oort

text: became the first to report that measurements of the stars in the

text: Solar neighborhood

text: moved faster than expected when a mass distribution based upon visible matter was assumed, but this measurement was later determined to be essentially erroneous. In 1939,

text: Horace Babcock

text: reported in his PhD thesis measurements of the rotation curve for Andromeda which suggested that the mass-to-luminosity ratio increases radially. He attributed that to either the absorption of light within the galaxy or to modified dynamics in the outer portions of the spiral and not to any form of missing matter. In 1959, Louise Volders demonstrated that spiral galaxy

text: does not spin as expected according to

text: Keplerian dynamics

text: . In the late 1960s and early 1970s,

text: Vera Rubin

text: , an astronomer at the Department of Terrestrial Magnetism at the

text: Carnegie Institution of Washington

text: worked with a new sensitive

text: spectrograph

text: that could measure the velocity curve of edge-on

text: spiral galaxies

text: to a greater degree of accuracy than had ever before been achieved. Together with fellow staff-member

text: Kent Ford

text: , Rubin announced at a 1975 meeting of the

text: American Astronomical Society

text: the discovery that most

text: star

text: s in

text: spiral galaxies

text: orbit at roughly the same speed, and that this implied that galaxy masses grow approximately linearly with radius well beyond the location of most of the stars (the

text: galactic bulge

text: ).  Rubin presented her results in an influential paper in 1980. These were the first robust results to suggest that either

text: Newtonian gravity

text: does not apply universally or that, conservatively, upwards of 50% of the mass of galaxies was contained in the relatively dark galactic halo. Although initially met with skepticism,  Rubin's results have been confirmed over the subsequent decades.

text: Messier 74 (also known as NGC 628) is a  spiral galaxy in the constellation Pisces. It is at a distance of about 32 million light-years away from Earth. The galaxy contains two clearly defined spiral arms and is therefore used as an archetypal example of a grand design spiral galaxy.  The galaxy's low surface brightness makes it the most difficult Messier object for amateur astronomers to observe.  However, the relatively large angular size of the galaxy and the galaxy's face-on orientation make it an ideal object for professional astronomers who want to study spiral arm structure and spiral density waves. It is estimated that M74 is home to about 100 billion stars.

text: Messier 74 (also known as NGC 628) is a

text: spiral galaxy

text: in the

text: constellation

text: Pisces

text: . It is at a distance of about 32 million light-years away from Earth. The galaxy contains two clearly defined

text: spiral arm

text: s and is therefore used as an archetypal example of a

text: grand design spiral galaxy

text: .  The galaxy's low surface brightness makes it the most difficult

text: Messier object

text: for amateur astronomers to observe.  However, the relatively large angular size of the galaxy and the galaxy's face-on orientation make it an ideal object for professional astronomers who want to study

text: spiral arm

text: structure and

text: spiral density waves

text: . It is estimated that M74 is home to about 100 billion stars.

text: Gestaltzerfall (German for "shape decomposition") refers to a type of visual agnosia and is a psychological phenomenon where delays in recognition are observed when a complex shape is stared at for a while as the shape seems to decompose into its constituting parts. With regards to kanji, a study has shown that delays are most significant when the characters are of the same size. When characters to recognize are of different sizes, delays are observed only when they are of different patterns.

text: Gestaltzerfall (German for "shape decomposition") refers to a type of

text: visual agnosia

text: and is a

text: psychological

text: phenomenon where delays in recognition are observed when a complex shape is stared at for a while as the shape seems to decompose into its constituting parts. With regards to

text: kanji

text: , a study has shown that delays are most significant when the characters are of the same size. When characters to recognize are of different sizes, delays are observed only when they are of different patterns.

text: Shapes of physical objects are equal if the subsets of space these objects occupy satisfy the definition above. In particular, the shape does not depend on the size and placement in space of the object. For instance, a "

text: X-shaped (or "winged") radio galaxies are a class of extragalactic radio source that exhibit two, low-surface-brightness radio lobes (the "wings") oriented at an angle to the active, or high-surface-brightness, lobes. Both sets of lobes pass symmetrically through the center of the elliptical galaxy that is the source of the lobes, giving the radio galaxy an X-shaped morphology as seen on radio maps (see figure).

text: X-shaped (or "winged") radio galaxies are a class of extragalactic

text: radio source

text: that exhibit two, low-surface-brightness radio lobes (the "wings") oriented at an angle to the active, or high-surface-brightness, lobes. Both sets of lobes pass symmetrically through the center of the

text: elliptical galaxy

text: that is the source of the lobes, giving the

text: radio galaxy

text: an X-shaped morphology as seen on radio maps (see figure).

text: Circinus also houses ESO 97-G13, commonly known as the Circinus Galaxy. Discovered in 1977, it is a relatively unobscured galaxy (magnitude 10.6), which is unusual for galaxies located in constellations near the Milky Way, since their dim light is obscured by gas and dust. This oblong spiral galaxy with 6.9 by 3.0 arcminutes and 26,000 light-years in diameter, is located 13 million light-years away from Earth and lies 4 degrees off the galactic plane. It is the closest Seyfert galaxy to the Milky Way, and therefore hosts an active galactic nucleus.

text: Circinus also houses ESO 97-G13, commonly known as the

text: Circinus Galaxy

text: . Discovered in 1977, it is a relatively unobscured galaxy (magnitude 10.6), which is unusual for galaxies located in constellations near the

text: Milky Way

text: , since their dim light is obscured by gas and dust. This oblong

text: spiral galaxy

text: with 6.9 by 3.0 arcminutes and 26,000 light-years in diameter, is located 13 million light-years away from Earth and lies 4 degrees off the

text: galactic plane

text: . It is the closest

text: Seyfert galaxy

text: to the Milky Way, and therefore hosts an

text: active galactic nucleus

text: In 1963, Dick Brannan set the NHRA Super/Stock National record at 12.42 on a hot July day. In the biggest race of the year, the INDY Nationals, Ed Martin's lightweight Galaxie lost the Super Stock trophy run to John Barker's Dodge but at the teardown, the Dodge was found to have an illegal cam. In drag racing, the 427 Ford Galaxie was a winner in three consecutive National Events: the '64 Indy Nationals, the 1965 WinterNationals and the 1965 Indy Nationals.  It was Mike Schmitt driving the Desert Motors Galaxie to the AA/SA Class win at the 1964 Indy Nationals. At the 1965 Winternationals it was a clean sweep as Doug Butler's four-speed took the win in AA/S with a 12.77 @ 114.21 and Bill Hanyon won on the automatic side with a 12.24 @ 117.95. Additionally, Bud Schellenberger's "Double A Stock" 1964 Galaxie was the 1965 Indy Nationals Top Stock Eliminator with a 12.16 @ 114.21. The Shelby Super Snake top fuel dragster, powered by a 427 supercharged SOHC, became the first car in NHRA competition to break the six-second quarter-mile time barrier.  It was the winner of the 1966 NHRA Spring Nationals. In every decade since, the FE has held drag-racing records. In 2011, the new decade opens with the NHRA SS/F (class rules include stock compression ratio, stock valve sizes, stock carb sizing and other OEM-type equipment limitations) national record:  the quartermile in 9.29 seconds, with a closing speed of 143.63 mph.

text: OEM

text: -type equipment limitations) national record:  the quartermile in 9.29 seconds, with a closing speed of 143.63 mph.

text: NGC 93 (PGC 1412) is an interacting spiral galaxy located in Andromeda constellation. The galaxy is 100 thousand light-years across and was discovered by R. J. Mitchell in 1854. The galaxy is currently interacting with NGC 90, a nearby large spiral galaxy.

text: NGC 93 (PGC 1412) is an interacting

text: spiral galaxy

text: located in

text: Andromeda constellation

text: . The

text: galaxy

text: is 100 thousand light-years across and was discovered by R. J. Mitchell in 1854. The galaxy is currently interacting with

text: NGC 90

text: , a nearby large spiral galaxy.

text: The archetype of such a colliding-wind binary system is WR140 (HD 193793), which consists of a 20 solar mass () Wolf-Rayet star orbiting about a , spectral class O4-5 main sequence star every 7.9 years. The high orbital eccentricity of the pair allows astronomers to observe changes the colliding winds as their separation varies. Another prominent example of a colliding-wind binary is thought to be Eta Carinae, one of the most luminous objects in the Milky Way galaxy. The first colliding-wind binary to be detected in the X-ray band outsidethe Milky Way galaxy was HD 5980, located in the Small Magellanic Cloud.

text: The archetype of such a colliding-wind binary system is

text: (HD 193793), which consists of a 20

text: solar mass

text: Wolf-Rayet star

text: orbiting about a ,

text: spectral class

text: O4-5 main sequence star

text: every 7.9 years. The high

text: orbital eccentricity

text: of the pair allows astronomers to observe changes the colliding winds as their separation varies. Another prominent example of a colliding-wind binary is thought to be

text: Eta Carinae

text: , one of the most luminous objects in the

text: Milky Way

text: galaxy. The first colliding-wind binary to be detected in the X-ray band outsidethe Milky Way galaxy was

text: HD 5980

text: , located in the

text: Small Magellanic Cloud

text: The horror-based story, which ties into the Shadow/Vorlon plotline, centers on the return of an ancient and overwhelming alien force which had once attempted to destroy life in the Milky Way Galaxy.

text: The horror-based story, which ties into the Shadow/Vorlon plotline, centers on the return of an ancient and overwhelming alien force which had once attempted to destroy life in the

text: Milky Way Galaxy

text: Canes Venatici contains five Messier objects, including four galaxies. One of the more significant galaxies in Canes Venatici is the Whirlpool Galaxy (M51, NGC 5194) and NGC 5195, a small barred spiral galaxy that is seen face on. This was the first galaxy recognised as having a spiral structure, this structure being first observed by Lord Rosse in 1845. It is a face-on spiral galaxy 37 million light-years from Earth. Widely considered to be one of the most beautiful galaxies visible, M51 has many star-forming regions and nebulae in its arms, coloring them pink and blue in contrast to the older yellow core. M51 has a smaller companion, NGC 5195, that has very few star-forming regions and thus appears yellow. It is passing behind M51 and may be the cause of the larger galaxy's prodigious star formation.

text: Canes Venatici contains five

text: Messier object

text: s, including four

text: galaxies

text: . One of the more significant galaxies in Canes Venatici is the

text: Whirlpool Galaxy

text: (M51, NGC 5194) and

text: NGC 5195

text: , a small barred

text: spiral galaxy

text: that is seen face on. This was the first galaxy recognised as having a spiral structure, this structure being first observed by

text: Lord Rosse

text: in 1845. It is a face-on spiral galaxy 37 million light-years from Earth. Widely considered to be one of the most beautiful galaxies visible, M51 has many

text: star-forming regions

text: and

text: nebula

text: e in its arms, coloring them pink and blue in contrast to the older yellow core. M51 has a smaller companion, NGC 5195, that has very few star-forming regions and thus appears yellow. It is passing behind M51 and may be the cause of the larger galaxy's prodigious star formation.

text: The rotational dynamics of galaxies are well characterized by their position on the Tully–Fisher relation, which shows that for spiral galaxies the rotational velocity is uniquely related to its total luminosity. A consistent way to predict the rotational velocity of a spiral galaxy is to measure its bolometric luminosity and then read its rotation rate from its location on the Tully–Fisher diagram. Conversely, knowing the rotational velocity of a spiral galaxy gives its luminosity. Thus the magnitude of the galaxy rotation is related to the galaxy's visible mass.

text: The rotational dynamics of galaxies are well characterized by their position on the

text: Tully–Fisher relation

text: , which shows that for spiral galaxies the rotational velocity is uniquely related to its total luminosity. A consistent way to predict the rotational velocity of a spiral galaxy is to measure its

text: bolometric luminosity

text: and then read its rotation rate from its location on the Tully–Fisher diagram. Conversely, knowing the rotational velocity of a spiral galaxy gives its luminosity. Thus the magnitude of the galaxy rotation is related to the galaxy's visible mass.

text: A pinwheel-shaped disk, rotating in a direction opposite to that of the galaxy, is found deep inside NGC 7252: it resembles a face-on spiral galaxy, yet it is only 10,000 light years across. It is believed that this pinwheel-shaped structure is a remnant of a collision between two galaxies. Within a few billion years, NGC 7252 will look like an elliptical galaxy with a small inner disk due to the exhaustion of the gases in the galaxy.

text: A majority of spiral galaxies, including our own Milky Way galaxy, have a linear, bar-shaped band of stars that extends outward to either side of the core, then merges into the spiral arm structure. In the Hubble classification scheme, these are designated by an SB, followed by a lower-case letter (a, b or c) that indicates the form of the spiral arms (in the same manner as the categorization of normal spiral galaxies). Bars are thought to be temporary structures that can occur as a result of a density wave radiating outward from the core, or else due to a tidal interaction with another galaxy. Many barred spiral galaxies are active, possibly as a result of gas being channeled into the core along the arms.

text: A majority of spiral galaxies, including our own

text: Milky Way

text: galaxy, have a linear, bar-shaped band of stars that extends outward to either side of the core, then merges into the spiral arm structure. In the Hubble classification scheme, these are designated by an SB, followed by a lower-case letter (a, b or c) that indicates the form of the spiral arms (in the same manner as the categorization of normal spiral galaxies). Bars are thought to be temporary structures that can occur as a result of a density wave radiating outward from the core, or else due to a

text: tidal interaction

text: with another galaxy. Many barred spiral galaxies are active, possibly as a result of gas being channeled into the core along the arms.

text: The Sculptor Galaxy, also known as the Silver Coin or Silver Dollar Galaxy, NGC 253, is an intermediate spiral galaxy in the constellation Sculptor.  The Sculptor Galaxy is a starburst galaxy, which means that it is currently undergoing a period of intense star formation.

text: The Sculptor Galaxy, also known as the Silver Coin or Silver Dollar Galaxy, NGC 253, is an

text: intermediate spiral galaxy

text: in the

text: constellation

text: Sculptor

text: .  The Sculptor Galaxy is a

text: starburst galaxy

text: , which means that it is currently undergoing a period of intense

text: star formation

text: The dwarf galaxy problem, also known as the missing satellites problem, arises from numerical cosmological simulations that predict the evolution of the distribution of matter in the universe. Dark matter seems to cluster hierarchically and in ever increasing number counts for smaller-and-smaller-sized halos. However, although there seem to be enough observed normal-sized galaxies to account for this distribution, the number of dwarf galaxies is orders of magnitude lower than expected from simulation. For comparison, there were observed to be around 38 dwarf galaxies in the Local Group, and only around 11 orbiting the Milky Way, (for a detailed and more up to date list see List of Milky Way's satellite galaxies) yet one dark matter simulation predicted around 500 Milky Way dwarf satellites.

text: The dwarf galaxy problem, also known as the missing satellites problem, arises from numerical

text: cosmological

text: simulation

text: s that predict the evolution of the distribution of

text: matter

text: in the

text: universe

text: Dark matter

text: seems to cluster hierarchically and in ever increasing number counts for smaller-and-smaller-sized

text: halos

text: . However, although there seem to be enough observed normal-sized

text: galaxies

text: to account for this distribution, the number of

text: dwarf galaxies

text: is

text: orders of magnitude

text: lower than expected from simulation. For comparison, there were observed to be around 38 dwarf galaxies in the

text: Local Group

text: , and only around 11 orbiting the

text: Milky Way

text: , (for a detailed and more up to date list see

text: List of Milky Way's satellite galaxies

text: ) yet one dark matter simulation predicted around 500 Milky Way dwarf satellites.

text: The biggest problem with Arp's analysis is that today there are hundreds of thousands of quasars with known redshifts discovered by various sky surveys. The vast majority of these quasars are not correlated in any way with nearby AGN. Indeed, with improved observing techniques, a number of host galaxies have been observed around quasars which indicates that those quasars at least really are at cosmological distances and are not the kind of objects Arp proposes. Arp's analysis, according to most scientists, suffers from being based on small number statistics and hunting for peculiar coincidences and odd associations. Unbiased samples of sources, taken from numerous galaxy surveys of the sky show none of the proposed 'irregularities', nor that any statistically significant correlations exist.

text: The biggest problem with Arp's analysis is that today there are hundreds of thousands of quasars with known redshifts discovered by various

text: sky surveys

text: . The vast majority of these quasars are not correlated in any way with nearby AGN. Indeed, with improved observing techniques, a number of host galaxies have been observed around quasars which indicates that those quasars at least really are at

text: cosmological distances

text: and are not the kind of objects Arp proposes. Arp's analysis, according to most scientists, suffers from being based on

text: small number statistics

text: and hunting for peculiar coincidences and odd associations. Unbiased samples of sources, taken from numerous

text: galaxy survey

text: s of the sky show none of the proposed 'irregularities', nor that any

text: statistically significant

text: correlations exist.

text: The central elliptical cD galaxy of this cluster is undergoing a massive starburst, the highest recorded in a middle of a galaxy cluster, although other galaxies at higher redshifts have a higher starburst rate (see Baby Boom Galaxy).Observations by a variety of telescopes including the GALEX and Herschel space telescopes shows that it has been converting material to stars at an exceptionally high rate of 740  per year. This is considerably higher than that of NGC 1275 A, the central galaxy of the Perseus Cluster, where stars are formed at a rate around 20 times lower, or the one per year rate of star formation in the Milky Way.

text: The central elliptical cD galaxy of this cluster is undergoing a massive starburst, the highest recorded in a middle of a galaxy cluster, although other galaxies at higher redshifts have a higher starburst rate (see

text: Baby Boom Galaxy

text: ).Observations by a variety of telescopes including the

text: GALEX

text: and

text: Herschel

text: space telescopes shows that it has been converting material to stars at an exceptionally high rate of 740  per year. This is considerably higher than that of

text: NGC 1275

text: A, the central galaxy of the

text: Perseus Cluster

text: , where stars are formed at a rate around 20 times lower, or the one per year rate of star formation in the

text: Milky Way

text: This complex galaxy is inclined by an angle of about 53° to the line of sight from the Earth, which is oriented at a position angle of 172°. It is categorized as a double-barred spiral galaxy with a small inner bulge through the core along with an outer bulge. The nucleus displays a weak level of activity of the LINER2 type. Variations in ultraviolet emission from the core suggest the presence of a supermassive black hole. Estimates for the mass of this object range from  to  times the mass of the Sun.

text: This complex galaxy is inclined by an angle of about 53° to the line of sight from the

text: Earth

text: , which is oriented at a

text: position angle

text: of 172°. It is categorized as a double-barred spiral galaxy with a small inner bulge through the core along with an outer bulge. The nucleus displays a weak level of activity of the

entity_name: Low-ionization nuclear emission-line region

text: LINER

text: 2 type. Variations in

text: ultraviolet

text: emission from the core suggest the presence of a

text: supermassive black hole

text: . Estimates for the mass of this object range from  to  times the mass of the

text: Sun

text: The size and shape of any device is largely driven by the size and shape of the components used to make that device. Traditional HDDs and optical drives are designed around the rotating platter(s) or optical disc along with the spindle motor inside. If an SSD is made up of various interconnected integrated circuits (ICs) and an interface connector, then its shape is no longer limited to the shape of rotating media drives. Some solid state storage solutions come in a larger chassis that may even be a rack-mount form factor with numerous SSDs inside. They would all connect to a common bus inside the chassis and connect outside the box with a single connector.

text: The size and shape of any device is largely driven by the size and shape of the components used to make that device. Traditional HDDs and

text: optical drives

text: are designed around the rotating

text: platter

text: (s) or

text: optical disc

text: along with the

text: spindle motor

text: inside. If an SSD is made up of various interconnected

text: integrated circuit

text: s (ICs) and an interface connector, then its shape is no longer limited to the shape of rotating media drives. Some solid state storage solutions come in a larger chassis that may even be a rack-mount form factor with numerous SSDs inside. They would all connect to a common bus inside the chassis and connect outside the box with a single connector.

text: DDO 190 is small, but not tiny: about 15,000 light years across—about 1/6 the size of our galaxy. It is also well outside the Local Group, which contains nearby galaxies (the Andromeda galaxy is less than 3 million light years distant from Earth, for comparison), and is instead thought to be part of the M94 galaxy group. But if true it is fairly isolated even from the others on its team; the nearest neighbor appears to be another dwarf galaxy, DDO 187, at a distance of .

text: DDO 190 is small, but not tiny: about 15,000 light years across—about 1/6 the size of our galaxy. It is also well outside the

text: Local Group

text: , which contains nearby galaxies (the Andromeda galaxy is less than 3 million light years distant from Earth, for comparison), and is instead thought to be part of the

text: M94 galaxy group

text: . But if true it is fairly isolated even from the others on its team; the nearest neighbor appears to be another dwarf galaxy,

text: DDO 187

text: , at a distance of .

text: The dynamics of these objects, if they do exist, must be quite different from that of standard star clusters. With a very narrow mass range (all brown dwarfs or white dwarfs), the evaporation rate of these RAMBOs should be very slow as predicted by the evolution of simulated mono-component cluster models. Theoretically, these very long-lived objects could exist in large numbers. The presence of a clustered thick disk-like component of dark matter in the Galaxy has been suggested by Sanchez-Salcedo (1997, 1999) and Kerins (1997).

text: The dynamics of these objects, if they do exist, must be quite different from that of standard star clusters. With a very narrow mass range (all brown dwarfs or white dwarfs), the evaporation rate of these RAMBOs should be very slow as predicted by the evolution of simulated mono-component cluster models. Theoretically, these very long-lived objects could exist in large numbers. The presence of a clustered thick disk-like component of

text: dark matter

text: in the

text: Galaxy

text: has been suggested by Sanchez-Salcedo (1997, 1999) and Kerins (1997).

text: Day shapes are black in color and their sizes are determined by the ColRegs, for instance the size of the ball is not less than 0.6 meter diameter.  The vertical distance between shapes is at least 1.5 meters.  Vessels of less than 20 meters length may use shapes of smaller size commensurate with the size of the vessel. Day shapes of standard and reduced sizes are both commercially available. Day shapes are commonly constructed from a light weight frame covered with fabric and are designed to be collapsible for ease of storage.

text: DDO 210 (also known as Aquarius Dwarf or PGC 65367) is a dwarf irregular galaxy in the constellation of Aquarius. It is a member of the Local Group and lies 3.2 ± 0.2 million light years from our Milky Way.

text: DDO 210

text: (also known as

text: Aquarius

text: Dwarf

text: or

text: PGC

text: 65367) is a

text: dwarf irregular

text: galaxy

text: in the

text: constellation

text: of

text: Aquarius

text: . It is a member of the

text: Local Group

text: and lies 3.2

text: million

text: light years

text: from our

text: Milky Way

text: The Corona Borealis Supercluster is a supercluster located in the constellation Corona Borealis and the most prominent example of its kind in the Northern Celestial Hemisphere. Dense and compact compared with other superclusters, its mass has been calculated to lie somewhere between 0.6 and 12 × 10 solar masses (M⊙). It contains the galaxy clusters Abell 2056, Abell 2061, Abell 2065 (the most massive galaxy cluster within the supercluster), Abell 2067, Abell 2079, Abell 2089, and Abell 2092. Of these, Abell 2056, 2061, 2065, 2067 and A2089 are gravitationally bound and in the process of collapsing to form a massive cluster. This entity has an estimated mass of around 1 × 10 M⊙.  If there is inter-cluster mass present, then Abell 2092 may also be involved. It has been estimated to be 100 megaparsecs (330 million light-years) wide and 40 megaparsecs  (130 million light years)  deep. It has a redshift of 0.07, which is equivalent to a distance of around 265.5 megaparsecs (964 million light-years).

text: The Corona Borealis Supercluster is a

text: supercluster

text: located in the constellation

text: Corona Borealis

text: and the most prominent example of its kind in the

text: Northern Celestial Hemisphere

text: . Dense and compact compared with other superclusters, its mass has been calculated to lie somewhere between 0.6 and 12 × 10

text: solar mass

text: es (M⊙). It contains the galaxy clusters

text: Abell 2056

text: Abell 2061

text: Abell 2065

text: (the most massive galaxy cluster within the supercluster),

text: Abell 2067

text: Abell 2079

text: Abell 2089

text: , and

text: Abell 2092

text: . Of these, Abell 2056, 2061, 2065, 2067 and A2089 are gravitationally bound and in the process of collapsing to form a massive cluster. This entity has an estimated mass of around 1 × 10 M⊙.  If there is inter-cluster mass present, then Abell 2092 may also be involved. It has been estimated to be 100

text: megaparsecs

text: (330 million

text: light-year

text: s) wide and 40 megaparsecs  (130 million light years)  deep. It has a redshift of 0.07, which is equivalent to a distance of around 265.5 megaparsecs (964 million light-years).

text: The Milky Way was once considered an ordinary spiral galaxy. Astronomers first began to suspect that the Milky Way is a barred spiral galaxy in the 1990s. Their suspicions were confirmed by Spitzer Space Telescope observations in 2005, which showed that the Milky Way's central bar is larger than was previously suspected.

text: The

text: Milky Way

text: was once considered an ordinary spiral galaxy. Astronomers first began to suspect that the Milky Way is a barred spiral galaxy in the 1990s. Their suspicions were confirmed by

text: Spitzer Space Telescope

text: observations in 2005, which showed that the Milky Way's central bar is larger than was previously suspected.

text: Some examples are Messier 49 (elliptical), Messier 58 (spiral), Messier 59 (elliptical), Messier 60 (elliptical), Messier 61 (spiral), Messier 84 (lenticular), Messier 86 (lenticular), Messier 87 (elliptical and a famous radio source), Messier 89 (elliptical) and Messier 90 (spiral). A noted galaxy that is not part of the cluster is the Sombrero Galaxy (M104), an unusual spiral galaxy. It is located about 10° due west of Spica.

text: Some examples are

text: Messier 49

text: elliptical

text: Messier 58

text: spiral

text: Messier 59

text: (elliptical),

text: Messier 60

text: (elliptical),

text: Messier 61

text: (spiral),

text: Messier 84

text: lenticular

text: Messier 86

text: (lenticular),

text: Messier 87

text: (elliptical and a famous

text: radio source

text: Messier 89

text: (elliptical) and

text: Messier 90

text: (spiral). A noted galaxy that is not part of the cluster is the

text: Sombrero Galaxy

text: (M104), an unusual spiral galaxy. It is located about 10° due west of Spica.

text: NGC 176 is an open cluster located around 3.5 million light-years in the constellation Tucana. This cluster consists of several stars together with another galaxy making it one of the most fascinating galaxies among nearby galaxies. It was discovered on August 12, 1834 by John Herschel.

text: NGC

text: 176 is an open cluster located around 3.5 million light-years in the constellation

text: Tucana

text: . This cluster consists of several stars together with another galaxy making it one of the most fascinating galaxies among nearby galaxies. It was discovered on August 12, 1834 by

text: John Herschel

text: The current model for the universe, ɅCDM, indicates that galaxies tend to cluster and achieve a web-like structure over time. Under such models, the large majority of baryons entering a galactic halo do so along these cosmic filaments. 70% of the mass inflow at the virial radius is consistent with coming in along cosmic filaments in evolutionary models of the Milky Way. Given current observational limitations, the majority of the filaments feeding into the Milky Way are not visible in HI. Despite this, some gas clouds within the Galaxy's halo have lower metallicities than that of gas stripped from satellites, suggesting that the clouds are primordial material probably flowing in along the cosmic filaments. Gas of this type, detectable out to ~160,000 ly (50 kpc), largely becomes part of the hot halo, cools and condenses, and falls into the Galactic disk to serve in star formation.

text: The current model for the universe, ɅCDM, indicates that galaxies tend to cluster and achieve a web-like structure over time. Under such models, the large majority of baryons entering a galactic halo do so along these cosmic filaments. 70% of the mass inflow at the

entity_section: Galaxies and cosmology .28virial mass and radius.29

text: virial radius

text: is consistent with coming in along cosmic filaments in evolutionary models of the Milky Way. Given current observational limitations, the majority of the filaments feeding into the Milky Way are not visible in HI. Despite this, some gas clouds within the Galaxy's halo have lower metallicities than that of gas stripped from satellites, suggesting that the clouds are primordial material probably flowing in along the cosmic filaments. Gas of this type, detectable out to ~160,000 ly (50 kpc), largely becomes part of the hot halo, cools and condenses, and falls into the Galactic disk to serve in star formation.

text: This spiral galaxy is notably asymmetric.  The spiral arms on the south side of the galaxy are chaotic in appearance, whereas the spiral arms on the north side of the galaxy are very well-defined.  Also, the spiral arms on the south side of the disk extend twice as far from the galaxy's nucleus as the spiral arms on the north side.  Because of the fragmentary appearance of some of the spiral arms, this galaxy is classified as a flocculent galaxy.

text: This spiral galaxy is notably asymmetric.  The

text: spiral arm

text: s on the south side of the galaxy are chaotic in appearance, whereas the spiral arms on the north side of the galaxy are very well-defined.  Also, the spiral arms on the south side of the disk extend twice as far from the galaxy's

text: nucleus

text: as the spiral arms on the north side.  Because of the fragmentary appearance of some of the spiral arms, this galaxy is classified as a

text: flocculent galaxy

text: For a filter to be compatible with a coffee maker, the filter needs to be a specific shape and size.  Common in the US are cone-shaped filters #2, #4, and #6, as well as basket-shaped filters in an 8-12 cup size.

text: The number density of galaxies in the LS falls off with the square of the distance from its center near the Virgo Cluster, suggesting that this cluster is not randomly located. Overall, the vast majority of the luminous galaxies (less than absolute magnitude −13) are concentrated in a small number of clouds (groups of galaxy clusters). Ninety-eight percent can be found in the following 11 clouds (given in decreasing order of number of luminous galaxies): Canes Venatici, Virgo Cluster, Virgo II (southern extension), Leo II, Virgo III, Crater (NGC 3672), Leo I, Leo Minor (NGC 2841), Draco (NGC 5907), Antlia (NGC 2997) and NGC 5643. Of the luminous galaxies located in the disk, one third are in the Virgo Cluster, while the remainder are found in the Canes Venatici Cloud and Virgo II Cloud, plus the somewhat insignificant NGC 5643 Group. The luminous galaxies in the halo are also concentrated in a small number of clouds (94% in 7 clouds). This distribution indicates that "most of the volume of the supergalactic plane is a great void." A helpful analogy that matches the observed distribution is that of soap bubbles. Flattish clusters and superclusters are found at the intersection of bubbles, which are large, roughly spherical (on the order of 20–60 Mpc in diameter) voids in space.Long filamentary structures seem to predominate. An example of this is the Hydra-Centaurus Supercluster, the nearest supercluster to the LS, which starts at a distance of roughly 30 Mpc and extends to 60 Mpc.

text: The

text: number density

text: of galaxies in the LS falls off with the square of the distance from its center near the

text: Virgo Cluster

text: , suggesting that this cluster is not randomly located. Overall, the vast majority of the luminous galaxies (less than

text: absolute magnitude

text: −13) are concentrated in a small number of

text: clouds

text: (groups of

text: galaxy cluster

text: s). Ninety-eight percent can be found in the following 11 clouds (given in decreasing order of number of luminous galaxies):

text: Canes Venatici

text: , Virgo Cluster, Virgo II (southern extension), Leo II, Virgo III, Crater (NGC 3672), Leo I, Leo Minor (NGC 2841), Draco (NGC 5907), Antlia (NGC 2997) and NGC 5643. Of the luminous galaxies located in the disk, one third are in the Virgo Cluster, while the remainder are found in the Canes Venatici Cloud and Virgo II Cloud, plus the somewhat insignificant NGC 5643 Group. The luminous galaxies in the halo are also concentrated in a small number of clouds (94% in 7 clouds). This distribution indicates that "most of the volume of the supergalactic plane is a great void." A helpful analogy that matches the observed distribution is that of soap bubbles. Flattish clusters and

text: superclusters

text: are found at the intersection of bubbles, which are large, roughly spherical (on the order of 20–60

text: Mpc

text: in diameter) voids in space.Long filamentary structures seem to predominate. An example of this is the

text: Hydra-Centaurus Supercluster

text: , the nearest supercluster to the LS, which starts at a distance of roughly 30 Mpc and extends to 60 Mpc.

text: The Large Magellanic Cloud (LMC) is a satellite galaxy of the Milky Way. At a distance of 50 kiloparsecs (≈163,000 light-years), the LMC is the third-closest galaxy to the Milky Way, after the Sagittarius Dwarf Spheroidal (~ 16 kpc) and the putative Canis Major Dwarf Galaxy (~ 12.9 kpc, though its status as a galaxy is under dispute) lying closer to the center of the Milky Way. The LMC has a diameter of about  and a mass of approximately 10 billion Sun masses (10 solar masses), making it roughly 1/100 as massive as the Milky Way. The LMC is the fourth-largest galaxy in the Local Group, after the Andromeda Galaxy (M31), the Milky Way, and the Triangulum Galaxy (M33).

text: The Large Magellanic Cloud (LMC) is a

text: satellite galaxy

text: of the

text: Milky Way

text: . At a distance of 50

text: kiloparsecs

text: light-year

text: s), the LMC is the third-closest galaxy to the Milky Way, after the

text: Sagittarius Dwarf Spheroidal

text: (~ 16 kpc) and the

text: putative

text: Canis Major Dwarf Galaxy

text: (~ 12.9 kpc, though its status as a galaxy is under

text: dispute

text: ) lying closer to the center of the Milky Way. The LMC has a diameter of about  and a mass of approximately 10 billion Sun masses (10

text: solar mass

text: es), making it roughly 1/100 as massive as the Milky Way. The LMC is the fourth-largest galaxy in the

text: Local Group

text: , after the

text: Andromeda Galaxy

text: (M31), the Milky Way, and the

text: Triangulum Galaxy

text: The Canis Major Dwarf Galaxy (CMa Dwarf) or Canis Major Overdensity (CMa Overdensity) is a disputed dwarf irregular galaxy in the Local Group, located in the same part of the sky as the constellation Canis Major.

text: The Canis Major Dwarf Galaxy (CMa Dwarf) or Canis Major Overdensity (CMa Overdensity) is a disputed

text: dwarf irregular galaxy

text: in the

text: Local Group

text: , located in the same part of the sky as the

text: constellation

text: Canis Major

text: In 1997 and in Heidelberg Kroupa, together with Ulrich Bastian, took the first precise measurement of the spatial movement of two extragalactic systems. In 1997 he also discovered stellar-dynamic solutions for the satellite galaxies of the Milky Way without the need for exotic dark matter. His work implies a possible connection of the satellite galaxies with the Bulge of the Milky Way. This connection can be explained by a collision of the early Milky Way with another young galaxy during which the satellite galaxies formed as tidal dwarf galaxies about 11 Gyr ago. This is shown in a series of research papers with Manuel Metz and Marcel Pawlowski.

text: In 1997 and in Heidelberg Kroupa, together with Ulrich Bastian, took the first precise measurement of the spatial movement of two extragalactic systems. In 1997 he also discovered stellar-dynamic solutions for the

text: satellite galaxies of the Milky Way

text: without the need for exotic

text: dark matter

text: . His work implies a possible connection of the satellite galaxies with the Bulge of the Milky Way. This connection can be explained by a collision of the early Milky Way with another young galaxy during which the satellite galaxies formed as

text: tidal dwarf galaxies

text: about 11 Gyr ago. This is shown in a series of research papers with Manuel Metz and Marcel Pawlowski.

text:
Column 1: Name of the galaxy
Column 2: Right ascension for epoch J2000
Column 3: Declination for epoch J2000
Column 4: Blue apparent magnitude of the galaxy
Column 5: Galaxy type: E=Elliptical; S0=Lenticular; Sa, Sb, Sc, Sd=Spiral (degree of woundedness of spiral arms); SBa, SBb, SBc, SBd=Barred Spiral; SAB= Intermediate Spiral (between barred and unbarred); Sm, SBm, Irr=Irregular; (r),(rs)=Ring Structure
Column 6: Angular diameter of the galaxy (arcminutes)
Column 7: Diameter of the galaxy (thousands of light years)
Column 8: Recessional velocity (km/s) of the galaxy relative to the cosmic microwave background

text: Column 1: Name of the

text: galaxy

text: <br>Column 2:

text: Right ascension

text: for

text: epoch J2000

text: <br>Column 3:

text: Declination

text: for epoch J2000<br>Column 4: Blue

text: apparent magnitude

text: of the galaxy<br>Column 5:

text: Galaxy type

text: : E=Elliptical; S0=Lenticular; Sa, Sb, Sc, Sd=Spiral (degree of woundedness of spiral arms); SBa, SBb, SBc, SBd=Barred Spiral; SAB= Intermediate Spiral (between barred and unbarred); Sm, SBm, Irr=Irregular; (r),(rs)=Ring Structure<br>Column 6: Angular diameter of the galaxy (

text: arcminutes

text:
)
Column 7: Diameter of the galaxy (thousands of light years)
Column 8: Recessional velocity (km/s) of the galaxy relative to the

text: cosmic microwave background

text: An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way Galaxy, and many more are thought to exist. They are loosely bound by mutual gravitational attraction and become disrupted by close encounters with other clusters and clouds of gas as they orbit the galactic center. This can result in a migration to the main body of the galaxy and a loss of cluster members through internal close encounters. Open clusters generally survive for a few hundred million years, with the most massive ones surviving for a few billion years. In contrast, the more massive globular clusters of stars exert a stronger gravitational attraction on their members, and can survive for longer. Open clusters have been found only in spiral and irregular galaxies, in which active star formation is occurring.

text: An open cluster is a

text: group

text: of up to a few thousand

text: star

text: s that were formed from the same

text: giant molecular cloud

text: and have roughly the same age. More than 1,100 open clusters have been discovered within the

text: Milky Way Galaxy

text: , and many more are thought to exist. They are loosely bound by mutual

text: gravitational attraction

text: and become disrupted by close encounters with other clusters and clouds of gas as they orbit the galactic center. This can result in a migration to the main body of the galaxy and a loss of cluster members through internal close encounters. Open clusters generally survive for a few hundred million years, with the most massive ones surviving for a few billion years. In contrast, the more massive

text: globular cluster

text: s of stars exert a stronger gravitational attraction on their members, and can survive for longer. Open clusters have been found only in

text: spiral

text: and

text: irregular galaxies

text: , in which active

text: star formation

text: is occurring.

text: Elliptical galaxies (such as IC 1101) are among some of the largest known thus far. Their stars are on orbits that are randomly oriented within the galaxy (i.e. they are not rotating like disk galaxies). A distinguishing feature of elliptical galaxies is that the velocity of the stars does not necessarily contribute to flattening of the galaxy, such as in spiral galaxies. Elliptical galaxies have supermassive black holes at their center, and the mass of these black holes correlates with the galaxy’s mass.

text: Elliptical galaxies (such as

text: IC 1101

text: ) are among some of the largest known thus far. Their stars are on orbits that are randomly oriented within the galaxy (i.e. they are not rotating like disk galaxies). A distinguishing feature of elliptical galaxies is that the velocity of the stars does not necessarily contribute to flattening of the galaxy, such as in spiral galaxies. Elliptical galaxies have

text: supermassive black hole

text: s at their center, and the mass of these black holes correlates with the galaxy’s mass.

text: Maffei 1 is a giant elliptical galaxy classified as type E3 in the Hubble classification scheme. This means that it is slightly flattened, its semi-minor axis being 70% of its semi-major axis. Maffei 1 has also a boxy shape (E(b)3 type), while its central region (radius ≈ 34 pc) is deficient in light emission as compared to the r law, meaning that Maffei 1 is a core type elliptical. Both the boxy shape and the presence of an underluminous core are typical of intermediate to massive ellipticals.

text: Maffei 1 is a giant elliptical galaxy classified as type E3 in the

text: Hubble classification

text: scheme. This means that it is slightly flattened, its

text: semi-minor axis

text: being 70% of its

text: semi-major axis

text: . Maffei 1 has also a boxy shape (E(b)3 type), while its central region (radius ≈ 34 pc) is deficient in light emission as compared to the r law, meaning that Maffei 1 is a core type elliptical. Both the boxy shape and the presence of an underluminous core are typical of intermediate to massive ellipticals.

text: Some galaxies are irregular and do not have any well-defined disk. Even in the case of a barred spiral galaxy like the Milky Way, defining the galactic plane is slightly imprecise and arbitrary since the stars are not perfectly coplanar. In 1959 the IAU defined the position of the Milky Way's north galactic pole as exactly RA = , Dec =  in the then-used B1950 epoch; in the currently-used J2000 epoch, after precession is taken into account, its position is RA , Dec . This position is in Coma Berenices, near the bright star Arcturus; likewise, the south galactic pole lies in the constellation Sculptor.

text: Some galaxies are irregular and do not have any well-defined disk. Even in the case of a

text: barred spiral galaxy

text: like the Milky Way, defining the galactic plane is slightly imprecise and arbitrary since the stars are not perfectly coplanar. In 1959 the

text: IAU

text: defined the position of the Milky Way's north galactic pole as exactly

text: RA

text: Dec

text: =  in the then-used

text: epoch

text: ; in the currently-used

text: epoch, after

text: precession

text: is taken into account, its position is RA , Dec . This position is in

text: Coma Berenices

text: , near the bright

text: star

text: Arcturus

text: ; likewise, the south galactic pole lies in the

text: constellation

text: Sculptor

text: NGC 772 is a spiral galaxy with an integrated magnitude of 10.3, located southeast of β Arietis and 15 arcminutes west of 15 Arietis. It is a relatively bright galaxy and shows obvious nebulosity and ellipticity in an amateur telescope. It is 7.2 by 4.2 arcminutes, meaning that its surface brightness, magnitude 13.6, is significantly lower than its integrated magnitude. NGC 772 is a class SA(s)b galaxy, which means that it is an unbarred spiral galaxy without a ring that possesses a somewhat prominent bulge and spiral arms that are wound somewhat tightly. The main arm, on the northwest side of the galaxy, is home to many star forming regions; this is due to previous gravitational interactions with other galaxies. NGC 772 has a small companion galaxy, NGC 770, that is about 113,000 light-years away from the larger galaxy. The two galaxies together are also classified as Arp 78 in the Arp peculiar galaxy catalog. NGC 772 has a diameter of 240,000 light-years and the system is 114 million light-years from Earth. Another spiral galaxy in Aries is NGC 673, a face-on class SAB(s)c galaxy. It is a weakly barred spiral galaxy with loosely wound arms. It has no ring and a faint bulge and is 2.5 by 1.9 arcminutes. It has two primary arms with fragments located farther from the core. 171,000 light-years in diameter, NGC 673 is 235 million light-years from Earth.

text: NGC 772

text: is a

text: spiral galaxy

text: with an

text: integrated magnitude

text: of 10.3, located southeast of β Arietis and 15 arcminutes west of

text: 15 Arietis

text: . It is a relatively bright galaxy and shows obvious nebulosity and ellipticity in an amateur telescope. It is 7.2 by 4.2 arcminutes, meaning that its

text: surface brightness

text: , magnitude 13.6, is significantly lower than its integrated magnitude. NGC 772 is a

text: class SA(s)b galaxy

text: , which means that it is an unbarred spiral galaxy without a ring that possesses a somewhat prominent

text: bulge

text: and spiral arms that are wound somewhat tightly. The main arm, on the northwest side of the galaxy, is home to many

text: star forming regions

text: ; this is due to previous

text: gravitational interactions

text: with other galaxies. NGC 772 has a small companion galaxy,

text: NGC 770

text: , that is about 113,000 light-years away from the larger galaxy. The two galaxies together are also classified as Arp 78 in the

text: Arp peculiar galaxy catalog

text: . NGC 772 has a diameter of 240,000 light-years and the system is 114 million light-years from Earth. Another spiral galaxy in Aries is

text: NGC 673

text: , a face-on class SAB(s)c galaxy. It is a weakly

text: barred spiral galaxy

text: with loosely wound arms. It has no ring and a faint bulge and is 2.5 by 1.9 arcminutes. It has two primary arms with fragments located farther from the core. 171,000 light-years in diameter, NGC 673 is 235 million light-years from Earth.

text: The stars within an asterism rarely have any substantial astrophysical relationship to each other, and their apparent proximity when viewed from Earth disguises the fact that they are far apart, some being much farther from Earth than others. However, there are some exceptions: almost all of the stars in the constellation of Ursa Major (including most of the Big Dipper) are genuinely close to one another, travel through the galaxy with similar velocities, and are likely to have formed together as part of a cluster that is slowly dispersing. These stars form the Ursa Major moving group.

text: The stars within an asterism rarely have any substantial astrophysical relationship to each other, and their apparent proximity when viewed from Earth disguises the fact that they are far apart, some being much farther from Earth than others. However, there are some exceptions: almost all of the stars in the constellation of Ursa Major (including most of the Big Dipper) are genuinely close to one another, travel through the galaxy with similar

text: velocities

text: , and are likely to have formed together as part of a

text: cluster

text: that is slowly dispersing. These stars form the

text: Ursa Major moving group

text: The Northern Local Supervoid is a region of space devoid of rich clusters of galaxies, known as a void. It is the closest supervoid and is located between the Virgo (Local), Coma and Hercules superclusters. On the sky, it is located between Boötes, Virgo, and Serpens Caput constellations. It contains a few small galaxies (primarily spirals) and galaxy clusters, but is mostly empty. The faint galaxies within this void divide the region into smaller voids, which are 3–10 times smaller than the supervoid. The center is located  away at approximately (, ) and it is  in diameter across its narrowest width.

text: The Northern Local Supervoid is a region of space devoid of rich clusters of

text: galaxies

text: , known as a

text: void

text: . It is the closest supervoid and is located between the

text: Virgo

text: (Local),

text: Coma

text: and

text: Hercules

text: supercluster

text: s. On the sky, it is located between

text: Boötes

text: Virgo

text: , and

text: Serpens Caput

text: constellation

text: s. It contains a few small

text: galaxies

text: (primarily

text: spirals

text: ) and galaxy clusters, but is mostly empty. The faint galaxies within this void divide the region into smaller voids, which are 3–10 times smaller than the supervoid. The center is located  away at approximately (, ) and it is  in diameter across its narrowest width.

text: Globular clusters, which are found in the halo of a galaxy, contain considerably more stars and are much older than the less dense galactic, or open clusters, which are found in the disk. Globular clusters are fairly common; there are about 150 to 158 currently known globular clusters in the Milky Way, with perhaps 10 to 20 more still undiscovered. These globular clusters orbit the Galaxy at radii of 40 kiloparsecs (130,000 light-years) or more. Larger galaxies can have more: Andromeda Galaxy, for instance, may have as many as 500. Some giant elliptical galaxies (particularly those at the centers of galaxy clusters) such as M87, have as many as 13,000 globular clusters.

text: Globular clusters, which are found in the

text: halo

text: of a

text: galaxy

text: , contain considerably more stars and are much older than the less dense

text: galactic, or open cluster

text: s, which are found in the disk. Globular clusters are fairly common; there are about 150 to 158 currently known globular clusters in the

text: Milky Way

text: , with perhaps 10 to 20 more still undiscovered. These globular clusters orbit the Galaxy at radii of 40

text: kiloparsecs

text: light-year

text: s) or more. Larger galaxies can have more:

text: Andromeda Galaxy

text: , for instance, may have as many as 500. Some giant

text: elliptical galaxies

text: (particularly those at the centers of

text: galaxy cluster

text: s) such as

text: , have as many as 13,000 globular clusters.

text: The Circinus Galaxy (ESO 97-G13) is a Seyfert galaxy in the Circinus constellation.  It is located 4 degrees below the Galactic plane, and, at a distance of 13 million light-years, it is one of the closest to the Milky Way.  The galaxy is undergoing tumultuous changes, as rings of gas are being ejected from the galaxy.  The outermost ring is 700 light-years from the center of the galaxy and the inner ring is 130 light-years out.  Although the Circinus galaxy  can be seen using a small telescope, it was not noticed until 1977 because it lies close to the plane of the Milky Way and is obscured by galactic dust.  The Circinus Galaxy is a Type II Seyfert galaxy and is one of the closest known active galaxies to the Milky Way, though it is probably slightly further away than Centaurus A.

text: The Circinus Galaxy (ESO 97-G13) is a

text: Seyfert galaxy

text: in the

text: Circinus constellation

text: .  It is located 4 degrees below the

text: Galactic plane

text: , and, at a distance of 13 million

text: light-year

text: s, it is one of the closest to the

text: Milky Way

text: .  The galaxy is undergoing tumultuous changes, as rings of gas are being ejected from the galaxy.  The outermost ring is 700 light-years from the center of the galaxy and the inner ring is 130 light-years out.  Although the Circinus galaxy  can be seen using a small telescope, it was not noticed until 1977 because it lies close to the plane of the Milky Way and is obscured by galactic dust.  The Circinus Galaxy is a Type II

text: Seyfert galaxy

text: and is one of the closest known

text: active galaxies

text: to the

text: Milky Way

text: , though it is probably slightly further away than

text: Centaurus A

text: Along the pathway are thirteen markers denoting the passage of each billion years. At eight landings, panels show visitors the relative size of the universe at that point in time, along with major developmental stages of the universe including the first generation of stars, globular clusters, quasars, elliptical galaxies, galactic bulges, radio galaxies, the Milky Way Galaxy, galactic disks, and later generations of stars. At each of the landings, computer interactives provide overviews of the entire pathway, and more in-depth information, as well as connections to exhibit topics in the Hall of the Universe.

text: Along the pathway are thirteen markers denoting the passage of each billion years. At eight landings, panels show visitors the relative size of the universe at that point in time, along with major developmental stages of the universe including the first generation of stars,

text: globular clusters

text: quasar

text: s,

text: elliptical galaxies

text: galactic bulges

text: radio galaxies

text: , the

text: Milky Way Galaxy

text: galactic disk

text: s, and later generations of stars. At each of the landings, computer interactives provide overviews of the entire pathway, and more in-depth information, as well as connections to exhibit topics in the Hall of the Universe.

text: Examples of chaotic rotation include Hyperion, a moon of Saturn which rotates so unpredictably that the Cassini probe could not be reliably scheduled to pass by unexplored regions, and Pluto's Nix, Hydra, and possibly Styx and Kerberos. According to Mark R. Snowalter, author of a recent study, "Nix can flip its entire pole. It could actually be possible to spend a day on Nix in which the sun rises in the east and sets in the north. It is almost random-looking in the way it rotates." Another example is that of galaxies; from careful observation by the Keck and Hubble Telescopes of hundreds of galaxies, a trend was discovered that suggests galaxies such as our own Milky Way used to have a very chaotic rotation, with planetary bodies and stars rotating randomly. New evidence suggests that our galaxy and other have settled into an orderly, disk-like rotation over the past 8 million years and that other galaxies are slowly following suit over time.

text: Examples of chaotic rotation include

text: Hyperion

text: , a moon of

text: Saturn

text: which rotates so unpredictably that the

text: Cassini probe

text: could not be reliably scheduled to pass by unexplored regions, and

text: Pluto's

text: Nix

text: Hydra

text: , and possibly

text: Styx

text: and

text: Kerberos

text: . According to Mark R. Snowalter, author of a recent study, "Nix can flip its entire pole. It could actually be possible to spend a day on Nix in which the sun rises in the east and sets in the north. It is almost random-looking in the way it rotates." Another example is that of

text: galaxies

text: ; from careful observation by the

text: Keck

text: and

text: Hubble Telescopes

text: of hundreds of galaxies, a trend was discovered that suggests galaxies such as our own

text: Milky Way

text: used to have a very chaotic rotation, with

text: planetary bodies

text: and stars rotating randomly. New evidence suggests that our galaxy and other have settled into an orderly, disk-like rotation over the past 8 million years and that other galaxies are slowly following suit over time.

text: Tololo-1247-232 (Tol 1247 or T1247)) is a small galaxy at a distance of  (redshift z=0.0480). It is situated in the southern equatorial constellation of Hydra. Visually Tol 1247 appears to be an irregular or possibly a barred spiral galaxy. Tol 1247 is named after the surveys that were carried at the Cerro Tololo Inter-American Observatory (CTIO), the first of which was in 1976. It is one of nine galaxies in the local universe known to emit Lyman Continuum photons (LyC).

text: Tololo-1247-232 (Tol 1247 or T1247)) is a small

text: galaxy

text: at a distance of  (

text: redshift

text: z=0.0480). It is situated in the southern equatorial constellation of

text: Hydra

text: . Visually Tol 1247 appears to be an irregular or possibly a barred spiral galaxy. Tol 1247 is named after the surveys that were carried at the

text: Cerro Tololo Inter-American Observatory

text: (CTIO), the first of which was in 1976. It is one of nine galaxies in the local universe known to emit

text: Lyman Continuum photons

text: (LyC).

text: Elliptical galaxies are preferentially found in galaxy clusters and in compact groups of galaxies.

text: Elliptical galaxies are preferentially found in

text: galaxy clusters

text: and in compact

text: groups of galaxies

text: The prominent open cluster the Pleiades has been recognized as a group of stars since antiquity, while the Hyades forms part of Taurus, one of the oldest constellations. Other open clusters were noted by early astronomers as unresolved fuzzy patches of light. The Roman astronomer Ptolemy mentions the Praesepe, the Double Cluster in Perseus, and the Ptolemy Cluster, while the Persian astronomer Al-Sufi wrote of the Omicron Velorum cluster. However, it would require the invention of the telescope to resolve these nebulae into their constituent stars. Indeed, in 1603 Johann Bayer gave three of these clusters designations as if they were single stars.

text: The prominent open cluster the Pleiades has been recognized as a group of stars since antiquity, while the Hyades forms part of

text: Taurus

text: , one of the oldest constellations. Other open clusters were noted by early astronomers as unresolved fuzzy patches of light. The Roman astronomer

text: Ptolemy

text: mentions the

text: Praesepe

text: , the

text: Double Cluster

text: in

text: Perseus

text: , and the

text: Ptolemy Cluster

text: , while the Persian astronomer

text: Al-Sufi

text: wrote of the

text: Omicron Velorum cluster

text: . However, it would require the invention of the

text: telescope

text: to resolve these nebulae into their constituent stars. Indeed, in 1603

text: Johann Bayer

text: gave three of these clusters

text: designations

text: as if they were single stars.

text: These two populations have been observed in many galaxies, especially massive elliptical galaxies. Both groups are nearly as old as the universe itself and are of similar ages, but differ in their metal abundances. Many scenarios have been suggested to explain these subpopulations, including violent gas-rich galaxy mergers, the accretion of dwarf galaxies, and multiple phases of star formation in a single galaxy. In the Milky Way, the metal-poor clusters are associated with the halo and the metal-rich clusters with the bulge.

text: These two populations have been observed in many galaxies, especially massive

text: elliptical galaxies

text: . Both groups are nearly as old as the universe itself and are of similar ages, but differ in their metal abundances. Many scenarios have been suggested to explain these subpopulations, including violent gas-rich galaxy mergers, the accretion of dwarf galaxies, and multiple phases of star formation in a single galaxy. In the

text: Milky Way

text: , the metal-poor clusters are associated with the halo and the metal-rich clusters with the bulge.

text: The municipalities of Liechtenstein, the Gemeinden, exhibit complex shapes, despite their small size.

text: H II regions can be seen to considerable distances in the universe, and the study of extragalactic H II regions is important in determining the distance and chemical composition of galaxies. Spiral and irregular galaxies contain many H II regions, while elliptical galaxies are almost devoid of them. In spiral galaxies, including our Milky Way, H II regions are concentrated in the spiral arms, while in irregular galaxies they are distributed chaotically. Some galaxies contain huge H II regions, which may contain tens of thousands of stars. Examples include the 30 Doradus region in the Large Magellanic Cloud and NGC 604 in the Triangulum Galaxy.

text: H II regions can be seen to considerable distances in the universe, and the study of extragalactic H II regions is important in determining the distance and chemical composition of

text: galaxies

text: Spiral

text: and

text: irregular

text: galaxies contain many H II regions, while

text: elliptical

text: galaxies are almost devoid of them. In spiral galaxies, including our

text: Milky Way

text: , H II regions are concentrated in the

text: spiral arm

text: s, while in irregular galaxies they are distributed chaotically. Some galaxies contain huge H II regions, which may contain tens of thousands of stars. Examples include the

text: 30 Doradus

text: region in the

text: Large Magellanic Cloud

text: and

text: NGC 604

text: in the

text: Triangulum Galaxy

text: In astronomy, it is widely accepted that most stars are born within molecular clouds known as stellar nurseries. The stars formed within such a cloud compose open clusters containing dozens to thousands of members. These clusters dissociate over time. Stars that separate themselves from the cluster's core are designated as members of the cluster's stellar association. If the remnant later drifts through the Milky Way as a coherent assemblage, then it is termed a moving group.

text: In

text: astronomy

text: , it is widely accepted that most stars are born within molecular clouds known as

text: stellar nurseries

text: . The stars formed within such a cloud compose

text: open cluster

text: s containing dozens to thousands of members. These clusters dissociate over time. Stars that separate themselves from the cluster's core are designated as members of the cluster's stellar association. If the remnant later drifts through the Milky Way as a coherent assemblage, then it is termed a moving group.

text: Studies from RAVE either concentrate on peculiar stars and objects or overall trends for the different components of our Galaxy, with a main focus of the structure and formation of the Milky Way. For example, RAVE is suited to searching for stellar streams, some of which are remnants of dwarf galaxies that merged with the Milky Way during galaxy formation. A search for a stellar stream from the Sagittarius Dwarf Elliptical Galaxy - which is currently merging with the Milky Way - in the vicinity of the sun yielded a null result, which helps constrain the shape of the Milky Way's dark halo. Another study of the highest velocity stars was used to constrain the local Galactic escape velocity and so the mass of the dark halo.

text: Studies from RAVE either concentrate on peculiar stars and objects or overall trends for the different components of our Galaxy, with a main focus of the structure and formation of the Milky Way. For example, RAVE is suited to searching for

text: stellar streams

text: , some of which are remnants of

text: dwarf galaxies

text: that merged with the Milky Way during

text: galaxy formation

text: . A search for a stellar stream from the

text: Sagittarius Dwarf Elliptical Galaxy

text: - which is currently merging with the Milky Way - in the vicinity of the sun yielded a

text: null result

text: , which helps constrain the shape of the Milky Way's

text: dark halo

text: . Another study of the highest velocity stars was used to constrain the local Galactic

text: escape velocity

text: and so the

text: mass

text: of the dark halo.

text: The Hubble Space Telescope has been used to provide convincing observational evidence of this stellar mass-sorting process in globular clusters. Heavier stars slow down and crowd at the cluster's core, while lighter stars pick up speed and tend to spend more time at the cluster's periphery. The globular star cluster 47 Tucanae, which is made up of about 1 million stars, is one of the densest globular clusters in the Southern Hemisphere. This cluster was subjected to an intensive photographic survey, which allowed astronomers to track the motion of its stars. Precise velocities were obtained for nearly 15,000 stars in this cluster.

text: The Hubble Space Telescope has been used to provide convincing observational evidence of this stellar mass-sorting process in globular clusters. Heavier stars slow down and crowd at the cluster's core, while lighter stars pick up speed and tend to spend more time at the cluster's periphery. The globular star cluster

text: 47 Tucanae

text: , which is made up of about 1 million stars, is one of the densest globular clusters in the Southern Hemisphere. This cluster was subjected to an intensive photographic survey, which allowed astronomers to track the motion of its stars. Precise velocities were obtained for nearly 15,000 stars in this cluster.

text: An intermediate spiral galaxy is a galaxy that is in between the classifications of a barred spiral galaxy and an unbarred spiral galaxy. It is designated as SAB in the galaxy morphological classification scheme. By definition, a galaxy is a congregation of stars held together by gravity. The first intermediate spiral galaxy discovered is the Milky Way, by Galileo, in 1610. He was the first person with a telescope powerful enough to make such a discovery. Before Galileo, it was thought that all bright objects in the sky were either the planets in the Solar System, moons, comets, or stars. Until the beginning on the twentieth century, astronomers did not know the size of the Universe, but speculated it to be about as big as the Milky Way. In 1920, at the National Academy of Science, there was a big debate between Harlow Shapley and Heber D. Curtis on whether nebulae are small globular clusters surrounding the Milky Way, or separate galaxies located farther away. Nothing was resolved at the debate; neither side was able to provide conclusive evidence to prove their side correct over their opponent. In 1923, Edwin Hubble resolved the matter with a photograph that he took of the Andromeda Galaxy. What he found in his photograph was a very bright light source pulsing at a certain rate, a Cepheid variable, located outside the Milky Way. This can be used to determine the distance to it. Hubble proved that the Universe was full of galaxies, and disproved that the Milky Way was the extent of the Universe. There are many types of galaxies in the Universe, elliptical, barred spiral galaxies; they vary in shape and size, but on average spiral galaxies are the most abundant.

text: An intermediate spiral galaxy is a galaxy that is in between the classifications of a

text: barred spiral galaxy

text: and an

text: unbarred spiral galaxy

text: . It is designated as SAB in the

text: galaxy morphological classification

text: He specializes in the study of star clusters and galaxies.

text: He specializes in the study of

text: star clusters

text: and

text: galaxies

text: De Vaucouleurs also assigned numerical values to each class of galaxy in his scheme. Values of the numerical Hubble stage T run from −6 to +10, with negative numbers corresponding to early-type galaxies (ellipticals and lenticulars) and positive numbers to late types (spirals and irregulars). Elliptical galaxies are divided into three 'stages': compact ellipticals (cE), normal ellipticals (E) and late types (E). Lenticulars are similarly subdivided into early (S), intermediate (S) and late (S) types. Irregular galaxies can be of type magellanic irregulars (T = 10) or 'compact' (T = 11).

text: Throughout most of the 1960s when Pontiac annually captured third place in industry sales, behind Chevrolet and Ford, the Catalina was also often the industry's third best-selling full-sized car behind the first-place Chevrolet Impala and second-place Ford Galaxie 500. The Catalina's success in the low-medium priced field led many competitors to respond with similar products such as the 1961 Chrysler Newport, a less-expensive Chrysler that was priced lower than base models bearing the Chrysler nameplate in recent previous years; and the 1962 Dodge Custom 880 and 1963 Mercury Monterey, both of which were introduced as full-fledged low-medium priced full-sized cars in size and power that followed unsuccessful efforts by Mercury and Dodge to bring out downsized full-sized cars.

text: Throughout most of the 1960s when Pontiac annually captured third place in industry sales, behind Chevrolet and Ford, the Catalina was also often the industry's third best-selling full-sized car behind the first-place

text: Chevrolet Impala

text: and second-place

text: Ford Galaxie 500

text: . The Catalina's success in the low-medium priced field led many competitors to respond with similar products such as the 1961

text: Chrysler Newport

text: , a less-expensive Chrysler that was priced lower than base models bearing the Chrysler nameplate in recent previous years; and the 1962

text: Dodge Custom 880

text: and 1963

text: Mercury Monterey

text: , both of which were introduced as full-fledged low-medium priced full-sized cars in size and power that followed unsuccessful efforts by Mercury and Dodge to bring out downsized full-sized cars.

text: Different types of galaxies have different histories of star formation and hence planet formation. Planet formation is affected by the ages, metallicities, and orbits of stellar populations within a galaxy. Distribution of stellar populations within a galaxy varies between the different types of galaxies.Stars in elliptical galaxies are much older than stars in spiral galaxies. Most elliptical galaxies contain mainly low-mass stars, with minimal star-formation activity. The distribution of the different types of galaxies in the universe depends on their location within galaxy clusters, with elliptical galaxies found mostly close to their centers.

text: Different

text: types of galaxies

text: have different histories of

text: star formation

text: and hence

text: planet formation

text: . Planet formation is affected by the ages, metallicities, and orbits of stellar populations within a galaxy. Distribution of stellar populations within a galaxy varies between the different types of galaxies.Stars in

text: elliptical galaxies

text: are much older than stars in

text: spiral galaxies

text: . Most elliptical galaxies contain mainly

text: low-mass stars

text: , with minimal

text: star-formation

text: activity. The distribution of the different types of galaxies in the

text: universe

text: depends on their location within

text: galaxy cluster

text: s, with elliptical galaxies found mostly close to their centers.

text: The Tucana Dwarf galaxy is one of only two dwarf spheroidal galaxies in the Local Group  not located near the Milky Way or the Andromeda Galaxy. It is therefore likely to have evolved in isolation for most of its history.

text: The Tucana Dwarf galaxy is one of only two dwarf spheroidal galaxies in the Local Group  not located near the Milky Way or the

text: Andromeda Galaxy

text: . It is therefore likely to have evolved in isolation for most of its history.

text: As most galaxies of this type are present in rich galaxy clusters, it has been proposed that this may be one of the reasons that converts normal spirals into anemic ones. Studies of spiral galaxies in the nearby Virgo cluster have shown not only how, unlike in isolated spiral galaxies, in most cases their neutral gas and star formation are truncated within their optical disks, in some cases quite severely, but also how star formation activity in them is lower than on spirals outside clusters,: this means that processes that take place in galaxy clusters as interactions with the intracluster medium like ram-pressure stripping and/or interactions with other neighboring galaxies are responsible of the origin of anemic galaxies, stripping the normal spirals of their gas, increasing in some cases their star formation activity, and thus in the end quenching the latter as their gas is exhausted and not replenished. Spiral galaxies may have become anemic ones by exhausting their supply of gas via star formation activity.

text: As most galaxies of this type are present in rich

text: galaxy cluster

text: s, it has been proposed that this may be one of the reasons that converts normal spirals into anemic ones. Studies of spiral galaxies in the nearby

text: Virgo cluster

text: have shown not only how, unlike in isolated spiral galaxies, in most cases their neutral gas and star formation are truncated within their optical disks, in some cases quite severely, but also how star formation activity in them is lower than on spirals outside clusters,: this means that processes that take place in galaxy clusters as interactions with the

text: intracluster medium

text: like

text: ram-pressure stripping

text: and/or

text: interactions with other neighboring galaxies

text: are responsible of the origin of anemic galaxies, stripping the normal spirals of their gas, increasing in some cases their star formation activity, and thus in the end quenching the latter as their gas is exhausted and not replenished. Spiral galaxies may have become anemic ones by exhausting their supply of gas via star formation activity.

text: Studies say that a triple-star system was traveling through the center of the Milky Way when it came too close to the galactic center (which is thought to have a giant black hole). One of the stars was captured by the black hole causing the other two to be ejected from the Milky Way, where they merged to form a hot blue star. The star is moving at a speed of , about three times faster than the Sun's orbital velocity around the galaxy's center, and also faster than the galaxy's escape velocity.

text: Studies say that a triple-star system was traveling through the center of the

text: Milky Way

text: when it came too close to the galactic center (which is thought to have a giant

text: black hole

text: ). One of the stars was captured by the black hole causing the other two to be ejected from the

text: Milky Way

text: , where they merged to form a hot blue star. The star is moving at a speed of , about three times faster than the

text: Sun

text: 's orbital velocity around the

text: galaxy

text: 's center, and also faster than the galaxy's

text: escape velocity

text: Astronomers have estimated the Milky Way galaxy, will collide with the Andromeda galaxy in about 4.5 billion years. It is thought that the two spiral galaxies will eventually merge to become an elliptical galaxy or perhaps a large disk galaxy.

text: Astronomers have estimated the

text: Milky Way galaxy

text: , will collide with the

text: Andromeda galaxy

text: in about 4.5 billion years. It is thought that the two

text: spiral galaxies

text: will eventually merge to become an

text: elliptical galaxy

text: or perhaps a large

text: disk galaxy

text: Various morphological features of galaxies can affect their potential for habitability. Spiral arms, for example, are the location of star formation, but they contain numerous giant molecular clouds and a high density of stars that can perturb a star's Oort cloud, sending avalanches of comets and asteroids toward any planets further in. In addition, the high density of stars and rate of massive star formation can expose any stars orbiting within the spiral arms for too long to supernova explosions, reducing their prospects for the survival and development of life. Considering these factors, the Sun is advantageously placed within the galaxy because, in addition to being outside a spiral arm, it orbits near the corotation radius, maximizing the interval between spiral-arm crossings.

text: Various morphological features of galaxies can affect their potential for habitability. Spiral arms, for example, are the location of star formation, but they contain numerous giant molecular clouds and a high density of stars that can perturb a star's

text: Oort cloud

text: , sending avalanches of comets and asteroids toward any planets further in. In addition, the high density of stars and rate of massive star formation can expose any stars orbiting within the spiral arms for too long to supernova explosions, reducing their prospects for the survival and development of life. Considering these factors, the

text: Sun

text: is advantageously placed within the galaxy because, in addition to being outside a spiral arm, it orbits near the

text: corotation radius

text: , maximizing the interval between spiral-arm crossings.

text: These new-found star clusters contain hundreds of thousands of stars, a similar number of stars that can be found in globular clusters. The clusters also share other characteristics with globular clusters, e.g. the stellar populations and metallicity. What distinguishes them from the globular clusters is that they are much larger – several hundred light-years across – and hundreds of times less dense. The distances between the stars are, therefore, much greater within the newly discovered extended clusters. Parametrically, these clusters lie somewhere between a (low dark matter) globular cluster and a (dark matter-dominated) dwarf spheroidal galaxy.

text: These new-found star clusters contain hundreds of thousands of stars, a similar number of stars that can be found in globular clusters. The clusters also share other characteristics with globular clusters, e.g. the stellar populations and metallicity. What distinguishes them from the globular clusters is that they are much larger – several hundred light-years across – and hundreds of times less dense. The distances between the stars are, therefore, much greater within the newly discovered extended clusters. Parametrically, these clusters lie somewhere between a (low dark matter) globular cluster and a (dark matter-dominated)

text: dwarf spheroidal galaxy

text: It has been speculated that Omega Centauri may be the core of a dwarf galaxy that was disrupted and absorbed by the Milky Way. Indeed, Kapteyn's Star, which is currently only 13 light years away, is thought to originate from Omega Centauri. Omega Centauri's chemistry and motion in the Milky Way are also consistent with this picture. Like Mayall II, Omega Centauri has a range of metallicities and stellar ages that suggests that it did not all form at once (as globular clusters are thought to form) and may in fact be the remainder of the core of a smaller galaxy long since incorporated into the Milky Way.

text: It has been speculated that Omega Centauri may be the core of a

text: dwarf galaxy

text: that was disrupted and absorbed by the Milky Way. Indeed,

text: Kapteyn's Star

text: , which is currently only 13 light years away, is thought to originate from Omega Centauri. Omega Centauri's chemistry and motion in the Milky Way are also consistent with this picture. Like Mayall II, Omega Centauri has a range of

text: metallicities

text: and stellar ages that suggests that it did not all form at once (as globular clusters are thought to form) and may in fact be the remainder of the core of a smaller galaxy long since incorporated into the Milky Way.

text: The table below lists galaxies that have been consistently identified as group members in the Nearby Galaxies Catalog, the survey of Fouque et al., the Lyons Groups of Galaxies (LGG) Catalog, and the three group lists created from the Nearby Optical Galaxy sample of Giuricin et al.

text: It was realised as early as 1767 that the stars in a cluster were physically related, when the English naturalist Reverend John Michell calculated that the probability of even just one group of stars like the Pleiades being the result of a chance alignment as seen from Earth was just 1 in 496,000. Between 1774–1781, French astronomer Charles Messier published a catalogue of celestial objects that had a nebulous appearance similar to comets. This catalogue included 26 open clusters. In the 1790s, English astronomer William Herschel began an extensive study of nebulous celestial objects. He discovered that many of these features could be resolved into groupings of individual stars. Herschel conceived the idea that stars were initially scattered across space, but later became clustered together as star systems because of gravitational attraction. He divided the nebulae into eight classes, with classes VI through VIII being used to classify clusters of stars.

text: It was realised as early as 1767 that the stars in a cluster were physically related, when the English naturalist Reverend

text: John Michell

text: calculated that the probability of even just one group of stars like the Pleiades being the result of a chance alignment as seen from Earth was just 1 in 496,000. Between 1774–1781, French astronomer

text: Charles Messier

text: published a catalogue of celestial objects that had a nebulous appearance similar to

text: comet

text: s. This catalogue included 26 open clusters. In the 1790s, English astronomer

text: William Herschel

text: began an extensive study of nebulous celestial objects. He discovered that many of these features could be resolved into groupings of individual stars. Herschel conceived the idea that stars were initially scattered across space, but later became clustered together as star systems because of gravitational attraction. He divided the nebulae into eight classes, with classes VI through VIII being used to classify clusters of stars.

text: The Ori order their followers to begin constructing a fleet of ships after learning of the existence of the Milky Way galaxy in . Due to their advanced technology, their ships pose a considerable threat.

text: The

text: Ori

text: order their followers to begin constructing a fleet of ships after learning of the existence of the Milky Way galaxy in . Due to their advanced technology, their ships pose a considerable threat.

text: In 2004, a team of astronomers focused on the cluster to estimate the age of the Milky Way Galaxy. The team consisted of Luca Pasquini, Piercarlo Bonifacio, Sofia Randich, Daniele Galli, and Raffaele G. Gratton. They used the UV-Visual Echelle Spectrograph of the Very Large Telescope at Cerro Paranal to measure the beryllium content of two stars in the cluster. This allowed them to deduce the time elapsed between the rise of the first generation of stars in the entire Galaxy and the first generation of stars in the cluster. This, added to the estimated age of the stars in the cluster, gives an estimate for the age for the Galaxy: about 13.6 billion years, which is nearly as old as the universe itself.

text: In 2004, a team of

text: astronomer

text: s focused on the cluster to estimate the age of the

text: Milky Way Galaxy

text: . The team consisted of Luca Pasquini, Piercarlo Bonifacio, Sofia Randich, Daniele Galli, and Raffaele G. Gratton. They used the UV-Visual

text: Echelle Spectrograph

text: of the

text: Very Large Telescope

text: at

text: Cerro Paranal

text: to measure the

text: beryllium

text: content of two stars in the cluster. This allowed them to deduce the time elapsed between the rise of the first generation of stars in the entire Galaxy and the first generation of stars in the cluster. This, added to the estimated age of the stars in the cluster, gives an estimate for the age for the Galaxy: about 13.6

text: billion

text: years, which is nearly as

text: old as the universe

text: itself.

text: Because most if not all stars form clustered, star clusters are to be viewed the fundamental building blocks of galaxies. The violent gas-expulsion events that shape and destroy many star clusters at birth leave their imprint in the morphological and kinematical structures of galaxies. Most open clusters form with at least 100 stars and a mass of 50 or more solar masses. The largest clusters can have 10 solar masses, with the massive cluster Westerlund 1 being estimated at 5 × 10 solar masses; close to that of a globular cluster. While open clusters and globular clusters form two fairly distinct groups, there may not be a great deal of difference in appearance between a very sparse globular cluster and a very rich open cluster. Some astronomers believe the two types of star clusters form via the same basic mechanism, with the difference being that the conditions that allowed the formation of the very rich globular clusters containing hundreds of thousands of stars no longer prevail in the Milky Way.

text: Because most if not all stars form clustered,

text: star cluster

text: s are to be viewed the fundamental building blocks of galaxies. The violent gas-expulsion events that shape and destroy many star clusters at birth leave their imprint in the morphological and kinematical structures of galaxies. Most open clusters form with at least 100 stars and a mass of 50 or more

text: solar mass

text: es. The largest clusters can have 10 solar masses, with the massive cluster

text: Westerlund 1

text: being estimated at 5 × 10 solar masses; close to that of a globular cluster. While open clusters and globular clusters form two fairly distinct groups, there may not be a great deal of difference in appearance between a very sparse globular cluster and a very rich open cluster. Some astronomers believe the two types of star clusters form via the same basic mechanism, with the difference being that the conditions that allowed the formation of the very rich globular clusters containing hundreds of thousands of stars no longer prevail in the Milky Way.

text: IC 10 is an irregular galaxy that is the only known starburst galaxy in the Local Group of galaxies.

text: IC 10

text: is an irregular galaxy that is the only known

text: starburst galaxy

text: in the Local Group of galaxies.

text: Water megamasers were the first type of megamaser discovered. The first water megamaser was found in 1979 in NGC 4945, a galaxy in the nearby Centaurus A/M83 Group. The first hydroxyl megamaser was found in 1982 in Arp 220, which is the nearest ultraluminous infrared galaxy to the Milky Way. All subsequent OH megamasers that have been discovered are also in luminous infrared galaxies, and there are a small number of OH kilomasers hosted in galaxies with lower infrared luminosities. Most luminous infrared galaxies have recently merged or interacted with another galaxy, and are undergoing a burst of star formation. Many of the characteristics of the emission in hydroxyl megamasers are distinct from that of hydroxyl masers within the Milky Way, including the amplification of background radiation and the ratio of hydroxyl lines at different frequencies. The population inversion in hydroxyl molecules is produced by far infrared radiation that results from absorption and re-emission of light from forming stars by surrounding interstellar dust. Zeeman splitting of hydroxyl megamaser lines may be used to measure magnetic fields in the masing regions, and this application represents the first detection of Zeeman splitting in a galaxy other than the Milky Way.

text: Water megamasers were the first type of megamaser discovered. The first water megamaser was found in 1979 in

text: NGC 4945

text: , a galaxy in the nearby

text: Centaurus A/M83 Group

text: . The first hydroxyl megamaser was found in 1982 in

text: Arp 220

text: , which is the nearest

text: ultraluminous infrared galaxy

text: to the Milky Way. All subsequent OH megamasers that have been discovered are also in luminous infrared galaxies, and there are a small number of OH kilomasers hosted in galaxies with lower infrared luminosities. Most luminous infrared galaxies have recently merged or interacted with another galaxy, and are undergoing a burst of

text: star formation

text: . Many of the characteristics of the emission in hydroxyl megamasers are distinct from that of hydroxyl masers within the

text: Milky Way

text: , including the amplification of background radiation and the ratio of hydroxyl lines at different frequencies. The

text: population inversion

text: in hydroxyl molecules is produced by far infrared radiation that results from absorption and re-emission of light from forming stars by surrounding

text: interstellar dust

text: Zeeman splitting

text: of hydroxyl megamaser lines may be used to measure

text: magnetic field

text: s in the masing regions, and this application represents the first detection of Zeeman splitting in a galaxy other than the Milky Way.

text: In 2012, a microquasar, a radio burst emanating from a smaller black hole, was detected in the Andromeda Galaxy. The progenitor black hole is located near the galactic center and has about 10 . Discovered through a data collected by the European Space Agency's XMM-Newton probe, and subsequently observed by NASA's Swift Gamma-Ray Burst Mission and Chandra X-Ray Observatory, the Very Large Array, and the Very Long Baseline Array, the microquasar was the first observed within the Andromeda Galaxy and the first outside of the Milky Way Galaxy.

text: In 2012, a

text: microquasar

text: , a radio burst emanating from a smaller black hole, was detected in the Andromeda Galaxy. The progenitor black hole is located near the galactic center and has about 10

text: . Discovered through a data collected by the

text: European Space Agency

text: 's

text: XMM-Newton

text: probe, and subsequently observed by

text: NASA

text: 's

text: Swift Gamma-Ray Burst Mission

text: and

text: Chandra X-Ray Observatory

text: , the

text: Very Large Array

text: , and the

text: Very Long Baseline Array

text: , the microquasar was the first observed within the Andromeda Galaxy and the first outside of the Milky Way Galaxy.

text: Galaxies undergoing such rapid star formation are known as starburst galaxies. The post-merger elliptical galaxy has a very low gas content, and so H II regions can no longer form. Twenty-first century observations have shown that a very small number of H II regions exist outside galaxies altogether. These intergalactic H II regions may be the remnants of tidal disruptions of small galaxies, and in some cases may represent a new generation of stars in a galaxy's most recently accreted gas.

text: Galaxies undergoing such rapid star formation are known as

text: starburst galaxies

text: . The post-merger elliptical galaxy has a very low gas content, and so H II regions can no longer form. Twenty-first century observations have shown that a very small number of H II regions exist outside galaxies altogether. These intergalactic H II regions may be the remnants of tidal disruptions of small galaxies, and in some cases may represent a new generation of stars in a galaxy's most recently accreted gas.

text: DDO 74 (also known as Leo I, Regulus Dwarf, PGC 29488 or UGC 5470) lies approximately 820,000 light years away in the constellation Leo. It is one of the most distant satellite galaxy of our Milky Way. The dwarf spheroidal galaxy is located only 12 arcminutes from Regulus (α Leonis), and the light from Regulus makes the visibility of DDO 74 becomes poor, so it is difficult to be observed.

text: DDO 74

text: (also known as

text: Leo

text: I,

text: Regulus

text: Dwarf

text: PGC

text: 29488 or

text: UGC

text: 5470) lies approximately 820,000

text: light years

text: away in the

text: constellation

text: Leo

text: . It is one of the most distant

text: satellite galaxy

text: of our

text: Milky Way

text: . The

text: dwarf spheroidal galaxy

text: is located only 12 arcminutes from

text: Regulus

text: α Leonis

text: ), and the light from

text: Regulus

text: makes the

text: visibility

text: of

text: DDO 74

text: becomes poor, so it is difficult to be observed.

text: 2. Weak lensing: where the distortions of background sources are much smaller and can only be detected by analyzing large numbers of sources in a statistical way to find coherent distortions of only a few percent. The lensing shows up statistically as a preferred stretching of the background objects perpendicular to the direction to the center of the lens.By measuring the shapes and orientations of large numbers of distant galaxies, their orientations can be averaged to measure the shear of the lensing field in any region. This, in turn, can be used to reconstruct the mass distribution in the area: in particular, the background distribution of dark matter can be reconstructed. Since galaxies are intrinsically elliptical and the weak gravitational lensing signal is small, a very large number of galaxies must be used in these surveys. These weak lensing surveys must carefully avoid a number of important sources of systematic error: the intrinsic shape of galaxies, the tendency of a camera's point spread function to distort the shape of a galaxy and the tendency of atmospheric seeing to distort images must be understood and carefully accounted for. The results of these surveys are important for cosmological parameter estimation, to better understand and improve upon the Lambda-CDM model, and to provide a consistency check on other cosmological observations. They may also provide an important future constraint on dark energy.

text: Weak lensing

text: : where the distortions of background sources are much smaller and can only be detected by analyzing large numbers of sources in a statistical way to find coherent distortions of only a few percent. The lensing shows up statistically as a preferred stretching of the background objects perpendicular to the direction to the center of the lens.By measuring the shapes and orientations of large numbers of distant galaxies, their orientations can be averaged to measure the

text: shear

text: of the lensing field in any region. This, in turn, can be used to reconstruct the mass distribution in the area: in particular, the background distribution of

text: dark matter

text: can be reconstructed. Since galaxies are intrinsically elliptical and the weak gravitational lensing signal is small, a very large number of galaxies must be used in these surveys. These weak lensing surveys must carefully avoid a number of important sources of

text: systematic error

text: : the intrinsic shape of galaxies, the tendency of a camera's

text: point spread function

text: to distort the shape of a galaxy and the tendency of

text: atmospheric seeing

text: to distort images must be understood and carefully accounted for. The results of these surveys are important for cosmological parameter estimation, to better understand and improve upon the

text: Lambda-CDM model

text: , and to provide a consistency check on other cosmological observations. They may also provide an important future constraint on

text: dark energy

text: During the 1959 model year the Galaxie series was added to Ford’s full-size range and the Skyliner model was absorbed into that series. Although the 1959 Galaxie was designated as a separate series, Galaxies carried both “Fairlane 500” and “Galaxie” badging, on the rear and sides respectively. It came with the standard 292CID 2-barrel 200 hp V8.

text: During the 1959 model year the

text: Galaxie

text: series was added to Ford’s full-size range and the Skyliner model was absorbed into that series. Although the 1959 Galaxie was designated as a separate series, Galaxies carried both “Fairlane 500” and “Galaxie” badging, on the rear and sides respectively. It came with the standard 292CID 2-barrel 200 hp V8.

text: A former colleague and academic rival of Washu from the Galaxy Academy, he is in service to Lady Tokimi in OVA 2 (in which he is the primary adversary) and is ordered by her to capture Washu and bring her to Tokimi. Clay uses the shape-shifting android Zero to replace Ryoko and capture Washu. However he is outsmarted by Washu, captured and handed over to the Galaxy Police.

text: A former colleague and academic rival of Washu from the Galaxy Academy, he is in service to Lady Tokimi in OVA 2 (in which he is the primary adversary) and is ordered by her to capture Washu and bring her to Tokimi. Clay uses the shape-shifting android

text: Zero

text: to replace Ryoko and capture Washu. However he is outsmarted by Washu, captured and handed over to the Galaxy Police.

text: The present enterprise, known as Galaxy Entertainment Inc. was established in 1999 by Ellis Jacob, a former Chief Operating Officer of Loews Cineplex Entertainment, and Stephen Brown, a former Cineplex Chief Financial Officer. With investments from Onex Corporation and Famous Players, the new company focused on smaller markets that were usually served by smaller theatres and old equipment, opening large, major chain-style locations under the Galaxy Cinemas banner.In October 2003, Loews Cineplex Entertainment, which was a merger of Cineplex Odeon and Sony's Loews Theatres in 1998, who went bankrupt in 2001 due to the economic recession of the early 2000s, consolidated its Canadian operations with Galaxy Cinemas, forming Cineplex Galaxy Income Fund. Jacob became the chief executive of Cineplex Galaxy Cinemas, and Brown became the CFO. Onex was the controlling shareholder of both Loews Cineplex Theatres and Galaxy Cinemas at the time of the merger, but sold its interest in Loews in June 2004. It maintained control of Cineplex Galaxy.

text: The present enterprise, known as Galaxy Entertainment Inc. was established in 1999 by Ellis Jacob, a former

text: Chief Operating Officer

text: of

text: Loews Cineplex Entertainment

text: , and Stephen Brown, a former Cineplex

text: Chief Financial Officer

text: . With investments from

text: Onex Corporation

text: and Famous Players, the new company focused on smaller markets that were usually served by smaller theatres and old equipment, opening large, major chain-style locations under the Galaxy Cinemas banner.In October 2003,

text: Loews Cineplex Entertainment

text: , which was a merger of Cineplex Odeon and

text: Sony

text: 's Loews Theatres in 1998, who went bankrupt in 2001 due to the economic recession of the early 2000s, consolidated its Canadian operations with Galaxy Cinemas, forming Cineplex Galaxy Income Fund. Jacob became the chief executive of Cineplex Galaxy Cinemas, and Brown became the CFO. Onex was the controlling shareholder of both Loews Cineplex Theatres and Galaxy Cinemas at the time of the merger, but sold its interest in Loews in June 2004. It maintained control of Cineplex Galaxy.

text: NGC 5544 is a barred spiral galaxy in the constellation Boötes. It is interacting with spiral galaxy NGC 5545.

text: NGC 5544 is a

text: barred spiral galaxy

text: in the constellation

text: Boötes

text: . It is interacting with spiral galaxy

text: NGC 5545

text: At the large end of the elliptical spectrum, there is further division, beyond Hubble classification. Beyond gE giant ellipticals, lies D-galaxies and cD-galaxies. These are similar to their smaller brethren, but more diffuse, with larger haloes. Some even appear more akin to lenticular galaxies.

text: At the large end of the elliptical spectrum, there is further division, beyond Hubble classification. Beyond gE giant ellipticals, lies

text: D-galaxies

text: and

text: cD-galaxies

text: . These are similar to their smaller brethren, but more diffuse, with larger haloes. Some even appear more akin to

text: lenticular galaxies

text: Spiral arms are regions of stars that extend from the center of spiral and barred spiral galaxies. These long, thin regions resemble a spiral and thus give spiral galaxies their name. Naturally, different classifications of spiral galaxies have distinct arm-structures. Sc and SBc galaxies, for instance, have very "loose" arms, whereas Sa and SBa galaxies have tightly wrapped arms (with reference to the Hubble sequence). Either way, spiral arms contain many young, blue stars (due to the high mass density and the high rate of star formation), which make the arms so bright.

text: Spiral arms are regions of

text: star

text: s that extend from the center of

text: spiral

text: and barred spiral

text: galaxies

text: . These long, thin regions resemble a spiral and thus give spiral galaxies their name. Naturally, different

text: classifications of spiral galaxies

text: have distinct arm-structures. Sc and SBc galaxies, for instance, have very "loose" arms, whereas Sa and SBa galaxies have tightly wrapped arms (with reference to the Hubble sequence). Either way, spiral arms contain many young, blue stars (due to the high mass density and the high rate of star formation), which make the arms so bright.

text: Because of their extreme masses they have relatively short lifespans and are mainly observed in young cosmic structures such as open clusters, the arms of spiral galaxies, and in irregular galaxies. They are rarely observed in spiral galaxy cores, elliptical galaxies, or globular clusters, most of which are believed to be composed of older stars, although the core of the Milky Way has recently been found to be home to several massive open clusters and associated young hot stars.

text: Because of their extreme masses they have relatively short lifespans and are mainly observed in young cosmic structures such as

text: open clusters

text: , the arms of

text: spiral galaxies

text: , and in

text: irregular galaxies

text: . They are rarely observed in spiral galaxy cores,

text: elliptical galaxies

text: , or

text: globular clusters

text: , most of which are believed to be composed of older stars, although the core of the Milky Way has recently been found to be home to several massive open clusters and associated young hot stars.

text: "Shape-note singers used tune books rather than hymnals. Hymnals were pocket-size books with texts only. Tune books were large oblong-shaped books with hard covers (nine inches by six inches was a typical size), often running to over four hundred pages. They included both music and text and were introduced by an extended essay on the rudiments of singing. Each song was known by the name given to its tune rather than by a title drawn from the text."

text: "Shape-note singers used

text: tune book

text: s rather than

text: hymnal

text: s. Hymnals were pocket-size books with texts only. Tune books were large oblong-shaped books with hard covers (nine inches by six inches was a typical size), often running to over four hundred pages. They included both music and text and were introduced by an extended essay on the rudiments of singing. Each song was known by the name given to its tune rather than by a title drawn from the text."

text: Spiral galaxies are named for the spiral structures that extend from the center into the galactic disc. The spiral arms are sites of ongoing star formation and are brighter than the surrounding disc because of the young, hot OB stars that inhabit them.

text: Spiral galaxies are named for the spiral structures that extend from the center into the

text: galactic disc

text: . The spiral arms are sites of ongoing star formation and are brighter than the surrounding disc because of the young, hot

text: OB star

text: s that inhabit them.

text: Optical light is still the primary means by which astronomy occurs, and in the context of cosmology, this means observing distant galaxies and galaxy clusters in order to learn about the large scale structure of the Universe as well as galaxy evolution. Redshift surveys have been a common means by which this has been accomplished with some of the most famous including the 2dF Galaxy Redshift Survey, the Sloan Digital Sky Survey, and the upcoming Large Synoptic Survey Telescope. These optical observations generally use either photometry or spectroscopy to measure the redshift of a galaxy and then, via Hubble's Law, determine its distance modulo redshift distortions due to peculiar velocities. Additionally, the position of the galaxies as seen on the sky in celestial coordinates can be used to gain information about the other two spatial dimensions.

text: Optical light is still the primary means by which astronomy occurs, and in the context of cosmology, this means observing distant galaxies and galaxy clusters in order to learn about the

text: large scale structure

text: of the Universe as well as

text: galaxy evolution

text: Redshift survey

text: s have been a common means by which this has been accomplished with some of the most famous including the

text: 2dF Galaxy Redshift Survey

text: , the

text: Sloan Digital Sky Survey

text: , and the upcoming

text: Large Synoptic Survey Telescope

text: . These optical observations generally use either

text: photometry

text: or

text: spectroscopy

text: to measure the

text: redshift

text: of a galaxy and then, via

text: Hubble's Law

text: , determine its distance modulo redshift distortions due to

text: peculiar velocities

text: . Additionally, the position of the galaxies as seen on the sky in

text: celestial coordinates

text: can be used to gain information about the other two spatial dimensions.

text: The Goa'uld are the dominant race in the Milky Way and the primary adversaries from seasons 1 to 8 of Stargate SG-1. They are a parasitic species that resemble finned snakes, which can burrow themselves into a humanoid's neck and wrap around the spinal column. The Goa'uld symbiote then takes control of its host's body and mind, while providing longevity and perfect health. Thousands of years ago, the Goa'uld ruled over Earth, masquerading as gods from ancient mythologies. They transplanted humans throughout the galaxy to serve as slaves and hosts, and they created the Jaffa to serve as incubators for their larvae. The most powerful Goa'uld in the galaxy are collectively known as the System Lords.

text: The Goa'uld are the dominant race in the Milky Way and the primary adversaries from seasons 1 to 8 of Stargate SG-1. They are a parasitic species that resemble finned snakes, which can burrow themselves into a humanoid's neck and wrap around the spinal column. The Goa'uld symbiote then takes control of its host's body and mind, while providing longevity and perfect health. Thousands of years ago, the Goa'uld ruled over Earth, masquerading as gods from ancient mythologies. They transplanted humans throughout the galaxy to serve as slaves and hosts, and they created the Jaffa to serve as incubators for their larvae. The most powerful Goa'uld in the galaxy are collectively known as the

text: System Lords

text: CL J1001+0220 is, as of 2016, the most distant known galaxy cluster. Discovered in 2016 by the Chandra X-ray Observatory in conjunction with the ESO's UltraVISTA telescope and the Atacama Large Millimeter Array, it has a redshift of z=2.506, placing it at a distance of 11.1 billion light-years from Earth. The galaxy cluster appears to be undergoing the transformation from a galaxy cluster that is still forming, a proto-cluster, to a mature cluster, and it is the first such cluster observed in this stage of its evolution. The cluster consists of seventeen galaxies, and nine of the eleven massive galaxies closest to its centre have new stars forming in them at a very high rate, equivalent to about 3,400 Suns per year. In contrast, the Milky Way produces only the equivalent of one Sun per year, so these galaxies at the core of the cluster are producing stars at a rate three hundred times greater than the Milky Way on average. Other galaxy clusters at ten billion light years and closer have far less star formation, and this suggests that star formation slows down in large galaxies within clusters after the galaxies have already come together during the development of a galaxy cluster.

text: CL J1001+0220 is, as of 2016, the most distant known

text: galaxy cluster

text: . Discovered in 2016 by the

text: Chandra X-ray Observatory

text: in conjunction with the ESO's

text: UltraVISTA

text: telescope and the

text: Atacama Large Millimeter Array

text: , it has a

text: redshift

text: of z=2.506, placing it at a distance of 11.1 billion

text: light-year

text: s from Earth. The galaxy cluster appears to be undergoing the transformation from a galaxy cluster that is still forming, a proto-cluster, to a mature cluster, and it is the first such cluster observed in this stage of its evolution. The cluster consists of seventeen galaxies, and nine of the eleven massive galaxies closest to its centre have new stars forming in them at a very high rate, equivalent to about 3,400

text: Sun

text: s per year. In contrast, the

text: Milky Way

text: produces only the equivalent of one

text: Sun

text: per year, so these galaxies at the core of the cluster are producing stars at a rate three hundred times greater than the Milky Way on average. Other galaxy clusters at ten billion light years and closer have far less star formation, and this suggests that star formation slows down in large galaxies within clusters after the galaxies have already come together during the development of a galaxy cluster.

text: This is a partial list of novae in the Milky Way galaxy that have been discovered and recorded since 1891. Novae are stars that undergo dramatic explosions, but unlike supernovae, these do not result in the destruction of the original star. The likely rate of novae in the Milky Way is about 40 per year, but of these only about 10 per year are discovered by observers as of the 2000s (decade). This list attempts to include only the brighter or more notable novae.

text: This is a partial list of

text: nova

text: e in the

text: Milky Way

text: galaxy that have been discovered and recorded since 1891.

text: Nova

text: e are stars that undergo dramatic explosions, but unlike supernovae, these do not result in the destruction of the original star. The likely rate of novae in the Milky Way is about 40 per year, but of these only about 10 per year are discovered by observers as of the 2000s (decade). This list attempts to include only the brighter or more notable novae.

text: Blue blobs are clusters of stars outside galaxies that are possibly formed from gas collisions and subsequent turbulence. On January 2008, the Hubble Space Telescope detected these clusters among three colliding galaxies.

text: Blue blobs are clusters of

text: star

text: s outside galaxies that are possibly formed from gas collisions and subsequent turbulence. On January 2008, the

text: Hubble Space Telescope

text: detected these clusters among three colliding

text: galaxies

text: NGC 5033 and the nearby spiral galaxy NGC 5005 comprise a physical galaxy pair.  The two galaxies weakly influence each other gravitationally, but they are not yet close enough to each other to be distorted by the tidal forces of the gravitational interaction. The fainter Irregular galaxy IC 4182 is also a member of this group.

text: NGC 5033 and the nearby spiral galaxy

text: NGC 5005

text: comprise a physical galaxy pair.  The two galaxies weakly influence each other gravitationally, but they are not yet close enough to each other to be distorted by the tidal forces of the gravitational interaction. The fainter

text: Irregular galaxy

text: IC 4182 is also a member of this group.

text: All stars form in clusters, but most clusters break up less than 50 million years after star formation concludes. The astronomical term for this process is "evaporation." Only extremely massive clusters, orbiting far from the Galactic center, can avoid evaporation over extended timescales. As one such survivor, the Hyades Cluster probably contained a much larger star population in its infancy. Estimates of its original mass range from 800 to 1600 times the mass of our Sun (), implying still larger numbers of individual stars.

text: All stars form in clusters, but most clusters break up less than 50 million years after star formation concludes. The astronomical term for this process is "

text: evaporation

text: ." Only extremely massive clusters, orbiting far from the

text: Galactic center

text: , can avoid evaporation over extended timescales. As one such survivor, the Hyades Cluster probably contained a much larger star population in its infancy. Estimates of its original mass range from 800 to 1600 times the

text: mass of our Sun

text: (), implying still larger numbers of individual stars.

text: Early work on what was originally believed to be simply a new category of novae was performed during the 1930s by two astronomers named  Walter Baade and Fritz Zwicky at Mount Wilson Observatory. The name super-novae was first used during 1931 lectures held at Caltech by Baade and Zwicky, then used publicly in 1933 at a meeting of the American Physical Society. By 1938, the hyphen had been lost and the modern name was in use. Because supernovae are relatively rare events within a galaxy, occurring about three times a century in the Milky Way, obtaining a good sample of supernovae to study requires regular monitoring of many galaxies.

text: Early work on what was originally believed to be simply a new category of

text: nova

text: e was performed during the 1930s by two astronomers named

text: Walter Baade

text: and

text: Fritz Zwicky

text: at Mount Wilson Observatory. The name super-novae was first used during 1931 lectures held at

text: Caltech

text: by Baade and Zwicky, then used publicly in 1933 at a meeting of the

text: American Physical Society

text: . By 1938, the hyphen had been lost and the modern name was in use. Because supernovae are relatively rare events within a galaxy, occurring about three times a century in the Milky Way, obtaining a good sample of supernovae to study requires regular monitoring of many galaxies.

text: The Tucana Dwarf is located in the constellation Tucana. It is about  away, on the opposite side of the Milky Way galaxy to most of the other Local Group galaxies and is therefore important for understanding the kinematics and formation history of the Local Group, as well as the role of environment in determining how dwarf galaxies evolve. It is isolated from other galaxies, and located near the edge of the Local Group, around  from the barycentre of the Local Group—the second most remote of all member galaxies after the Sagittarius Dwarf Irregular Galaxy.

text: The Tucana Dwarf is located in the constellation Tucana. It is about  away, on the opposite side of the

text: Milky Way

text: galaxy to most of the other

text: Local Group

text: galaxies and is therefore important for understanding the kinematics and formation history of the Local Group, as well as the role of environment in determining how dwarf galaxies evolve. It is isolated from other galaxies, and located near the edge of the Local Group, around  from the barycentre of the Local Group—the second most remote of all member galaxies after the

text: Sagittarius Dwarf Irregular Galaxy

text: Star clusters or star clouds are groups of stars. Two types of star clusters can be distinguished: globular clusters are tight groups of hundreds or thousands of very old stars which are gravitationally bound, while open clusters, more loosely clustered groups of stars, generally contain fewer than a few hundred members, and are often very young. Open clusters become disrupted over time by the gravitational influence of giant molecular clouds as they move through the galaxy, but cluster members will continue to move in broadly the same direction through space even though they are no longer gravitationally bound; they are then known as a stellar association, sometimes also referred to as a moving group.

text: Star clusters or star clouds are groups of

text: star

text: s. Two types of star clusters can be distinguished:

text: globular cluster

text: s are tight groups of hundreds or thousands of very old stars which are

text: gravitation

text: ally bound, while

text: open cluster

text: s, more loosely clustered groups of stars, generally contain fewer than a few hundred members, and are often very young. Open clusters become disrupted over time by the gravitational influence of

text: giant molecular cloud

text: s as they move through the

text: galaxy

text: , but cluster members will continue to move in broadly the same direction through space even though they are no longer gravitationally bound; they are then known as a

text: stellar association

text: , sometimes also referred to as a moving group.

text: Galaxies have a variety of morphologies, with irregular, elliptical and disk-like shapes, depending on their formation and evolutionary histories, including interaction with other galaxies, which may lead to a merger. Disc galaxies encompass lenticular and spiral galaxies with features, such as spiral arms and a distinct halo. At the core, most galaxies have a supermassive black hole, which may result in an active galactic nucleus. Galaxies can also have satellites in the form of dwarf galaxies and globular clusters.

text: Galaxies have a variety of

text: morphologies

text: , with

text: irregular

text: elliptical

text: and

text: disk-like

text: shapes, depending on their formation and evolutionary histories, including

text: interaction

text: with other galaxies, which may lead to a

text: merger

text: . Disc galaxies encompass

text: lenticular

text: and

text: spiral galaxies

text: with features, such as

text: spiral arms

text: and a distinct

text: halo

text: . At the core, most galaxies have a

text: supermassive black hole

text: , which may result in an

text: active galactic nucleus

text: . Galaxies can also have satellites in the form of

text: dwarf galaxies

text: and

text: globular cluster

text: s.

text: In most cases, the borehole's circumference will not be a perfect circle and therefore a caliper tool with several arms is required to obtain a true understanding of the size and shape of the borehole.  The borehole can change to an oval shape after drilling, which can cause the caliper log to overestimate the size of the borehole if its arms get stuck axis.

text: The first Galaxy station, Galaxy Radio was launched in 1990 in South West England broadcasting from studios in Portland Square, Bristol on the 97.2 FM frequency. The station became a key rival to the city's GWR FM station and was operated by the Chiltern Radio Group under the "Hot FM" brand. In 1994, the station was awarded the license to broadcast on the new Severn Estuary frequency on 101 megahertz serving South Wales and the West of England areas and was rebranded as Galaxy 101. Chrysalis Radio purchased the station in 1996 and in 1997 expanded the network by buying the Faze FM operated stations which were Kiss 102 in Manchester (which became Galaxy Manchester) and Kiss 105 in Yorkshire (which became Galaxy Yorkshire) respectively. In 1998, black community station Choice FM was acquired in Birmingham and became Galaxy Birmingham. Chrysalis Radio scored another success in 1999 with the Radio Authority's award of the North East regional licence to Galaxy North East. However, Galaxy 101's success in Bristol was starting to falter, and the station was sold to the GWR Group in 2002, becoming Vibe 101 (now Kiss 101). On 7 November 2008, Xfm Scotland became Galaxy Scotland after Global Radio purchased GCap.

text: The first Galaxy station, Galaxy Radio was launched in 1990 in

text: South West England

text: broadcasting from studios in Portland Square,

text: Bristol

text: on the 97.2 FM frequency. The station became a key rival to the city's

text: GWR FM

text: station and was operated by the

text: Chiltern Radio Group

text: under the "Hot FM" brand. In 1994, the station was awarded the license to broadcast on the new Severn Estuary frequency on 101 megahertz serving South Wales and the West of England areas and was rebranded as

text: Galaxy 101

text: . Chrysalis Radio purchased the station in 1996 and in 1997 expanded the network by buying the

text: Faze FM

text: operated stations which were

text: Kiss 102

text: in Manchester (which became

text: Galaxy Manchester

text: ) and

text: Kiss 105

text: in Yorkshire (which became

text: Galaxy Yorkshire

text: ) respectively. In 1998, black community station

text: Choice FM

text: was acquired in Birmingham and became

text: Galaxy Birmingham

text: . Chrysalis Radio scored another success in 1999 with the

text: Radio Authority

text: 's award of the North East regional licence to

text: Galaxy North East

text: . However, Galaxy 101's success in

text: Bristol

text: was starting to falter, and the station was sold to the

text: GWR Group

text: in 2002, becoming

text: Vibe 101

text: (now

text: Kiss 101

text: ). On 7 November 2008, Xfm Scotland became

text: Galaxy Scotland

text: after Global Radio purchased GCap.

text: The bulk of the stars in a spiral galaxy are located either close to a single plane (the galactic plane) in more or less conventional circular orbits around the center of the galaxy (the Galactic Center), or in a spheroidal galactic bulge around the galactic core.

text: The bulk of the stars in a spiral galaxy are located either close to a single plane (the

text: galactic plane

text: ) in more or less conventional circular

text: orbit

text: s around the center of the galaxy (the

text: Galactic Center

text: ), or in a

text: spheroid

text: al galactic bulge around the galactic core.

text: NGC 4631 has a nearby companion dwarf elliptical galaxy, NGC 4627.  NGC 4627 and NGC 4631 together were listed in the Atlas of Peculiar Galaxies as an example of a "double galaxy" or a galaxy pair.

text: NGC 4631 has a nearby companion

text: dwarf elliptical galaxy

text: NGC 4627

text: .  NGC 4627 and NGC 4631 together were listed in the

text: Atlas of Peculiar Galaxies

text: as an example of a "double galaxy" or a galaxy pair.

text: There are over 1,000 known open clusters in our galaxy, but the true total may be up to ten times higher than that. In spiral galaxies, open clusters are largely found in the spiral arms where gas densities are highest and so most star formation occurs, and clusters usually disperse before they have had time to travel beyond their spiral arm. Open clusters are strongly concentrated close to the galactic plane, with a scale height in our galaxy of about 180 light years, compared to a galactic radius of approximately 50,000 light years.

text: There are over 1,000 known open clusters in our galaxy, but the true total may be up to ten times higher than that. In

text: spiral galaxies

text: , open clusters are largely found in the spiral arms where gas densities are highest and so most star formation occurs, and clusters usually disperse before they have had time to travel beyond their spiral arm. Open clusters are strongly concentrated close to the galactic plane, with a

text: scale height

text: in our galaxy of about 180 light years, compared to a galactic radius of approximately 50,000 light years.

text: NGC 1156 is a dwarf irregular galaxy in the Aries constellation of the type . It is considered a Magellanic-type irregular. The galaxy has a larger than average core, and contains zones of contra-rotating gas. The counter-rotation is thought to be the result of tidal interactions with another gas rich galaxy some time in the past.

text: NGC 1156 is a

text: dwarf

text: irregular

text: galaxy

text: in the

text: Aries constellation

text: of the type . It is considered a Magellanic-type irregular. The galaxy has a larger than average core, and contains zones of contra-rotating gas. The counter-rotation is thought to be the result of tidal interactions with another gas rich galaxy some time in the past.

text: The Hyades Cluster is related to other stellar groups in the Sun's vicinity.  Its age, metallicity, and proper motion coincide with those of the larger and more distant Praesepe Cluster, and the trajectories of both clusters can be traced back to the same region of space, indicating a common origin. Another associate is the Hyades Stream, a large collection of scattered stars that also share a similar trajectory with the Hyades Cluster. Recent results have found that at least 15% of stars in the Hyades stream share the same chemical fingerprint as the Hyades cluster stars. However, about 85% of stars in the Hyades Stream have been shown to be completely unrelated to the original cluster on the grounds of dissimilar age and metallicity; their common motion is attributed to tidal effects of the massive rotating bar at the center of the Milky Way Galaxy. Among the remaining members of the Hyades Stream, the exoplanet host star Iota Horologii has recently been proposed as an escaped member of the primordial Hyades Cluster.

text: The Hyades Cluster is related to other stellar groups in the Sun's vicinity.  Its age, metallicity, and

text: proper motion

text: coincide with those of the larger and more distant

text: Praesepe Cluster

text: , and the trajectories of both clusters can be traced back to the same region of space, indicating a common origin. Another associate is the

text: Hyades Stream

text: , a large collection of scattered stars that also share a similar trajectory with the Hyades Cluster. Recent results have found that at least 15% of stars in the Hyades stream share the same chemical fingerprint as the Hyades cluster stars. However, about 85% of stars in the Hyades Stream have been shown to be completely unrelated to the original cluster on the grounds of dissimilar age and metallicity; their common motion is attributed to tidal effects of the massive rotating

text: bar

text: at the center of the

text: Milky Way Galaxy

text: . Among the remaining members of the Hyades Stream, the

text: exoplanet

text: host star

text: Iota Horologii

text: has recently been proposed as an escaped member of the primordial Hyades Cluster.

text: Galaxies that contain LINERs are often referred to as LINER galaxies.  LINER galaxies are very common; approximately one-third of all nearby galaxies (galaxies within approximately 20-40 Mpc) may be classified as LINER galaxies.  Approximately 75% of LINER galaxies are either elliptical galaxies, lenticular galaxies, or S0/a-Sab galaxies (spiral galaxies with large bulges and tightly wound spiral arms).  LINERs are found less frequently in Sb-Scd galaxies (spiral galaxies with small bulges and loosely wound spiral arms), and they are very rare in nearby irregular galaxies.  LINERs also may be commonly found in luminous infrared galaxies (LIRGs), a class of galaxies defined by their infrared luminosities that are frequently formed when two galaxies collide with each other. Approximately one-quarter of LIRGs may contain LINERs.

text: Galaxies that contain LINERs are often referred to as LINER galaxies.  LINER galaxies are very common; approximately one-third of all nearby galaxies (galaxies within approximately 20-40

text: Mpc

text: ) may be classified as LINER galaxies.  Approximately 75% of LINER galaxies are either

text: elliptical galaxies

text: lenticular galaxies

text: , or S0/a-Sab galaxies (

text: spiral galaxies

text: with large bulges and tightly wound spiral arms).  LINERs are found less frequently in Sb-Scd galaxies (spiral galaxies with small bulges and loosely wound spiral arms), and they are very rare in nearby

text: irregular galaxies

text: .  LINERs also may be commonly found in

text: luminous infrared galaxies

text: (LIRGs), a class of galaxies defined by their

text: infrared

text: luminosities

text: that are frequently formed when two galaxies

text: collide

text: with each other. Approximately one-quarter of LIRGs may contain LINERs.

text: Samsung WatchON, first introduced on Galaxy S4 devices, was a service that allowed users to view programming information on their TV or set-top box, and choose programs directly from their mobile devices. Samsung WatchON also provides real-time programming and VOD content recommendations based on the user's viewing patterns; it also includes a virtual remote controller which uses the built-in IR Blaster of the device to control televisions, home theater systems, and media players of any brand, provided they are IR compatible. Samsung WatchON is available on the Galaxy S4, Galaxy S4 Mini, Galaxy S5, Galaxy S5 Mini, Galaxy Note 3, Galaxy Note 3 Neo, Galaxy Note 4, Galaxy Note Edge, Galaxy Alpha, Galaxy Note 8.0, Galaxy Note 10.1, Galaxy Note 10.1 2014 Edition, Galaxy Note Pro 12.2, Galaxy Tab 2 7.0, Galaxy Tab 2 10.1, Galaxy Tab 3 7.0, Galaxy Tab 3 8.0, Galaxy Tab 3 10.1, Galaxy Tab 4 7.0, Galaxy Tab 4 8.0, Galaxy Tab 4 10.1, Galaxy Tab Pro 8.4, Galaxy Tab Pro 10.1, Galaxy Tab Pro 12.2, Galaxy Tab S 8.4, Galaxy Tab S 10.5, and Gear 2 devices.

text: Samsung WatchON, first introduced on

text: Galaxy S4

text: devices, was a service that allowed users to view programming information on their TV or set-top box, and choose programs directly from their mobile devices. Samsung WatchON also provides real-time programming and

text: VOD

text: content recommendations based on the user's viewing patterns; it also includes a virtual remote controller which uses the built-in

text: IR

text: Blaster of the device to control televisions, home theater systems, and media players of any brand, provided they are IR compatible. Samsung WatchON is available on the

text: Galaxy S4

text: Galaxy S4 Mini

text: Galaxy S5

text: Galaxy S5 Mini

text: Galaxy Note 3

text: Galaxy Note 3 Neo

text: Galaxy Note 4

text: Galaxy Note Edge

text: Galaxy Alpha

text: Galaxy Note 8.0

text: Galaxy Note 10.1

text: Galaxy Note 10.1 2014 Edition

text: Galaxy Note Pro 12.2

text: Galaxy Tab 2 7.0

text: Galaxy Tab 2 10.1

text: Galaxy Tab 3 7.0

text: Galaxy Tab 3 8.0

text: Galaxy Tab 3 10.1

text: Galaxy Tab 4 7.0

text: Galaxy Tab 4 8.0

text: Galaxy Tab 4 10.1

text: Galaxy Tab Pro 8.4

text: Galaxy Tab Pro 10.1

text: Galaxy Tab Pro 12.2

text: Galaxy Tab S 8.4

text: Galaxy Tab S 10.5

text: , and

text: Gear 2

text: devices.

text: While ellipticals and spirals tend to have somewhat well-defined Sérsic profiles, the surface brightness profiles of lenticular galaxies are often more difficult to quantify. The disk component of lenticular galaxies often has a very flat surface brightness distribution (Sérsic index of n ≈ 1), especially in the outermost regions of the disk. Also, there is typically an observed truncation in the surface brightness of lenticular galaxies at ~ 4 scale radii of the disk. These features are consistent with the general structure of spiral galaxies. However, the bulge component of lenticulars is more closely related to elliptical galaxies in terms of morphological classification. This spheroidal region, which dominates the overall structure of lenticular galaxies, has a much steeper surface brightness profile (Sérsic index of n ≈ 4, or that of a de Vaucouleurs profile) than the disk component. Since the bulge component tends to dominate the galaxy, lenticular galaxy samples are often indistinguishable from elliptical galaxy populations in terms of their overall surface brightness profiles. However, galaxies are often assigned the S0 morphological class when they require multiple Sérsic indices to describe their surface brightness profiles, one to describe the bulge and one to describe the disk. This implies that lenticular galaxies are a distinct morphological subclass of galaxies.

text: While ellipticals and spirals tend to have somewhat well-defined

text: Sérsic profiles

text: , the

text: surface brightness

text: profiles of lenticular galaxies are often more difficult to quantify. The disk component of lenticular galaxies often has a very flat surface brightness distribution (Sérsic index of n ≈ 1), especially in the outermost regions of the disk. Also, there is typically an observed truncation in the surface brightness of lenticular galaxies at ~ 4 scale radii of the disk. These features are consistent with the general structure of spiral galaxies. However, the bulge component of lenticulars is more closely related to elliptical galaxies in terms of morphological classification. This spheroidal region, which dominates the overall structure of lenticular galaxies, has a much steeper surface brightness profile (Sérsic index of n ≈ 4, or that of a

text: de Vaucouleurs profile

text: ) than the disk component. Since the bulge component tends to dominate the galaxy, lenticular galaxy samples are often indistinguishable from elliptical galaxy populations in terms of their overall surface brightness profiles. However, galaxies are often assigned the S0 morphological class when they require multiple Sérsic indices to describe their surface brightness profiles, one to describe the bulge and one to describe the disk. This implies that lenticular galaxies are a distinct morphological subclass of galaxies.

text: Hubble thought incorrectly that the tuning fork diagram described an evolutionary sequence for galaxies, from elliptical galaxies through lenticulars to spiral galaxies. However, astronomers now believe that disk galaxies likely formed first, then evolved into elliptical galaxies through galaxy mergers.

text: Hubble thought incorrectly that the tuning fork diagram described an evolutionary sequence for galaxies, from elliptical galaxies through

text: lenticulars

text: to spiral galaxies. However, astronomers now believe that disk galaxies likely formed first, then evolved into elliptical galaxies through galaxy mergers.

text: Scientists do not have much explanation for some astronomic events, so some use the idea of a dark galaxy to explain these events. Little is known about dark galaxies, and some scientists believe a dark galaxy is actually a newly forming galaxy. One such candidate is in the Virgo cluster. This candidate contains very few stars. Scientists classify this galaxy as a newly forming galaxy, rather than a dark galaxy.Scientists say that the galaxies we see today only began to create stars after dark galaxies. Based on numerous scientific assertions, dark galaxies played a big role in many of the galaxies astronomers and scientists see today. Martin Haehnel, from Kavli Institute for Cosmology at the University of Cambridge, claims that the precursor to the Milky Way galaxy was actually a much smaller bright galaxy that had merged with dark galaxies nearby to form the Milky Way we currently see. Multiple scientists agree that dark galaxies are building blocks of modern galaxies. Sebastian Cantalupo of the University of California, Santa Cruz, agrees with this theory. He goes on to say, "In our current theory of galaxy formation, we believe that big galaxies form from the merger of smaller galaxies. Dark galaxies bring to big galaxies a lot of gas, which then accelerates star formation in the bigger galaxies." Scientists have specific techniques they use to locate these dark galaxies. These techniques have the capability of teaching us more about other special events that occur in the universe; for instance, the “cosmic web”. This “web” is made of invisible filaments of gas and dark matter believed to permeate the universe, as well as “feeding and building galaxies and galaxy clusters where the filaments intersect.”

text: Scientists do not have much explanation for some astronomic events, so some use the idea of a dark galaxy to explain these events. Little is known about dark galaxies, and some scientists believe a dark galaxy is actually a newly forming galaxy. One such candidate is in the Virgo cluster. This candidate contains very few stars. Scientists classify this galaxy as a

text: newly forming galaxy

text: The Andromeda Galaxy is approaching the Milky Way at about . It has been measured approaching relative to our Sun at around  as the Sun orbits around the center of our galaxy at a speed of approximately . This makes the Andromeda Galaxy one of about 100 observable blueshifted galaxies. Andromeda Galaxy's tangential or side-ways velocity with respect to the Milky Way is relatively much smaller than the approaching velocity and therefore it is expected to directly collide with the Milky Way in about 4 billion years. A likely outcome of the collision is that the galaxies will merge to form a giant elliptical galaxy or perhaps even a large disc galaxy. Such events are frequent among the galaxies in galaxy groups. The fate of the Earth and the Solar System in the event of a collision is currently unknown. Before the galaxies merge, there is a small chance that the Solar System could be ejected from the Milky Way or join the Andromeda Galaxy.

text: The Andromeda Galaxy is approaching the

text: Milky Way

text: at about . It has been measured approaching relative to our Sun at around  as the Sun orbits around the center of our galaxy at a speed of approximately . This makes the Andromeda Galaxy one of about 100 observable

text: blueshift

text: ed galaxies. Andromeda Galaxy's tangential or side-ways velocity with respect to the Milky Way is relatively much smaller than the approaching velocity and therefore it is expected to directly collide with the Milky Way in about 4 billion years. A likely outcome of the collision is that the

text: galaxies will merge

text: to form a giant

text: elliptical galaxy

text: or perhaps even a large

text: disc galaxy

text: . Such events are frequent among the galaxies in

text: galaxy group

text: s. The fate of the

text: Earth

text: and the

text: Solar System

text: in the event of a collision is currently unknown. Before the galaxies merge, there is a small chance that the Solar System could be ejected from the Milky Way or join the Andromeda Galaxy.

text: The Pegasus Dwarf Irregular Galaxy (also known as Peg DIG or the Pegasus Dwarf) is a dwarf irregular galaxy in the direction of the constellation Pegasus. It was discovered by A. G. Wilson in the 1950s. The Pegasus Dwarf is a companion of the Andromeda Galaxy in the Local Group.

text: The Pegasus Dwarf Irregular Galaxy (also known as Peg DIG or the Pegasus Dwarf) is a

text: dwarf

text: irregular galaxy

text: in the direction of the

text: constellation

text: Pegasus

text: . It was discovered by

text: A. G. Wilson

text: in the 1950s. The Pegasus Dwarf is a companion of the

text: Andromeda Galaxy

text: in the

text: Local Group

text: In 1994, several stars were identified as having broad helium emission lines in their spectra, and some showed narrow hydrogen emission lines.  This was completely unexpected for protostars, instead suggesting the objects were much more evolved stars.  Shortly afterwards two emission line stars were classified as Wolf Rayet stars, and a third as a Luminous Blue Variable that was thought to be one of the most luminous stars in the galaxy.  A small number of red supergiants were also identified, narrowing the likely age of the cluster.

text: In 1994, several stars were identified as having broad

text: helium

text: emission lines in their spectra, and some showed narrow

text: hydrogen

text: emission lines.  This was completely unexpected for protostars, instead suggesting the objects were much more evolved stars.  Shortly afterwards two emission line stars were classified as Wolf Rayet stars, and a third as a Luminous Blue Variable that was thought to be one of the most luminous stars in the galaxy.  A small number of red supergiants were also identified, narrowing the likely age of the cluster.

text: Pisces Dwarf is an irregular dwarf galaxy that is part of the Local Group. The galaxy is also suspected of being a satellite galaxy of the Triangulum Galaxy.

text: Pisces Dwarf

text: is an irregular dwarf galaxy that is part of the

text: Local Group

text: . The galaxy is also suspected of being a satellite galaxy of the Triangulum Galaxy.

text: The central region of the galaxy is home to hundreds of massive, ultra-luminous clusters of young stars that appear as bluish knots of light. These young clusters were created on the suspected galaxy merger, that pushed gases into these regions and caused a burst of star formation.

text: The central region of the galaxy is home to hundreds of

text: massive, ultra-luminous clusters of young stars

text: that appear as bluish knots of light. These young clusters were created on the suspected galaxy merger, that pushed gases into these regions and caused a burst of star formation.

text: However, not all of these objects are interacting galaxies.  A few of these galaxies are simply nearby dwarf galaxies with irregular structure.

text: Most multiple-star systems are organized in what is called a hierarchical system: the stars in the system can be divided into two smaller groups, each of which traverses a larger orbit around the system's center of mass. Each of these smaller groups must also be hierarchical, which means that they must be divided into smaller subgroups which themselves are hierarchical, and so on. Each level of the hierarchy can be treated as a two-body problem by considering close pairs as if they were a single star. In these systems there is little interaction between the orbits and the stars' motion will continue to approximate stable Keplerian orbits around the system's center of mass, unlike the unstable trapezia systems or the even more complex dynamics of the large number of stars in star clusters and galaxies.

text: Most multiple-star systems are organized in what is called a hierarchical system: the stars in the system can be divided into two smaller groups, each of which traverses a larger orbit around the system's

text: center of mass

text: . Each of these smaller groups must also be hierarchical, which means that they must be divided into smaller subgroups which themselves are hierarchical, and so on. Each level of the hierarchy can be treated as a

text: two-body problem

text: by considering close pairs as if they were a single star. In these systems there is little interaction between the orbits and the stars' motion will continue to approximate stable

text: Keplerian

text: orbits around the system's center of mass, unlike the unstable

text: trapezia

text: systems or the even more complex

text: dynamics

text: of the large number of

text: star

text: s in

text: star cluster

text: s and

text: galaxies

text: The USS Enterprise (NCC-1701-E), staffed by its usual crew (except for Worf, who is on DS9), is on a mission from Starfleet Command, to assist Lem Faal, a Betazoid scientist, in breaching the barrier which encircles the Milky Way Galaxy. Along the way, Q interrupts them, warning Captain Picard to abandon his mission, with the usual warning of impending doom but no explanation.

text: The

text: USS Enterprise

text: (NCC-1701-E), staffed by its usual crew (except for

text: Worf

text: , who is on

entity_name: Deep Space Nine (fictional space station)

text: ), is on a mission from Starfleet Command, to assist Lem Faal, a

text: Betazoid

text: scientist, in breaching the barrier which encircles the Milky Way Galaxy. Along the way, Q interrupts them, warning

text: Captain Picard

text: to abandon his mission, with the usual warning of impending doom but no explanation.

text: Materials are important as well. A pipe filled with hair restricts the flow of water more than a clean pipe of the same shape and size. Similarly, electrons can flow freely and easily through a copper wire, but cannot flow as easily through a steel wire of the same shape and size, and they essentially cannot flow at all through an insulator like rubber, regardless of its shape. The difference between, copper, steel, and rubber is related to their microscopic structure and electron configuration, and is quantified by a property called resistivity.

text: Materials are important as well. A pipe filled with hair restricts the flow of water more than a clean pipe of the same shape and size. Similarly,

text: electron

text: s can flow freely and easily through a

text: copper

text: wire, but cannot flow as easily through a

text: steel

text: wire of the same shape and size, and they essentially cannot flow at all through an

text: insulator

text: like

text: rubber

text: , regardless of its shape. The difference between, copper, steel, and rubber is related to their microscopic structure and

text: electron configuration

text: , and is quantified by a property called

text: resistivity

text: Astronomers now see elliptical galaxies as some of the most evolved systems in the universe. It is widely accepted that the main driving force for the evolution of elliptical galaxies is mergers of smaller galaxies. Many galaxies in the universe are gravitationally bound to other galaxies, which means that they will never escape the pull of the other galaxy. If the galaxies are of similar size, the resultant galaxy will appear similar to neither of the two galaxies merging, but will instead be an elliptical galaxy. There are many types of galaxy mergers, which do not necessarily result in elliptical galaxies, but result in a change in the structure of the mergers. For example, a minor merger event is thought to be occurring between the Milky Way and the Magellanic Clouds.

text: Astronomers now see elliptical galaxies as some of the most evolved systems in the universe. It is widely accepted that the main driving force for the evolution of elliptical galaxies is

text: mergers

text: of smaller galaxies. Many galaxies in the universe are gravitationally bound to other galaxies, which means that they will never escape the pull of the other galaxy. If the galaxies are of similar size, the resultant galaxy will appear similar to neither of the two galaxies merging, but will instead be an elliptical galaxy. There are many types of galaxy mergers, which do not necessarily result in elliptical galaxies, but result in a change in the structure of the mergers. For example, a minor merger event is thought to be occurring between the Milky Way and the Magellanic Clouds.

text: The afterglow of GRB 970508 reached a peak total luminosity 19.82 days after the burst was detected. It then faded with a power law slope over about 100 days. The afterglow eventually disappeared, revealing the burst's host, an actively star-forming dwarf galaxy with an apparent magnitude of V = 25.4 ± 0.15. The galaxy was well fitted by an exponential disk with an ellipticity of 0.70 ± 0.07. The redshift of GRB 970508's optical afterglow, z = 0.835, agreed with the host galaxy's redshift of z = 0.83, suggesting that, unlike previously observed bursts, GRB 970508 may have been associated with an active galactic nucleus.

text: The afterglow of GRB 970508 reached a peak total luminosity 19.82 days after the burst was detected. It then faded with a

text: power law

text: slope over about 100 days. The afterglow eventually disappeared, revealing the burst's host, an actively star-forming dwarf galaxy with an

text: apparent magnitude

text: of V = 25.4 ± 0.15. The galaxy was well fitted by an

text: exponential disk

text: with an

text: ellipticity

text: of 0.70 ± 0.07. The redshift of GRB 970508's optical afterglow, z = 0.835, agreed with the host galaxy's redshift of z = 0.83, suggesting that, unlike previously observed bursts, GRB 970508 may have been associated with an

text: active galactic nucleus

text: Among the variable stars are RR Lyraes and Cepheids, which are well-understood distance indicators that will provide the 3rd dimension on the 3-D map of the surveyed region that will yield important information on the ages of the populations.A comparison between the RR Lyrae and type II Cepheids in the field and in globular clusters may hold precious information about the formation of the bulge (e.g. Feast et al., 2008). Modern ΛCDM cosmology predicts that large galaxies such as the Milky Way formed by accretion of hundreds of smaller “protogalactic fragments”, perhaps not unlike the progenitors of the present-day dwarf spheroidal satellites (e.g., Abadi et al., 2003) Interestingly, two very massive globular clusters in the Galactic bulge, NGC 6388 and NGC 6441, have recently been suggested to be the remnants of dwarf galaxies that were accreted in the course of the Galaxy’s history (Ree et al., 2002). These clusters might prove similar to the cases of M54 (NGC 6715), in the center of the Sgr dSph, which is currently being cannibalised by the Milky Way (Ibata et al., 1995), and of ω Cen (NGC 5139), which has long been suspected to be the remnant nucleus of a dwarf galaxy (e.g., Altmann et al., 2005, and references therein). Our proposed search for RR Lyrae and type II Cepheids in the Galactic bulge will reveal the presence of debris related to the accretion events that might have left behind NGC 6441 as remnant object. The latter is part of our survey.

text: The spiral galaxy, NGC4622 (also called backward galaxy), lies 111 million light years away in the constellation Centaurus.    NGC 4622 is an example of a galaxy with leading spiral arms.  In spiral galaxies, spiral arms were thought to trail; the tips of the spiral arms winding away from the center of the galaxy in the direction of the disks orbital rotation. In NGC4622, however, the outer arms are leading spiral arms; the tips of the spiral arms point towards the direction of disk rotation. This may be the result of a gravitational interaction between NGC 4622 and another galaxy or the result of a merger between NGC 4622 and a smaller object.

text: The spiral galaxy, NGC4622 (also called backward galaxy), lies 111 million light years away in the constellation Centaurus.    NGC 4622 is an example of a galaxy with leading

text: spiral arm

text: s.  In spiral galaxies, spiral arms were thought to trail; the tips of the spiral arms winding away from the center of the galaxy in the direction of the disks orbital rotation. In NGC4622, however, the outer arms are leading spiral arms; the tips of the spiral arms point towards the direction of disk rotation. This may be the result of a gravitational interaction between NGC 4622 and another galaxy or the result of a merger between NGC 4622 and a smaller object.

text: Galaxies in this category are referred to by Arp as galaxies that are neither spiral nor elliptical in shape. Although he does not use the term "amorphous" to describe these galaxies, it is the best description of these galaxies.

text: Fission is also proposed as a possible explanation for the formation of close binary stars and explosions for the formation of galaxies and galaxy clusters

text: The story begins when a pair of aliens who call themselves Zeke and Simon arrive on Earth, landing their little red spaceship on a rural stretch of road in southern Arizona. The president sends his science advisor Kathy Stratton and chief of staff Ray Corbett to Arizona to find out who the aliens are and what they want. Simon and Zeke offer a business proposal that, they claim, will bring untold riches to the people of Earth. According to Zeke and Simon, humankind is the only Blood species (sentience) in the Milky Way galaxy, and thus owns it. Every star, every planet, every pebble in the galaxy belongs to the people of earth. Other species will be wanting to colonize planets in the newly discovered galaxy, and they’ll have to pay for leasehold rights. Under the partnership proposal, Zeke and Simon will negotiate those deals and split the profits with the people of Earth.

text: A flocculent spiral galaxy is a type of spiral galaxy. Unlike the well-defined spiral architecture of a grand design spiral galaxy, flocculent (meaning "fluffy") galaxies are patchy, with discontinuous spiral arms. Approximately 30% of spirals are flocculent, 10% are grand design, and the rest are referred to as "multi-armed". The multiple-arm type is sometimes grouped into the flocculent category.

text: A flocculent spiral galaxy is a type of

text: spiral galaxy

text: . Unlike the well-defined spiral architecture of a

text: grand design spiral galaxy

text: flocculent

text: (meaning "fluffy") galaxies are patchy, with discontinuous

text: spiral arm

text: s. Approximately 30% of spirals are flocculent, 10% are grand design, and the rest are referred to as "multi-armed". The multiple-arm type is sometimes grouped into the flocculent category.

text: The morphology and kinematics of lenticular galaxies each, to a degree, suggest a mode of galaxy formation. Their disk-like, possibly dusty, appearance suggests they come from faded spiral galaxies, whose arm features disappeared. Alternatively, as lenticular galaxies are likely to be more luminous than spiral galaxies, which suggests that they are not merely the faded remnants of spiral galaxies. Rather, lenticular galaxies might result from galaxy merger, which increase the total stellar mass and give the newly merged galaxy its disk-like, arm-less appearance.Recent research suggest that the evolution of luminous lenticular galaxies may be closely linked to that of elliptical galaxies, whereas fainter lenticulars might be more closely associated with ram-pressure stripped spiral galaxies.

text: The morphology and kinematics of lenticular galaxies each, to a degree, suggest a mode of

text: galaxy formation

text: . Their disk-like, possibly dusty, appearance suggests they come from faded

text: spiral galaxies

text: , whose arm features disappeared. Alternatively, as lenticular galaxies are likely to be more luminous than spiral galaxies, which suggests that they are not merely the faded remnants of spiral galaxies. Rather, lenticular galaxies might result from

text: galaxy merger

text: , which increase the total stellar mass and give the newly merged galaxy its disk-like, arm-less appearance.Recent research suggest that the evolution of luminous lenticular galaxies may be closely linked to that of elliptical galaxies, whereas fainter lenticulars might be more closely associated with ram-pressure stripped spiral galaxies.

text: An anemic galaxy is a type of spiral galaxy characterized by a low contrast between its spiral arms and its disk.

text: An anemic galaxy is a type of

text: spiral

text: galaxy

text: characterized by a low contrast between its

text: spiral arm

text: s and its disk.

text: The application of Newton's law of gravity has enabled the acquisition of much of the detailed information we have about the planets in the Solar System, the mass of the Sun, and details of quasars; even the existence of dark matter is inferred using Newton's law of gravity. Although we have not traveled to all the planets nor to the Sun, we know their masses. These masses are obtained by applying the laws of gravity to the measured characteristics of the orbit. In space an object maintains its orbit because of the force of gravity acting upon it. Planets orbit stars, stars orbit galactic centers, galaxies orbit a center of mass in clusters, and clusters orbit in superclusters. The force of gravity exerted on one object by another is directly proportional to the product of those objects' masses and inversely proportional to the square of the distance between them.

text: The application of Newton's law of gravity has enabled the acquisition of much of the detailed information we have about the planets in the Solar System, the mass of the Sun, and details of

text: quasar

text: s; even the existence of

text: dark matter

text: is inferred using Newton's law of gravity. Although we have not traveled to all the planets nor to the Sun, we know their masses. These masses are obtained by applying the laws of gravity to the measured characteristics of the orbit. In space an object maintains its

text: orbit

text: because of the force of gravity acting upon it. Planets orbit stars, stars orbit

text: galactic center

text: s,

text: galaxies

text: orbit a center of mass in clusters, and clusters orbit in

text: supercluster

text: s. The force of gravity exerted on one object by another is directly proportional to the product of those objects' masses and inversely proportional to the square of the distance between them.

text: This galaxy is similar in size and brightness, and often compared to, the Milky Way's satellite galaxy, the Large Magellanic Cloud (LMC). NGC 4449 has a general bar shape, also characteristic of the LMC, with scattered young blue star clusters.

text: This galaxy is similar in size and brightness, and often compared to, the Milky Way's

text: satellite galaxy

text: , the

text: Large Magellanic Cloud

text: (LMC). NGC 4449 has a general bar shape, also characteristic of the LMC, with scattered young blue

text: star clusters

text: The Sagittarius Dwarf Spheroidal Galaxy (Sgr dSph), also known as the Sagittarius Dwarf Elliptical Galaxy (Sgr dE or Sag DEG), is an elliptical loop-shaped satellite galaxy of the Milky Way. It consists of four globular clusters, the main cluster having been discovered in 1994. Sgr dSph is roughly 10,000 light-years in diameter, and is currently about 70,000 light-years from Earth, travelling in a polar orbit (i.e. an orbit passing over the Milky Way’s galactic poles) at a distance of about 50,000 light-years from the core of the Milky Way (about 1/3 the distance of the Large Magellanic Cloud). In its looping, spiraling path, it has passed through the plane of the Milky Way several times in the past.

text: The Sagittarius Dwarf Spheroidal Galaxy (Sgr dSph), also known as the Sagittarius Dwarf Elliptical Galaxy (Sgr dE or Sag DEG), is an

text: elliptical

text: loop-shaped

text: satellite galaxy

text: of the

text: Milky Way

text: . It consists of four

text: globular cluster

text: s, the main cluster having been discovered in 1994. Sgr dSph is roughly 10,000

text: light-year

text: s in diameter, and is currently about 70,000 light-years from

text: Earth

text: , travelling in a polar orbit (i.e. an orbit passing over the

text: Milky Way’s galactic poles

text: ) at a distance of about 50,000 light-years from the core of the Milky Way (about 1/3 the distance of the

text: Large Magellanic Cloud

text: ). In its looping, spiraling path, it has passed through the plane of the Milky Way several times in the past.

text: The SPRC is the Sloan Polar-Ring Catalogue, an atlas of 157 polar-ring galaxies. It was put together with images from the Sloan Digital Sky Survey.There are four sections (A,B,C, and D). There are 6 galaxies in section A which are kinematically confirmed galaxies. There are 27 in section B, which are good candidates. In section C, there are 73 galaxies, which are possible candidates. And there are 51 galaxies in section D, which are related objects.

text: The SPRC is the Sloan Polar-Ring Catalogue, an atlas of 157 polar-ring galaxies. It was put together with images from the

text: Sloan Digital Sky Survey

text: .There are four sections (A,B,C, and D). There are 6 galaxies in section A which are kinematically confirmed galaxies. There are 27 in section B, which are good candidates. In section C, there are 73 galaxies, which are possible candidates. And there are 51 galaxies in section D, which are related objects.

text: To account for the anomalous rotation curves of spiral galaxies, Milgrom proposed a modification of this force law in the form

text: This galaxy is one of the most massive in the local Universe. This galaxy spans a diameter of 120,000 light years, about the same as the Milky Way. But M87 is a spheroid, not a flat spiral. So it contains close to 2.7 trillion solar masses by some estimates. The mass of M87 within a radius of  from the core steadily increases roughly in proportion to r, where r is the radius from the core. Within a radius of , the mass is  times the mass of the Sun, which is double the mass of the Milky Way galaxy. Only a fraction of this mass is in the form of stars, as M87 has an estimated mass to luminosity ratio of . That is, about one part in six of the galaxy's mass is in the form of stars that are radiating energy. The total mass of M87 may be 200 times that of the Milky Way.

text: This galaxy is one of the most massive in the

text: local Universe

text: . This galaxy spans a diameter of 120,000 light years, about the same as the Milky Way. But M87 is a spheroid, not a flat spiral. So it contains close to 2.7 trillion solar masses by some estimates. The mass of M87 within a radius of  from the core steadily increases roughly

text: in proportion

text: to r, where r is the radius from the core. Within a radius of , the mass is  times the

text: mass of the Sun

text: , which is double the mass of the

text: Milky Way

text: galaxy. Only a fraction of this mass is in the form of stars, as M87 has an estimated mass to luminosity ratio of . That is, about one part in six of the galaxy's mass is in the form of stars that are radiating energy. The total mass of M87 may be 200 times that of the Milky Way.

text: Dwarf elliptical galaxies have blue absolute magnitudes within the range −18 mag < M < −14 mag, fainter than giant elliptical galaxies. While the surface brightness profiles of giant elliptical galaxies are well described by de Vaucouleur's law, dEs have exponentially declining surface brightness profiles. However, both types can be well fit by the same more general law, Sersic's law, and there is a continuity of Sersic index as a function of luminosity, suggesting that dwarf and giant elliptical galaxies belong to a single sequence. Still fainter elliptical-like galaxies, called dwarf spheroidal galaxies, appear to be genuinely distinct.

text: Dwarf elliptical galaxies have blue

text: absolute magnitude

text: s within the range −18 mag < M < −14 mag, fainter than giant elliptical galaxies. While the surface brightness profiles of

text: giant elliptical galaxies

text: are well described by

text: de Vaucouleur's law

text: , dEs have exponentially declining surface brightness profiles. However, both types can be well fit by the same more general law,

text: Sersic's law

text: , and there is a continuity of Sersic index as a function of luminosity, suggesting that dwarf and giant elliptical galaxies belong to a single sequence. Still fainter elliptical-like galaxies, called

text: dwarf spheroidal galaxies

text: , appear to be genuinely distinct.

text: It has been estimated that the nearby Fornax and Virgo galaxy clusters may contain hundreds or thousands of HCSSs. These galaxy clusters have been surveyed for compact galaxies and star clusters. It is possible that some of the objects picked up in these surveys were HCSSs that were misidentified as ordinary star clusters. A few of the compact objects in the surveys are known to have rather high internal velocities, but none appear to be massive enough to qualify as HCSSs.

text: It has been estimated that the nearby

text: Fornax

text: and

text: Virgo

text: galaxy clusters may contain hundreds or thousands of HCSSs. These galaxy clusters have been surveyed for compact galaxies and star clusters. It is possible that some of the objects picked up in these surveys were HCSSs that were misidentified as ordinary star clusters. A few of the compact objects in the surveys are known to have rather high internal velocities, but none appear to be massive enough to qualify as HCSSs.

text: The M74 Group (also known as the NGC 628 Group) is a small group of galaxies in the constellation Pisces.  The face-on spiral galaxy M74 (NGC 628) is the brightest galaxy within the group.  Other members include the peculiar spiral galaxy NGC 660 and several smaller irregular galaxies.

text: The M74 Group (also known as the NGC 628 Group) is a small

text: group of galaxies

text: in the

text: constellation

text: Pisces

text: .  The face-on

text: spiral galaxy

text: M74 (NGC 628)

text: is the brightest galaxy within the group.  Other members include the

text: peculiar

text: spiral galaxy

text: NGC 660

text: and several smaller irregular galaxies.

text: Cluster galaxy "blueness" may, under certain circumstances, be used as an indicator of ongoing star formation.  Astronomers have identified three spectral classes in which a significant set of blue galaxy cluster members may be categorized.  The first is objects undergoing vigorous star formation with very blue colors and spectra showing emission-filled H-delta lines.  Secondly, post-starburst galaxies are also observed.  These are cluster members showing similarly blue colors as starburst galaxies only with moderate to strong H-delta absorption.  Third are cluster members showing broad and/or high excitation line spectra, often found in active galactic nuclei.  The Butcher–Oemler observations suggest at intermediate redshift a higher rate of star formation may be observed in a fraction of the galaxies in the cores of rich clusters than in the cores of rich clusters at low redshift.

text: Cluster galaxy "blueness" may, under certain circumstances, be used as an indicator of ongoing

text: star formation

text: .  Astronomers have identified three spectral classes in which a significant set of blue galaxy cluster members may be categorized.  The first is objects undergoing vigorous star formation with very blue colors and spectra showing emission-filled

text: H-delta

text: lines.  Secondly, post-starburst galaxies are also observed.  These are cluster members showing similarly blue colors as

text: starburst galaxies

text: only with moderate to strong H-delta absorption.  Third are cluster members showing broad and/or high excitation line spectra, often found in

text: active galactic nuclei

text: .  The Butcher–Oemler observations suggest at intermediate redshift a higher rate of star formation may be observed in a fraction of the galaxies in the cores of rich clusters than in the cores of rich clusters at low redshift.

text: The collaboration sought answers to the differences in the origins of the various galaxy types — elliptical, lenticular, and spiral. The studies found that elliptical galaxies were the oldest and formed from the violent merger of other galaxies about two to three billion years after the Big Bang. Star formation in elliptical galaxies ceased about that time. On the other hand, new stars are still forming in the spiral arms of spiral galaxies. Lenticular galaxies (SO) are intermediate between the first two.  They contain structures similar to spiral arms, but devoid of the gas and new stars of the spiral galaxies. Lenticular galaxies are the prevalent form in rich galaxy clusters, which suggests that spirals may be transformed into lenticular galaxies as time progresses.  The exact process may be related to high galactic density, or to the total mass in a rich cluster’s central core. The Morphs collaboration found that one of the principal mechanisms of this transformation involves the interaction among spiral galaxies, as they fall toward the core of the cluster.

text: The collaboration sought answers to the differences in the origins of the various galaxy types —

text: elliptical

text: lenticular

text: , and

text: spiral

text: . The studies found that elliptical galaxies were the oldest and formed from the violent merger of other galaxies about two to three billion years after the

text: Big Bang

text: . Star formation in elliptical galaxies ceased about that time. On the other hand, new stars are still forming in the spiral arms of spiral galaxies. Lenticular galaxies (SO) are intermediate between the first two.  They contain structures similar to spiral arms, but devoid of the gas and new stars of the spiral galaxies. Lenticular galaxies are the prevalent form in rich galaxy clusters, which suggests that spirals may be transformed into lenticular galaxies as time progresses.  The exact process may be related to high galactic density, or to the total mass in a rich cluster’s central core. The Morphs collaboration found that one of the principal mechanisms of this transformation involves the interaction among spiral galaxies, as they fall toward the core of the cluster.

text: NGC 4485 is an irregular galaxy located in the constellation of Canes Venatici. It interacts with the spiral galaxy NGC 4490 and as a reasult both galaxies are distorted and show star formation.

text: NGC 4485 is an

text: irregular galaxy

text: located in the constellation of

text: Canes Venatici

text: . It interacts with the spiral galaxy

text: NGC 4490

text: and as a reasult both galaxies are distorted and show star formation.

text: A starburst galaxy is a galaxy undergoing an exceptionally high rate of star formation, as compared to the long-term average rate of star formation in the galaxy or the star formation rate observed in most other galaxies. In a starburst galaxy, the rate of star formation is so large that the galaxy will consume all of its gas reservoir, from which the stars are forming, on a timescale much shorter than the age of the galaxy. As such, the starburst nature of a galaxy is a phase, and one that typically occupies a brief period of a galaxy's evolution. The majority of starburst galaxies are in the midst of a merger or close encounter with another galaxy.  Starburst galaxies include M82, NGC 4038/NGC 4039 (the Antennae Galaxies), and IC 10.

text: A starburst galaxy is a

text: galaxy

text: undergoing an exceptionally high rate of

text: star formation

text: , as compared to the long-term average rate of star formation in the galaxy or the star formation rate observed in most other galaxies. In a starburst galaxy, the rate of star formation is so large that the galaxy will consume all of its gas reservoir, from which the stars are forming, on a timescale much shorter than the age of the galaxy. As such, the

text: starburst

text: nature of a galaxy is a phase, and one that typically occupies a brief period of a

text: galaxy's evolution

text: . The majority of starburst galaxies are in the midst of a

text: merger

text: or close encounter with another galaxy.  Starburst galaxies include

text: NGC 4038/NGC 4039

text: (the Antennae Galaxies), and

text: IC 10

text: Discoveries in the early 21st century have added dimension to the knowledge of the Milky Way's structure. With the discovery that the disk of the Andromeda Galaxy (M31) extends much further than previously thought, the possibility of the disk of the Milky Way extending further is apparent, and this is supported by evidence from the discovery of the Outer Arm extension of the Cygnus Arm and of a similar extension of the Scutum-Centaurus Arm. With the discovery of the Sagittarius Dwarf Elliptical Galaxy came the discovery of a ribbon of galactic debris as the polar orbit of the dwarf and its interaction with the Milky Way tears it apart. Similarly, with the discovery of the Canis Major Dwarf Galaxy, it was found that a ring of galactic debris from its interaction with the Milky Way encircles the Galactic disk.

text: Discoveries in the early 21st century have added dimension to the knowledge of the Milky Way's structure. With the discovery that the disk of the Andromeda Galaxy (M31) extends much further than previously thought, the possibility of the disk of the Milky Way extending further is apparent, and this is supported by evidence from the discovery of the Outer Arm extension of the

text: Cygnus Arm

text: and of a similar extension of the

text: Scutum-Centaurus Arm

text: . With the discovery of the

text: Sagittarius Dwarf Elliptical Galaxy

text: came the discovery of a ribbon of galactic debris as the polar orbit of the dwarf and its interaction with the Milky Way tears it apart. Similarly, with the discovery of the

text: Canis Major Dwarf Galaxy

text: , it was found that a ring of galactic debris from its interaction with the Milky Way encircles the Galactic disk.

text: The sound of each individual's voice is entirely unique not only because of the actual shape and size of an individual's vocal cords but also due to the size and shape of the rest of that person's body, especially the vocal tract, and the manner in which the speech sounds are habitually formed and articulated. (It is this latter aspect of the sound of the voice that can be mimicked by skilled performers.) Humans have vocal folds that can loosen, tighten, or change their thickness, and over which breath can be transferred at varying pressures. The shape of chest and neck, the position of the tongue, and the tightness of otherwise unrelated muscles can be altered. Any one of these actions results in a change in pitch, volume, timbre, or tone of the sound produced. Sound also resonates within different parts of the body, and an individual's size and bone structure can affect somewhat the sound produced by an individual.

text: A galaxy is a large gravitational aggregation of stars, dust,  gas, and an unknown component termed dark matter. The Milky Way Galaxy is only one of billions of galaxies in the known universe. Galaxies are classified into spirals, ellipticals, irregular, and peculiar. Sizes can range from only a few thousand stars (dwarf irregulars) to 10 stars in giant ellipticals. Elliptical galaxies are spherical or elliptical in appearance. Spiral galaxies range from S0, the lenticular galaxies, to Sb, which have a bar across the nucleus, to Sc galaxies which have strong spiral arms.  In total count, ellipticals amount to 13%, S0 to 22%, Sa, b, c galaxies to 61%, irregulars to 3.5% and peculiars to 0.9%.

text: A

text: galaxy

text: is a large gravitational aggregation of stars, dust,  gas, and an unknown component termed

text: dark matter

text: . The

text: Milky Way Galaxy

text: is only one of billions of galaxies in the known universe. Galaxies are classified into

text: spiral

text: s,

text: elliptical

text: s,

text: irregular

text: , and

text: peculiar

text: . Sizes can range from only a few thousand stars (dwarf irregulars) to 10 stars in giant ellipticals. Elliptical galaxies are spherical or elliptical in appearance. Spiral galaxies range from S0, the lenticular galaxies, to Sb, which have a bar across the nucleus, to Sc galaxies which have strong spiral arms.  In total count, ellipticals amount to 13%, S0 to 22%, Sa, b, c galaxies to 61%, irregulars to 3.5% and peculiars to 0.9%.

text: An anemic galaxy's most probable fate is to lose their remaining gas and star formation, becoming similar to a lenticular galaxy: it therefore is likely that most lenticular galaxies in clusters, are former spiral galaxies.

text: Knowledge of Earth's location in the Universe has been shaped by 400 years of telescopic observations, and has expanded radically in the last century. Initially, Earth was believed to be the center of the Universe,  which consisted only of those planets visible with the naked eye and an outlying sphere of fixed stars. After the acceptance of the heliocentric model in the 17th century, observations by William Herschel and others showed that the Sun lay within a vast, disc-shaped galaxy of stars. By the 20th century, observations of spiral nebulae revealed that our galaxy was one of billions in an expanding universe, grouped into clusters and superclusters. By the end of the 20th century, the overall structure of the visible universe was becoming clearer, with superclusters forming into a vast web of filaments and voids. Superclusters, filaments and voids are the largest coherent structures in the Universe that we can observe. At still larger scales (over 1000 megaparsecs) the Universe becomes homogeneous meaning that all its parts have on average the same density, composition and structure.

text: Knowledge of Earth's location in the Universe has been shaped by 400 years of telescopic observations, and has expanded radically in the last century. Initially, Earth was believed to be the

text: center of the Universe

text: ,  which consisted only of those planets visible with the

text: naked eye

text: and an outlying sphere of

text: fixed stars

text: . After the acceptance of the

text: heliocentric model

text: in the 17th century, observations by

text: William Herschel

text: and others showed that the Sun lay within a vast, disc-shaped

text: galaxy

text: of stars. By the 20th century, observations of

text: spiral nebula

text: e revealed that our galaxy was one of billions in an

text: expanding universe

text: , grouped into clusters and

text: supercluster

text: s. By the end of the 20th century, the

text: overall structure

text: of the visible universe was becoming clearer, with superclusters forming into a vast web of

text: filaments

text: and

text: voids

text: . Superclusters, filaments and voids are the largest coherent structures in the Universe that we can observe. At still larger scales (over 1000

text: megaparsec

text: s) the Universe becomes homogeneous meaning that all its parts have on average the same density, composition and structure.

text: Short term neural adaptations occur in the body during rhythmic activities. One of the most common activities when these neural adaptations are constantly happening is walking. As a person walks, the body constantly gathers information about the environment and the surroundings of the feet, and slightly adjusts the muscles in use according to the terrain. For example, walking uphill requires different muscles than walking on flat pavement. When the brain recognizes that the body is walking uphill, it makes neural adaptations that send more activity to muscles required for uphill walking.The rate of neural adaptation is affected by the area of the brain and by the similarity between sizes and shapes of previous stimuli. Adaptations in the inferior temporal gyrus are very dependent on previous stimuli being of similar size, and somewhat dependent on previous stimuli being of a similar shape. Adaptations in the Prefrontal Cortex are less dependent on previous stimuli being of similar size and shape.

text: Short term neural adaptations occur in the body during

text: rhythmic

text: activities. One of the most common activities when these neural adaptations are constantly happening is walking. As a person walks, the body constantly gathers information about the environment and the surroundings of the feet, and slightly adjusts the muscles in use according to the

text: terrain

text: . For example, walking uphill requires different muscles than walking on flat pavement. When the brain recognizes that the body is walking uphill, it makes neural adaptations that send more activity to muscles required for uphill walking.The rate of neural adaptation is affected by the area of the brain and by the similarity between sizes and shapes of previous stimuli. Adaptations in the

text: inferior temporal gyrus

text: are very dependent on previous stimuli being of similar size, and somewhat dependent on previous stimuli being of a similar shape. Adaptations in the

text: Prefrontal Cortex

text: are less dependent on previous stimuli being of similar size and shape.

text: The original paper describing VIRGOHI21 as a dark galaxy provides several objections to the tidal-tail interpretation: that high-velocity interactions do not generally produce significant tails, that the high velocity needed is out-of-place in this part of the Virgo cluster and that the observed velocity profile is opposite from that expected in a tidal tail. In addition, according to Robert Minchin of the Arecibo Observatory, "If the hydrogen in VIRGOHI21 had been pulled out of a nearby galaxy, the same interaction should have pulled out stars as well". Proponents of the tidal-tail interpretation counter these objections with simulations and argue that the apparently inverted velocity profile is due to the orientation of the tail with respect to Earth-based observers.

text: It is widely accepted that the main driving force for the evolution of elliptical galaxies is mergers of smaller galaxies. Many galaxies in the universe are gravitationally bound to other galaxies, which means that they will never escape the pull of the other galaxy. If the galaxies are of similar size, the resultant galaxy will appear similar to neither of the two galaxies merging, but will instead be an elliptical galaxy.

text: It is widely accepted that the main driving force for the evolution of elliptical galaxies is

text: mergers

text: of smaller galaxies. Many galaxies in the universe are gravitationally bound to other galaxies, which means that they will never escape the pull of the other galaxy. If the galaxies are of similar size, the resultant galaxy will appear similar to neither of the two galaxies merging, but will instead be an elliptical galaxy.

text: NGC 6362 is a globular cluster in the constellation Ara, lying close to Apus in the southern sky. A telescope with a 150mm primary mirror is required to resolve the stars within this irregularly shaped cluster. The cluster NGC 6362, what's known as a globular cluster, was observed by the Wide Field Imager attached to the MPG/ESO 2.2-meter telescope at ESO's La Silla Observatory in Chile. The resulting photo shows tens of thousands of very ancient stars, along with a good amount of stars passing off younger than they actually are. Tightly bound by gravity, globular clusters are composed of old stars, which, are around 10 billion years old, and much older than the sun. These clusters are fairly common. there are more than 150 currently known in our galaxy, the Milky Way, and more which have been spotted in other galaxies. All stars are usually around the same age in a given cluster. Most of the stars inside the cluster are thought to have formed at or around the same time and are thought to be of similar age. Most of the stars inside NGC 6362 are red giants that appear yellow and aged, however, you also see a number of so-called blue stragglers, stars that appear younger than their true age. Blue stars are hot and consume their fuel quickly.

text: NGC 6362 is a

text: globular cluster

text: in the

text: constellation

text: Ara

text: , lying close to

text: Apus

text: in the southern sky. A

text: telescope

text: ULAS J0015+01 is, at the current time, 900,000 light years away from the Milky Way galaxy. The Milky Way's disk is 180,000 light years in diameter, putting it far beyond the Milky Way stellar disk, or only 3 times closer than the Andromeda galaxy. In comparison, in distance to the Milky Way's satellite galaxy, the Large Magellanic Cloud, is only 160,000 light-years from Earth. ULAS J0015+01 and ULAS J0744+25 are not technically in a galaxy, but they are both classified as being in the Milky Way's outer halo, which stretches at least 500,000 light years away. These stars were both the first to be discovered beyond 200 kpc.

text: ULAS J0015+01 is, at the current time, 900,000 light years away from the Milky Way galaxy. The Milky Way's disk is 180,000 light years in diameter, putting it far beyond the Milky Way stellar disk, or only 3 times closer than the

text: Andromeda

text: galaxy. In comparison, in distance to the Milky Way's satellite galaxy, the

text: Large Magellanic Cloud

text: , is only 160,000 light-years from Earth. ULAS J0015+01 and ULAS J0744+25 are not technically in a galaxy, but they are both classified as being in the Milky Way's outer halo, which stretches at least 500,000 light years away. These stars were both the first to be discovered beyond 200

text: kpc

text: The Galaxy Zoo forum became a hotbed for the discussion of the SDSS images and more general science questions. Its 'global moderator', UK teacher Alice Sheppard, said of it: "I don't quite know what it is, but Galaxy Zoo does something to people. The contributions, both creative and academic, that people have made to the forum are as stunning as the sight of any spiral, and never fail to move me." Author Michael Nielsen wrote in his book Reinventing Discovery: "But Galaxy Zoo can go beyond computers, because it can also apply human intelligence in the analysis, the kind of intelligence that recognizes that Hanny's Voorwerp or a Pea galaxy is out of the ordinary, and deserves further investigation. Galaxy Zoo is thus a hybrid, able to do deep analyses of large data sets that are impossible in any other way." A community feeling was also created. Roger Davies stated: "The community of Galaxy Zoo gives them the opportunity to participate that they’re looking for.” This community became known as the 'Zooites'. Aida Berges, a homemaker living in Puerto Rico who has classified hundreds of thousands of galaxies, stated: "Every galaxy has a story to tell. They are beautiful, mysterious, and show how amazing our universe is. It was love at first sight when I started in Galaxy Zoo ... It is a magical place, and it feels like coming home at last." The Galaxy Zoo Forum became a read-only archive in July 2014. After seven years online and over 650,000 posts, it continues to generate science.

text: The Galaxy Zoo forum became a hotbed for the discussion of the SDSS images and more general science questions. Its 'global moderator',

text: UK

text: teacher Alice Sheppard, said of it: "I don't quite know what it is, but Galaxy Zoo does something to people. The contributions, both creative and academic, that people have made to the forum are as stunning as the sight of any spiral, and never fail to move me." Author

text: Michael Nielsen

text: wrote in his book

text: Reinventing Discovery

text: : "But Galaxy Zoo can go beyond computers, because it can also apply human intelligence in the analysis, the kind of intelligence that recognizes that Hanny's Voorwerp or a Pea galaxy is out of the ordinary, and deserves further investigation. Galaxy Zoo is thus a hybrid, able to do deep analyses of large data sets that are impossible in any other way." A

text: community

text: feeling was also created. Roger Davies stated: "The community of Galaxy Zoo gives them the opportunity to participate that they’re looking for.” This community became known as the 'Zooites'. Aida Berges, a homemaker living in

text: Puerto Rico

text: who has classified hundreds of thousands of galaxies, stated: "Every galaxy has a story to tell. They are beautiful, mysterious, and show how amazing our

text: universe

text: is. It was love at first sight when I started in Galaxy Zoo ... It is a magical place, and it feels like coming home at last." The Galaxy Zoo Forum became a read-only

text: archive

text: in July 2014. After seven years online and over 650,000 posts, it continues to generate science.

text: Body shapes are often categorised in the fashion industry into one of four elementary geometric shapes, though there are very wide ranges of actual sizes within each shape:

text: Galaxy was a radio network owned by Global Radio and broadcast across the British Isles on FM in regional areas of England and Scotland, through the digital platform with Sky and DAB and online respectively. Stations included stations: Galaxy Birmingham, Galaxy Manchester, Galaxy North East, Galaxy Scotland, Galaxy South Coast and Galaxy Yorkshire. Programming was networked throughout the stations from Leeds - excluding weekday breakfast/drivetime and weekend mornings. On Monday 28 April 2008, Galaxy was rebranded as a mainstream station by Creative Spark with a brand new layout including a fresh logo and a completely new show schedule.

text: Galaxy was a radio network owned by

text: Global Radio

text: and broadcast across the British Isles on FM in regional areas of

text: England

text: and

text: Scotland

text: , through the digital platform with Sky and DAB and online respectively. Stations included stations:

text: Galaxy Birmingham

text: Galaxy Manchester

text: Galaxy North East

text: Galaxy Scotland

text: Galaxy South Coast

text: and

text: Galaxy Yorkshire

text: . Programming was networked throughout the stations from

text: Leeds

text: - excluding weekday breakfast/drivetime and weekend mornings. On Monday 28 April 2008, Galaxy was rebranded as a mainstream station by Creative Spark with a brand new layout including a fresh logo and a completely new show schedule.

text: In 2011 NASA's Jet Propulsion Laboratory (JPL) and based on observations from the Kepler Mission is that about 1.4% to 2.7% of all Sun-like stars are expected to have Earth-size planets within the habitable zones of their stars. This means there could be two billion of them in the Milky Way galaxy alone, and assuming that all galaxies have a similar number as the Milky Way, in the 50 billion galaxies in the observable universe, there may be as many as a hundred quintillion.

text: In 2011 NASA's

text: Jet Propulsion Laboratory

text: (JPL) and based on observations from the Kepler Mission is that about 1.4% to 2.7% of all Sun-like

text: star

text: s are expected to have Earth-size planets within the

text: habitable zone

text: s of their stars. This means there could be two billion of them in the Milky Way galaxy alone, and assuming that all galaxies have a similar number as the Milky Way, in the 50 billion galaxies in the

text: observable universe

text: , there may be as many as a hundred

text: quintillion

text: The two galaxies in Arp 272 are in physical contact through their spiral arms. A third galaxy can be seen at the top of them.

text: The two galaxies in Arp 272 are in physical contact through their

text: spiral arm

text: s. A third galaxy can be seen at the top of them.

text: Detailed observations of the morphology and distribution of galaxies and quasars are in agreement with the current state of the Big Bang theory. A combination of observations and theory suggest that the first quasars and galaxies formed about a billion years after the Big Bang, and since then larger structures have been forming, such as galaxy clusters and superclusters. Populations of stars have been aging and evolving, so that distant galaxies (which are observed as they were in the early universe) appear very different from nearby galaxies (observed in a more recent state). Moreover, galaxies that formed relatively recently appear markedly different from galaxies formed at similar distances but shortly after the Big Bang. These observations are strong arguments against the steady-state model. Observations of star formation, galaxy and quasar distributions and larger structures agree well with Big Bang simulations of the formation of structure in the universe and are helping to complete details of the theory.

text: Detailed observations of the

text: morphology

text: and

text: distribution

text: of galaxies and

text: quasars

text: are in agreement with the current state of the Big Bang theory. A combination of observations and theory suggest that the first quasars and galaxies formed about a billion years after the Big Bang, and since then larger structures have been forming, such as

text: galaxy clusters

text: and

text: supercluster

text: s. Populations of stars have been aging and evolving, so that distant galaxies (which are observed as they were in the early universe) appear very different from nearby galaxies (observed in a more recent state). Moreover, galaxies that formed relatively recently appear markedly different from galaxies formed at similar distances but shortly after the Big Bang. These observations are strong arguments against the steady-state model. Observations of

text: star formation

text: , galaxy and quasar distributions and larger structures agree well with Big Bang simulations of the formation of structure in the universe and are helping to complete details of the theory.

text: NGC 2903 is a barred spiral galaxy discovered by William Herschel in 1784. It is very similar in size and shape to the Milky Way and is located 25 million light-years from Earth. In its core, NGC 2903 has many "hotspots", which have been found to be near regions of star formation. The star formation in this region is thought to be due to the presence of the dusty bar, which sends shock waves through its rotation to an area with a diameter of 2,000 light-years. The outskirts of the galaxy have many young open clusters.

text: NGC 2903

text: is a

text: barred spiral galaxy

text: discovered by

text: William Herschel

text: in 1784. It is very similar in size and shape to the Milky Way and is located 25 million light-years from Earth. In its core, NGC 2903 has many "hotspots", which have been found to be near regions of

text: star formation

text: . The star formation in this region is thought to be due to the presence of the dusty bar, which sends shock waves through its rotation to an area with a diameter of 2,000 light-years. The outskirts of the galaxy have many young

text: open cluster

text: s.

text: The Wolf–Lundmark–Melotte (WLM) is an irregular galaxy discovered in 1909 by Max Wolf,  located on the outer edges of the Local Group. The discovery of the nature of the galaxy was accredited to Knut Lundmark and Philibert Jacques Melotte in 1926.  It is in the constellation Cetus.

text: The Wolf–Lundmark–Melotte (WLM) is an

text: irregular galaxy

text: discovered in 1909 by

text: Max Wolf

text: ,  located on the outer edges of the

text: Local Group

text: . The discovery of the nature of the galaxy was accredited to

text: Knut Lundmark

text: and

text: Philibert Jacques Melotte

text: in 1926.  It is in the

text: constellation

text: Cetus

text: Since the 1960s, there have been two leading hypotheses or models for the spiral structures of galaxies:

text: Self-replicating probes could exhaustively explore a galaxy the size of the Milky Way in as little as a million years. If even a single civilization in the Milky Way attempted this, such probes could spread throughout the entire galaxy. Another speculation for contact with an alien probe—one that would be trying to find human beings—is an alien Bracewell probe. Such a hypothetical device would be an autonomous space probe whose purpose is to seek out and communicate with alien civilizations (as opposed to Von Neumann probes, which are usually described as purely exploratory). These were proposed as an alternative to carrying a slow speed-of-light dialogue between vastly distant neighbors. Rather than contending with the long delays a radio dialogue would suffer, a probe housing an artificial intelligence would seek out an alien civilization to carry on a close-range communication with the discovered civilization. The findings of such a probe would still have to be transmitted to the home civilization at light speed, but an information-gathering dialogue could be conducted in real time.

text: Self-replicating probes could exhaustively explore a galaxy the size of the

text: Milky Way

text: in as little as a million years. If even a single civilization in the Milky Way attempted this, such probes could spread throughout the entire galaxy. Another speculation for contact with an alien probe—one that would be trying to find human beings—is an alien

text: Bracewell probe

text: . Such a hypothetical device would be an autonomous space probe whose purpose is to seek out and communicate with alien civilizations (as opposed to Von Neumann probes, which are usually described as purely exploratory). These were proposed as an alternative to carrying a slow

text: speed-of-light

text: dialogue between vastly distant neighbors. Rather than contending with the long delays a radio dialogue would suffer, a probe housing an

text: artificial intelligence

text: would seek out an alien civilization to carry on a close-range communication with the discovered civilization. The findings of such a probe would still have to be transmitted to the home civilization at light speed, but an information-gathering dialogue could be conducted in real time.

text: This page lists some galaxy groups and galaxy clusters.

text: This page lists some

text: galaxy group

text: s and

text: galaxy cluster

text: s.

text: The constituents of a galaxy are formed out of gaseous matter that assembles through gravitational self-attraction in a hierarchical manner. At this level, the resulting fundamental components are the stars, which are typically assembled in clusters from the various condensing nebulae. The great variety of stellar forms are determined almost entirely by the mass, composition and evolutionary state of these stars. Stars may be found in multi-star systems that orbit about each other in a hierarchical organization. A planetary system and various minor objects such as asteroids, comets and debris, can form in a hierarchical process of accretion from the protoplanetary disks that surrounds newly formed stars.

text: The constituents of a galaxy are formed out of gaseous matter that assembles through gravitational self-attraction in a hierarchical manner. At this level, the resulting fundamental components are the stars, which are typically assembled in clusters from the various condensing nebulae. The great variety of stellar forms are determined almost entirely by the mass, composition and evolutionary state of these stars. Stars may be found in multi-star systems that orbit about each other in a hierarchical organization. A planetary system and various minor objects such as asteroids, comets and debris, can form in a hierarchical process of accretion from the

text: protoplanetary disk

text: s that surrounds newly formed stars.

text: The term "protogalaxy" itself is generally accepted to mean "Progenitors of the present day (normal) galaxies, in the early stages of formation." However, the "early stages of formation" is not a clearly defined phrase. It could be defined as: "The first major burst of star formation in a progenitor of a present day elliptical galaxy"; "The peak merging epoch of dark halos of the fragments which assemble to produce an average galaxy today"; "A still gaseous body before any star formation has taken place."; or " an over-dense region of dark matter in the very early universe, destined to become gravitationally bound and to collapse."

text: The term "protogalaxy" itself is generally accepted to mean "Progenitors of the present day (normal) galaxies, in the early stages of formation." However, the "early stages of formation" is not a clearly defined phrase. It could be defined as: "The first major burst of

text: star formation

text: in a progenitor of a present day elliptical galaxy"; "The peak merging

text: epoch

text: of

text: dark halo

text: s of the fragments which assemble to produce an average galaxy today"; "A still gaseous body before any star formation has taken place."; or " an over-dense region of

text: dark matter

text: in the very

text: early universe

text: , destined to become

text: gravitationally bound

text: and to collapse."

text: Due to the work of Edwin Hubble, it is now known that the Milky Way is only one of as many as an estimated 200 billion galaxies in the observable universe, proving Curtis the more accurate party in the debate. Also, astronomers generally accept that the nova Shapley referred to in his arguments was in fact a supernova, which do indeed temporarily outshine the combined output of an entire galaxy. On other points the results were mixed (the actual size of the Milky Way is in between the sizes proposed by Shapley and Curtis), or in favor of Shapley (Curtis' galaxy was centered on the Sun, while Shapley correctly placed the Sun in the outer regions of the galaxy).

text: Due to the work of

text: Edwin Hubble

text: , it is now known that the Milky Way is only one of as many as an estimated 200 billion galaxies in the

text: observable universe

text: , proving Curtis the more accurate party in the debate. Also, astronomers generally accept that the nova Shapley referred to in his arguments was in fact a

text: supernova

text: , which do indeed temporarily outshine the combined output of an entire galaxy. On other points the results were mixed (the actual size of the Milky Way is in between the sizes proposed by Shapley and Curtis), or in favor of Shapley (Curtis' galaxy was centered on the Sun, while Shapley correctly placed the Sun in the outer regions of the galaxy).

text: BL Lacertae  or BL Lac is a highly variable, extragalactic AGN (active galactic nucleus or active galaxy). It was first discovered by Cuno Hoffmeister in 1929, but was originally thought to be an irregular variable star in the Milky Way galaxy and so was given a variable star designation. In 1968, the "star" was identified by John Schmitt at the David Dunlap Observatory as a bright, variable radio source. A faint trace of a host galaxy was also found. In 1974, Oke and Gunn measured the redshift of BL Lacertae as z = 0.07, corresponding to a recession velocity of 21,000 km/s with respect to the Milky Way. The redshift figure implies that the object lies at a distance of 900 million light years.

text: BL Lacertae  or BL Lac is a highly variable, extragalactic AGN (active galactic nucleus or

text: active galaxy

text: ). It was first discovered by

text: Cuno Hoffmeister

text: in 1929, but was originally thought to be an irregular

text: variable star

text: in the

text: Milky Way

text: galaxy and so was given a

text: variable star designation

text: . In 1968, the "star" was identified by John Schmitt at the

text: David Dunlap Observatory

text: as a bright, variable

text: radio source

text: . A faint trace of a host

text: galaxy

text: was also found. In 1974, Oke and

text: Gunn

text: measured the

text: redshift

text: of BL Lacertae as z = 0.07, corresponding to a recession velocity of 21,000 km/s with respect to the Milky Way. The redshift figure implies that the object lies at a distance of 900 million light years.

text: Other astronomers have noted that the reddening across the face of this cluster is likely to be uneven. The visibility of several background galaxies in the NW corner of the cluster indicate that the obscuring medium may be lowest here.

text: Other astronomers have noted that the

text: reddening

text: across the face of this cluster is likely to be uneven. The visibility of several background

text: galaxies

text: in the NW corner of the cluster indicate that the obscuring medium may be lowest here.

text: NGC 1427A is an irregular galaxy in the constellation Eridanus.  Its distance modulus has been estimated using the globular cluster luminosity function to be 31.01 ± 0.21 which is about 52 Mly.  It is the brightest dwarf irregular member of the Fornax cluster and is in the foreground of the cluster's central galaxy NGC 1399.

text: NGC 1427A is an

text: irregular galaxy

text: in the

text: constellation

text: Eridanus

text: .  Its

text: distance modulus

text: has been estimated using the

text: globular cluster luminosity function

text: to be 31.01 ± 0.21 which is about 52 Mly.  It is the brightest dwarf irregular member of the

text: Fornax cluster

text: and is in the foreground of the cluster's central galaxy

text: NGC 1399

text: Arp thought that the elliptical galaxies in this category were ejecting material from their nuclei.  Many of the pictures could be interpreted that way. However, these objects are actually a mixture of other phenomena. For example, NGC 2914 (Arp 137) is merely a spiral galaxy with faint spiral arms, and NGC 4015 (Arp 138) is an interacting pair of galaxies where one galaxy is an edge-on spiral galaxy. Some objects, such as NGC 2444 and NGC 2445 (Arp 143), are systems that contain "ring galaxies", which are created when one galaxy (the elliptical galaxies in these examples) passes through the disk of another. This passage causes a gravitational wave in which gas first falls inward and then propagates outward to form the ring structure.

text: Arp thought that the elliptical galaxies in this category were ejecting material from their nuclei.  Many of the pictures could be interpreted that way. However, these objects are actually a mixture of other phenomena. For example,

text: NGC 2914

text: (Arp 137) is merely a spiral galaxy with faint spiral arms, and

text: NGC 4015

text: (Arp 138) is an interacting pair of galaxies where one galaxy is an edge-on spiral galaxy. Some objects, such as

text: NGC 2444

text: and

text: NGC 2445

text: Arp 143

text: ), are systems that contain "ring galaxies", which are created when one galaxy (the elliptical galaxies in these examples) passes through the disk of another. This passage causes a gravitational wave in which gas first falls inward and then propagates outward to form the ring structure.

text: Shapes and sizes became standardised, the most well-known shape being the "common or garden" trug ranging in volume from one pint to a bushel.  However, there is a diverse range of traditional trugs from garden and oval trugs to the more specialised "large log" and "walking stick" trugs.

text: Shapes and sizes became standardised, the most well-known shape being the "common or garden" trug ranging in volume from

text: one pint to a bushel

text: .  However, there is a diverse range of traditional trugs from garden and oval trugs to the more specialised "large log" and "walking stick" trugs.

text: Galaxies in this category have either irregular structures (irregularities), notable dust lanes (absorption), or a grainy appearance (resolution). This category contains a mix of interacting galaxies distorted by tidal interactions, nearby dwarf irregular galaxies, and spiral galaxies with unusual large amounts of gas.

text: Draco also features several interacting galaxies and galaxy clusters. One such massive cluster is Abell 2218, located at a distance of 3 billion light-years (redshift 0.171). It acts as a gravitational lens for even more distant background galaxies, allowing astronomers to study those galaxies as well as Abell 2218 itself; more specifically, the lensing effect allows astronomers to confirm the cluster's mass as determined by x-ray emissions. One of the most well-known interacting galaxies is Arp 188, also called the "Tadpole Galaxy". Named for its appearance, which features a "tail" of stars 280,000 light-years long, the Tadpole Galaxy is at a distance of 420 million light-years (redshift 0.0314). The tail of stars drawn off the Tadpole Galaxy appears blue because the gravitational interaction disturbed clouds of gas and sparked star formation.

text: Draco also features several

text: interacting galaxies

text: and

text: galaxy cluster

text: s. One such massive cluster is

text: Abell 2218

text: , located at a distance of 3 billion light-years (

text: redshift

text: 0.171). It acts as a

text: gravitational lens

text: for even more distant background galaxies, allowing astronomers to study those galaxies as well as Abell 2218 itself; more specifically, the lensing effect allows astronomers to confirm the cluster's mass as determined by

text: x-ray

text: emissions. One of the most well-known

text: interacting galaxies

text: is

text: Arp 188

text: , also called the "Tadpole Galaxy". Named for its appearance, which features a "tail" of stars 280,000 light-years long, the Tadpole Galaxy is at a distance of 420 million light-years (redshift 0.0314). The tail of stars drawn off the Tadpole Galaxy appears blue because the gravitational interaction disturbed

text: clouds of gas

text: and sparked

text: star formation

text: NGC 4980 is a spiral galaxy in the southern constellation of Hydra. The shape of NGC 4980 appears slightly deformed, something which is often a sign of recent tidal interactions with another galaxy. In this galaxy’s case, however, this appears not to be the case as there are no other galaxies in its immediate vicinity.

text: NGC 4980 is a

text: spiral galaxy

text: in the southern constellation of

text: Hydra

text: . The shape of NGC 4980 appears slightly deformed, something which is often a sign of recent tidal interactions with another galaxy. In this galaxy’s case, however, this appears not to be the case as there are no other galaxies in its immediate vicinity.

text: Recent results suggest that the orientation of the spin axis of spiral galaxies is not a chance result, but instead they are preferentially aligned along the surface of cosmic voids. That is, spiral galaxies tend to be oriented at a high angle of inclination relative to the large-scale structure of the surroundings. They have been described as lining up like "beads on a string," with their axis of rotation following the filaments around the edges of the voids.

text: Recent results suggest that the orientation of the spin axis of spiral galaxies is not a chance result, but instead they are preferentially aligned along the surface of

text: cosmic voids

text: . That is, spiral galaxies tend to be oriented at a high angle of inclination relative to the large-scale structure of the surroundings. They have been described as lining up like "beads on a string," with their axis of rotation following the

text: filaments

text: around the edges of the voids.

text: NGC 5257 is a spiral galaxy located in the constellation Virgo.  The galaxy is notably interacting with the spiral galaxy NGC 5258.  The two galaxies are listed together as Arp 240 in the Atlas of Peculiar Galaxies.  Both galaxies are distorted by the gravitational interaction, and both are connected by a tidal bridge, as can be seen in images of these galaxies.

text: NGC 5257 is a

text: spiral galaxy

text: located in the

text: constellation

text: Virgo

text: .  The galaxy is notably

text: interacting

text: with the spiral galaxy

text: NGC 5258

text: .  The two galaxies are listed together as

text: Arp 240

text: in the

text: Atlas of Peculiar Galaxies

text: .  Both galaxies are distorted by the gravitational interaction, and both are connected by a tidal bridge, as can be seen in images of these galaxies.

text: Elliptical galaxies are characterized by several properties that make them distinct from other classes of galaxy.   They are spherical or ovoid masses of stars, starved of star-making gases. The smallest known elliptical galaxy is about one-tenth the size of the Milky Way. The motion of stars in elliptical galaxies is predominantly radial, unlike the disks of spiral galaxies, which are dominated by rotation. Furthermore, there is very little interstellar matter (neither gas nor dust), which results in low rates of star formation, few open star clusters, and few young stars; rather elliptical galaxies are dominated by old stellar populations, giving them red colors. Large elliptical galaxies typically have an extensive system of globular clusters.

text: Elliptical galaxies are characterized by several properties that make them distinct from other classes of galaxy.   They are spherical or ovoid masses of stars, starved of star-making gases. The smallest known elliptical galaxy is about one-tenth the size of the

text: Milky Way

text: . The motion of stars in elliptical galaxies is predominantly radial, unlike the disks of

text: spiral galaxies

text: , which are dominated by

text: rotation

text: . Furthermore, there is very little

text: interstellar matter

text: (neither gas nor dust), which results in low rates of

text: star formation

text: , few

text: open star clusters

text: , and few young stars; rather elliptical galaxies are dominated by

text: old stellar populations

text: , giving them red colors. Large elliptical galaxies typically have an extensive system of

text: globular cluster

text: s.

text: NGC 1042 is a spiral galaxy in the ConstellationCetus.

text: NGC 1042 is a

text: spiral galaxy

text: in the

text: Constellation

text: Cetus

text: Wolf–Rayet stars are a normal stage in the evolution of very massive stars, in which strong, broad emission lines of helium and nitrogen ("WN" sequence), carbon ("WC" sequence), and oxygen ("WO" sequence) are visible. Due to their strong emission lines they can be identified in nearby galaxies.  About 500 Wolf–Rayets are catalogued in our own Milky Way Galaxy.  This number has changed dramatically during the last few years as the result of photometric and spectroscopic surveys in the near-infrared dedicated to discovering this kind of object in the Galactic plane.  It is expected that there are fewer than 1,000 WR stars in the rest of the Local Group galaxies, with around 150 known in the Magellanic Clouds, 206 in M33, and 154 in M31.  Outside the local group, whole galaxy surveys have found thousands more WR stars and candidates.  For example, over a thousand WR stars have been detected in M101, from magnitude 21 to 25.  WR stars are expected to be particularly common in starburst galaxies and especially Wolf–Rayet galaxies.

text: Wolf–Rayet stars are a normal stage in the evolution of very massive stars, in which strong, broad

text: emission lines

text: of helium and nitrogen ("WN" sequence), carbon ("WC" sequence), and oxygen ("WO" sequence) are visible. Due to their strong emission lines they can be identified in nearby galaxies.  About 500 Wolf–Rayets are catalogued in our own

text: Milky Way Galaxy

text: .  This number has changed dramatically during the last few years as the result of photometric and spectroscopic surveys in the near-infrared dedicated to discovering this kind of object in the

text: Galactic plane

text: .  It is expected that there are fewer than 1,000 WR stars in the rest of the

text: Local Group

text: galaxies, with around 150 known in the

text: Magellanic Clouds

text: , 206 in

text: , and 154 in

text: .  Outside the local group, whole galaxy surveys have found thousands more WR stars and candidates.  For example, over a thousand WR stars have been detected in M101, from magnitude 21 to 25.  WR stars are expected to be particularly common in

text: starburst galaxies

text: and especially

text: Wolf–Rayet galaxies

text: Star Ruler features a 1 to 10,000+ star system count galaxy of configurable shape.  The size of the in-game universe is only limited by the processing power of the user's computer. Generated systems may have orbiting planets, moons, asteroids, comets, or aggressive, capturable, NPC assets.  Gameplay occurs in a single space in real-time with the rate of time determined by the player. Star Ruler also features Newtonian mechanics in its ship movement.

text: Star Ruler features a 1 to 10,000+ star system count galaxy of configurable shape.  The size of the in-game universe is only limited by the processing power of the user's computer. Generated systems may have orbiting planets, moons, asteroids, comets, or aggressive, capturable, NPC assets.  Gameplay occurs in a single space in real-time with the rate of time determined by the player. Star Ruler also features

text: Newtonian mechanics

text: in its ship movement.

text: A spiral galaxy is a type of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae and, as such, forms part of the Hubble sequence. Spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge. These are surrounded by a much fainter halo of stars, many of which reside in globular clusters.

text: A spiral galaxy is a

text: type

text: of

text: galaxy

text: originally described by

text: Edwin Hubble

text: in his 1936 work

text: The Realm of the Nebulae

text: and, as such, forms part of the

text: Hubble sequence

text: . Spiral galaxies consist of a flat, rotating

text: disk

text: containing

text: star

text: s,

text: gas and dust

text: , and a central concentration of stars known as the

text: bulge

text: . These are surrounded by a much fainter

text: halo

text: of stars, many of which reside in

text: globular cluster

text: s.

text: The origin of the word galaxy derives from the Greek term for the Milky Way,  (γαλαξίας, "milky one"), or  ("milky circle") due to its appearance as a "milky" band of light in the sky. In Greek mythology, Zeus places his son born by a mortal woman, the infant Heracles, on Hera's breast while she is asleep so that the baby will drink her divine milk and will thus become immortal. Hera wakes up while breastfeeding and then realizes she is nursing an unknown baby: she pushes the baby away, some of her milk spills and, produces the faint band of light known as the Milky Way.

text: The origin of the word galaxy derives from the

text: Greek

text: term for the Milky Way,  (γαλαξίας, "milky one"), or  ("milky circle") due to its appearance as a "milky" band of light in the sky. In

text: Greek mythology

text: Zeus

text: places his son born by a mortal woman, the infant

text: Heracles

text: , on

text: Hera

text: 's breast while she is asleep so that the baby will drink her divine milk and will thus become immortal. Hera wakes up while breastfeeding and then realizes she is nursing an unknown baby: she pushes the baby away, some of her milk spills and, produces the faint band of light known as the Milky Way.

text: Approximate logarithmic spirals can occur in nature (for example, the arms of spiral galaxies or phyllotaxis of leaves); golden spirals are one special case of these logarithmic spirals. A recent analysis of spirals observed in mouse corneal epithelial cells indicated that some can be characterized by the golden spiral, and some by other spirals. It is sometimes stated that spiral galaxies and nautilus shells get wider in the pattern of a golden spiral, and hence are related to both  and the Fibonacci series.In truth, spiral galaxies and nautilus shells (and many mollusk shells) exhibit logarithmic spiral growth, but at a variety of angles usually distinctly different from that of the golden spiral.  This pattern allows the organism to grow without changing shape.

text: Approximate

text: logarithmic spiral

text: s can occur in nature (for example, the arms of

text: spiral galaxies

text: or

text: phyllotaxis

text: of leaves); golden spirals are one special case of these logarithmic spirals. A recent analysis of spirals observed in mouse corneal epithelial cells indicated that some can be characterized by the golden spiral, and some by other spirals. It is sometimes stated that spiral galaxies and

text: nautilus

text: shells get wider in the pattern of a golden spiral, and hence are related to both  and the Fibonacci series.In truth, spiral galaxies and nautilus shells (and many

text: mollusk

text: shells) exhibit logarithmic spiral growth, but at a variety of angles usually distinctly different from that of the golden spiral.  This pattern allows the organism to grow without changing shape.

text: Dakara is the planet where the Ancients first landed in the Milky Way Galaxy after fleeing the Alteran Galaxy. It is here where they later built a powerful device, capable of destroying existing life or creating it where there was none before, long before the galaxy was colonized by the Goa'uld or the humans. Long after the Ancients disappeared, the Goa'uld System Lords eventually took possession of the planet, unknowing of its history. The place eventually became a holy ground for their Jaffa servant race since they held legends which described Dakara as the planet where their enslavement began. At the Temple of Dakara, Jaffa were given their strength and longevity through the first implantation of symbiotes. The temple is therefore the ultimate holy ground of the Goa'uld, who kept the Jaffa loyal by propagating lies that they were gods. The idea of stepping into Dakara was unthinkable to the free Jaffa.

text: Dakara is the planet where the

text: Ancients

text: first landed in the Milky Way Galaxy after fleeing the Alteran Galaxy. It is here where they later built a powerful

text: device

text: , capable of destroying existing life or creating it where there was none before, long before the galaxy was colonized by the

text: Goa'uld

text: or the humans. Long after the Ancients disappeared, the Goa'uld System Lords eventually took possession of the planet, unknowing of its history. The place eventually became a holy ground for their Jaffa servant race since they held legends which described Dakara as the planet where their enslavement began. At the Temple of Dakara, Jaffa were given their strength and longevity through the first implantation of symbiotes. The temple is therefore the ultimate holy ground of the Goa'uld, who kept the Jaffa loyal by propagating lies that they were gods. The idea of stepping into Dakara was unthinkable to the free Jaffa.

text: The galaxy is classified as a supergiant elliptical (E) to lenticular (S0) and is the brightest galaxy in A2029 (hence its other designation A2029-BCG; BCG meaning brightest cluster galaxy). The galaxy's morphological type is debated due to it possibly being shaped like a flat disc but only visible from Earth at its broadest dimensions. However, most lenticulars have sizes ranging from .

text: The galaxy is classified as a supergiant elliptical (E) to lenticular (S0) and is the brightest galaxy in A2029 (hence its other designation A2029-BCG; BCG meaning

text: brightest cluster galaxy

text: ). The galaxy's morphological type is debated due to it possibly being shaped like a flat disc but only visible from Earth at its broadest dimensions. However, most lenticulars have sizes ranging from .

text: Lenticular galaxies are unique in that they have a visible disk component as well as a prominent bulge component. They have much higher bulge-to-disk ratios than typical spirals and do not have the canonical spiral arm structure of late-type galaxies, yet may exhibit a central bar. This bulge dominance can be seen in the axis ratio (i.e. the ratio between the observed minor and major axial of a disk galaxy) distribution of a lenticular galaxy sample. The distribution for lenticular galaxies rises steadily in the range 0.25 to 0.85 whereas the distribution for spirals is essentially flat in that same range. Larger axial ratios can be explained by observing face-on disk galaxies or by having a sample of spheroidal (bulge-dominated) galaxies. Imagine looking at two disk galaxies edge-on, one with a bulge and one without a bulge. The galaxy with a prominent bulge will have a larger edge-on axial ratio compared to the galaxy without a bulge based on the definition of axial ratio. Thus a sample of disk galaxies with prominent spheroidal components will have more galaxies at larger axial ratios. The fact that the lenticular galaxy distribution rises with increasing observed axial ratio implies that lenticulars are dominated by a central bulge component.

text: UGC 2140 is an irregular galaxy in the constellation Aries. It was thought to be a compact group of galaxies, catalogued as HCG 18, but in 1999 the object was found to be a single galaxy with multiple star-forming regions.

text: UGC 2140 is an

text: irregular galaxy

text: in the constellation

text: Aries

text: . It was thought to be a

text: compact group

text: of galaxies, catalogued as

text: HCG 18

text: , but in 1999 the object was found to be a single galaxy with multiple

text: star-forming region

text: s.

text: The Leo Cluster (Abell 1367) is a galaxy cluster about 330 million light-years distant (z = 0.022) in the constellation Leo, with at least 70 major galaxies. Along with the Coma Cluster, it is one of the two major clusters comprising the Coma Supercluster. Along with being a part of the Coma Supercluster, that with many others, helps form the Great Wall, which is hundreds of millions years long and is one of the largest structures in the universe. Leo has many galaxies, galaxy clusters and quasars; but lacks nebulae, planetaries, or star clusters.

text: The Leo Cluster (

text: Abell

text: 1367) is a

text: galaxy cluster

text: about 330 million

text: light-year

text: s distant (

text: z

text: = 0.022) in the

text: constellation

text: Leo, with at least 70 major galaxies. Along with the

text: Coma Cluster

text: , it is one of the two major clusters comprising the

text: Coma Supercluster

text: . Along with being a part of the Coma Supercluster, that with many others, helps form the Great Wall, which is hundreds of millions years long and is one of the largest structures in the universe. Leo has many galaxies, galaxy clusters and quasars; but lacks nebulae, planetaries, or star clusters.

text: Vanth Dreadstar first appeared in "The Metamorphosis Odyssey", in Epic Illustrated #3. In the story, where Dreadstar is not the main character, he unwittingly aids the Orsirosian named Akhnaton in destroying the Milky Way Galaxy, the only way to stop the ever-expanding Zygotean empire.

text: Vanth Dreadstar first appeared in "The Metamorphosis Odyssey", in Epic Illustrated #3. In the story, where Dreadstar is not the main character, he unwittingly aids the Orsirosian named Akhnaton in destroying the

text: Milky Way Galaxy

text: , the only way to stop the ever-expanding Zygotean empire.

text: The Ford 300 is an automobile which was built in the USA by Ford for the model year 1963 only.  It was the base trim level of the full-size 1963 Ford line below the Galaxie, Galaxie 500 & Galaxie 500XL. It featured almost no chrome trim or luxury equipment and could be compared to the Chevrolet Biscayne in trim level.

text: The Ford 300 is an automobile which was built in the USA by

text: Ford

text: for the model year 1963 only.  It was the base trim level of the

text: full-size

text: 1963 Ford line below the

text: Galaxie

text: , Galaxie 500 & Galaxie 500XL. It featured almost no chrome trim or luxury equipment and could be compared to the

text: Chevrolet Biscayne

text: in trim level.

text: The Sagittarius Dwarf Irregular Galaxy or SagDIG is a dwarf galaxy in the constellation of Sagittarius. It lies about 3.4 million light-years away. SagDIG should not be confused with the Sagittarius Dwarf Elliptical Galaxy or SagDEG, a satellite galaxy of the Milky Way.  It was discovered by Cesarsky et al. on a photographic plate taken for the ESO (B) Atlas on June 13, 1977 using the ESO 1 meter Schmidt telescope.

text: The Sagittarius Dwarf Irregular Galaxy or SagDIG is a

text: dwarf galaxy

text: in the

text: constellation

text: of

text: Sagittarius

text: . It lies about 3.4 million

text: light-year

text: s away. SagDIG should not be confused with the

text: Sagittarius Dwarf Elliptical Galaxy

text: or SagDEG, a

text: satellite galaxy

text: of the

text: Milky Way

text: .  It was discovered by Cesarsky et al. on a

text: photographic plate

text: taken for the ESO (B) Atlas on June 13, 1977 using the

text: ESO

text: 1 meter Schmidt telescope.

text: Since the first stars began to form, the Milky Way has grown through both galaxy mergers (particularly early in the Milky Way's growth) and accretion of gas directly from the Galactic halo. The Milky Way is currently accreting material from two of its nearest satellite galaxies, the Large and Small Magellanic Clouds, through the Magellanic Stream. Direct accretion of gas is observed in high-velocity clouds like the Smith Cloud. However, properties of the Milky Way such as stellar mass, angular momentum, and metallicity in its outermost regions suggest it has undergone no mergers with large galaxies in the last 10 billion years. This lack of recent major mergers is unusual among similar spiral galaxies; its neighbour the Andromeda Galaxy appears to have a more typical history shaped by more recent mergers with relatively large galaxies.

text: Since the first stars began to form, the Milky Way has grown through both

text: galaxy merger

text: s (particularly early in the Milky Way's growth) and accretion of gas directly from the Galactic halo. The Milky Way is currently accreting material from two of its nearest satellite galaxies, the

text: Large

text: and

text: Small

text: Magellanic Clouds, through the

text: Magellanic Stream

text: . Direct accretion of gas is observed in

text: high-velocity cloud

text: s like the

text: Smith Cloud

text: . However, properties of the Milky Way such as stellar mass,

text: angular momentum

text: , and

text: metallicity

text: in its outermost regions suggest it has undergone no mergers with large galaxies in the last 10 billion years. This lack of recent major mergers is unusual among similar spiral galaxies; its neighbour the Andromeda Galaxy appears to have a more typical history shaped by more recent mergers with relatively large galaxies.

text: The shells of these very common cowries reach on average of length, with a minimum size of  and a maximum size of .  The shape is usually pear-shaped, the dorsum surface is smooth and shiny and may be pale or dark brown, with several small white spots. The margins and the extremities are clearer, while the base is generally white, with a wide sinuous aperture and long labial teeth. The margins show also numerous thin vertical whitish lines. The juvenile forms have two-three clearer trasversal bands on the shell dorsum.  These shells are quite similar and may be confused with the shells of Lyncina camelopardalis.  In the living cowries the mantle is grey-brown and almost transparent, with long whitish tree-shaped papillae. Mantle and foot are very well developed, usually with external antennae.

text: The shells of these very common cowries reach on average of length, with a minimum size of  and a maximum size of .  The shape is usually pear-shaped, the dorsum surface is smooth and shiny and may be pale or dark brown, with several small white spots. The margins and the extremities are clearer, while the base is generally white, with a wide sinuous aperture and long labial teeth. The margins show also numerous thin vertical whitish lines. The juvenile forms have two-three clearer trasversal bands on the shell dorsum.  These shells are quite similar and may be confused with the shells of

text: Lyncina camelopardalis

text: .  In the living cowries the mantle is grey-brown and almost transparent, with long whitish tree-shaped papillae. Mantle and foot are very well developed, usually with external antennae.

text: Magellanic spiral galaxies are (usually) dwarf galaxies which are classified as the type Sm (and SAm, SBm, SABm). They are galaxies with one single spiral arm, and are named after their prototype, the Large Magellanic Cloud, an SBm galaxy. They can be considered to be intermediate between dwarf spiral galaxies and irregular galaxies.

text: Magellanic spiral galaxies are (usually)

text: dwarf galaxies

text: which are classified as the type Sm (and SAm, SBm, SABm). They are

text: galaxies

text: with one single

text: spiral arm

text: , and are named after their prototype, the

text: Large Magellanic Cloud

text: , an SBm galaxy. They can be considered to be intermediate between

text: dwarf spiral galaxies

text: and

text: irregular galaxies

text: Perseus contains some notable galaxies. NGC 1023 is a barred spiral galaxy of magnitude 10.35, around 11.6 million pc (38 million ly) from Earth. It is the principal member of the NGC 1023 group of galaxies and is possibly interacting with another galaxy. NGC 1260 is either a lenticular or tightly-wound spiral galaxy about 76.7 million pc (250 million ly) from Earth. It was the host galaxy of the supernova SN 2006gy, one of the brightest ever recorded. It is a member of the Perseus cluster (Abell 426), a massive galaxy cluster located 76.6 million pc (250 million ly) from Earth. With a redshift of 0.0179, Abell 426 is the closest major cluster to the Earth. NGC 1275, a component of the cluster, is a Seyfert galaxy containing an active nucleus that produces jets of material, surrounding the galaxy with massive bubbles. These bubbles create sound waves that travel through the Perseus Cluster, sounding a B flat 57 octaves below middle C. This galaxy is a cD galaxy that has undergone many galactic mergers throughout its existence, as evidenced by the "high velocity system"the remnants of a smaller galaxysurrounding it. Its active nucleus is a strong source of radio waves.

text: Perseus contains some notable galaxies.

text: NGC 1023

text: is a

text: barred spiral galaxy

text: of magnitude 10.35, around 11.6 million pc (38 million ly) from Earth. It is the principal member of the

text: NGC 1023 group

text: of galaxies and is possibly interacting with another galaxy.

text: NGC 1260

text: is either a

text: lenticular

text: or tightly-wound

text: spiral galaxy

text: about 76.7 million pc (250 million ly) from Earth. It was the host galaxy of the supernova

text: SN 2006gy

text: , one of the brightest ever recorded. It is a member of the

text: Perseus cluster

text: (Abell 426), a massive

text: galaxy cluster

text: located 76.6 million pc (250 million ly) from Earth. With a

text: redshift

text: of 0.0179, Abell 426 is the closest major cluster to the Earth.

text: NGC 1275

text: , a component of the cluster, is a

text: Seyfert galaxy

text: containing an

text: active nucleus

text: that produces jets of material, surrounding the galaxy with massive bubbles. These bubbles create sound waves that travel through the Perseus Cluster, sounding a

text: B flat

text: octave

text: s below

text: middle C

text: . This galaxy is a

text: cD galaxy

text: that has undergone many

text: galactic merger

text: s throughout its existence, as evidenced by the "high velocity system"the remnants of a smaller galaxysurrounding it. Its active nucleus is a strong source of radio waves.

text: of the Milky Way—its integrated luminosity is about 4000 times that of the Sun (absolute visible magnitude of about −4.2), which is much lower than the luminosity of the majority of globular clusters. Uma II is even less luminous than some stars, like Canopus in the Milky Way. It is comparable in luminosity to Bellatrix in Orion. However, its mass is about 5 million solar masses, which means that galaxy's mass to light ratio is around 2000. This may be an overestimate as the galaxy has somewhat irregular shape and may be in process of tidal disruption.

text: of the

text: Milky Way

text: —its integrated luminosity is about 4000 times that of the Sun (absolute

text: visible magnitude

text: of about −4.2), which is much lower than the luminosity of the majority of

text: globular cluster

text: s. Uma II is even less luminous than some

text: star

text: s, like

text: Canopus

text: in the Milky Way. It is comparable in luminosity to

text: Bellatrix

text: in

text: Orion

text: . However, its mass is about 5 million

text: solar mass

text: es, which means that galaxy's

text: mass to light ratio

text: is around 2000. This may be an overestimate as the galaxy has somewhat irregular shape and may be in process of tidal disruption.

text: Because of their small size, dwarf galaxies have been observed being pulled toward and ripped by neighbouring spiral galaxies, resulting in galaxy merger.

text: Because of their small size, dwarf galaxies have been observed being pulled toward and

text: ripped

text: by neighbouring

text: spiral galaxies

text: , resulting in

text: galaxy merger

text: Mayall's Object (also classified under the Atlas of Peculiar Galaxies as Arp 148) is the result of two colliding galaxies located 500 million light years away within the constellation of Ursa Major. It was discovered by American astronomer Nicholas U. Mayall of the Lick Observatory on 13 March 1940, using the Crossley reflector. When first discovered, Mayall's Object was described as a peculiar nebula, shaped like a question mark. Originally theorized to represent a galaxy reacting with the intergalactic medium, it is now thought to represent the collision of two galaxies, resulting in a new object consisting of a ring-shaped galaxy with a tail emerging from it. It is thought that the original collision between the two original galaxies created a shockwave that initially drew matter into the center which then formed the ring.

text: Mayall's Object (also classified under the

text: Atlas of Peculiar Galaxies

text: as Arp 148) is the result of two colliding galaxies located 500 million light years away within the constellation of

text: Ursa Major

text: . It was discovered by American astronomer

text: Nicholas U. Mayall

text: of the

text: Lick Observatory

text: on 13 March 1940, using the

text: Crossley reflector

text: . When first discovered, Mayall's Object was described as a peculiar nebula, shaped like a question mark. Originally theorized to represent a galaxy reacting with the intergalactic medium, it is now thought to represent the

text: collision

text: of two galaxies, resulting in a new object consisting of a

text: ring-shaped galaxy

text: with a tail emerging from it. It is thought that the original collision between the two original galaxies created a shockwave that initially drew matter into the center which then formed the ring.

text: At the center of the most galaxies is a high concentration of older stars. This portion of a galaxy is called the nuclear bulge. Beyond the nuclear bulge lies a large disc containing young, hot stars, called the disk of the galaxy. There is a morphological separation: Ellipticals are most common in clusters of galaxies, and typically the center of a cluster is occupied by a giant elliptical. Spirals are most common in the field, i.e., not in clusters.

text: At the center of the most galaxies is a high concentration of older stars. This portion of a galaxy is called the

text: nuclear bulge

text: . Beyond the nuclear bulge lies a large disc containing young, hot stars, called the disk of the galaxy. There is a morphological separation: Ellipticals are most common in clusters of galaxies, and typically the center of a cluster is occupied by a giant elliptical. Spirals are most common in the field, i.e., not in clusters.

text: Globular clusters, or GC, are roughly spherical groupings of from 10,000 to several million stars packed into regions of from 10 to 30 light years across. They commonly consist of very old Population II stars—just a few hundred million years younger than the universe itself—which are mostly yellow and red, with mass just less than two solar masses. Such stars predominate within clusters because hotter and more massive stars have exploded as supernovae, or evolved through planetary nebula phases to end as white dwarfs. Yet a few rare blue stars exist in globulars, thought to be formed by stellar mergers in their dense inner regions; these stars are known as blue stragglers.

text: Globular clusters, or GC, are roughly spherical groupings of from 10,000 to several million stars packed into regions of from 10 to 30

text: light year

text: s across. They commonly consist of very old

text: Population II

text: stars—just a few hundred million years younger than the universe itself—which are mostly yellow and red, with mass just less than two

text: solar mass

text: es. Such stars predominate within clusters because hotter and more massive stars have exploded as

text: supernova

text: e, or evolved through

text: planetary nebula

text: phases to end as

text: white dwarf

text: s. Yet a few rare blue stars exist in globulars, thought to be formed by stellar mergers in their dense inner regions; these stars are known as

text: blue straggler

text: s.

text: The Milky Way consists of a bar-shaped core region surrounded by a disk of gas, dust and stars. The gas, dust and stars are organized in roughly logarithmic spiral arm structures (see Spiral arms below). The mass distribution within the Milky Way closely resembles the type Sbc in the Hubble classification, which represents spiral galaxies with relatively loosely wound arms. Astronomers first began to suspect that the Milky Way is a barred spiral galaxy, rather than an ordinary spiral galaxy, in the 1990s. Their suspicions were confirmed by the Spitzer Space Telescope observations in 2005 that showed the Milky Way's central bar to be larger than previously thought.

text: The Milky Way consists of a bar-shaped core region surrounded by a disk of

text: gas, dust

text: and stars. The gas, dust and stars are organized in roughly

text: logarithmic spiral

text: arm structures (see

text: Spiral arms

text: below). The mass distribution within the Milky Way closely resembles the type Sbc in the

text: Hubble classification

text: , which represents spiral galaxies with relatively loosely wound arms. Astronomers first began to suspect that the Milky Way is a

text: barred spiral galaxy

text: , rather than an ordinary

text: spiral galaxy

text: , in the 1990s. Their suspicions were confirmed by the

text: Spitzer Space Telescope

text: observations in 2005 that showed the Milky Way's central bar to be larger than previously thought.

text: Once the distances to nearby clusters have been established, further techniques can extend the distance scale to more distant clusters. By matching the main sequence on the Hertzsprung-Russell diagram for a cluster at a known distance with that of a more distant cluster, the distance to the more distant cluster can be estimated. The nearest open cluster is the Hyades: the stellar association consisting of most of the Plough stars is at about half the distance of the Hyades, but is a stellar association rather than an open cluster as the stars are not gravitationally bound to each other. The most distant known open cluster in our galaxy is Berkeley 29, at a distance of about 15,000 parsecs. Open clusters are also easily detected in many of the galaxies of the Local Group.

text: Once the distances to nearby clusters have been established, further techniques can extend the distance scale to more distant clusters. By matching the

text: main sequence

text: on the Hertzsprung-Russell diagram for a cluster at a known distance with that of a more distant cluster, the distance to the more distant cluster can be estimated. The nearest open cluster is the

text: Hyades

text: : the stellar association consisting of most of the

text: Plough stars

text: is at about half the distance of the Hyades, but is a stellar association rather than an open cluster as the stars are not gravitationally bound to each other. The most distant known open cluster in our galaxy is

text: Berkeley 29

text: , at a distance of about 15,000 parsecs. Open clusters are also easily detected in many of the galaxies of the

text: Local Group

text: No known globular clusters display active star formation, which is consistent with the view that globular clusters are typically the oldest objects in the Galaxy, and were among the first collections of stars to form. Very large regions of star formation known as super star clusters, such as Westerlund 1 in the Milky Way, may be the precursors of globular clusters.

text: No known globular clusters display active star formation, which is consistent with the view that globular clusters are typically the oldest objects in the Galaxy, and were among the first collections of stars to form. Very large regions of star formation known as

text: super star cluster

text: s, such as

text: Westerlund 1

text: in the

text: Milky Way

text: , may be the precursors of globular clusters.

text: All GRBs observed to date have occurred well outside the Milky Way galaxy and have been harmless to Earth. However, if a GRB were to occur within the Milky Way and its emission were beamed straight towards Earth, the effects could be harmful and potentially devastating for the ecosystems. Currently, orbiting satellites detect on average approximately one GRB per day. The closest observed GRB as of March 2014 was GRB 980425, located  away (z=0.0085) in a SBc-type dwarf galaxy. GRB 980425 was far less energetic than the average GRB and was associated with the Type Ib supernova SN 1998bw.

text: All GRBs observed to date have occurred well outside the Milky Way galaxy and have been harmless to Earth. However, if a GRB were to occur within the Milky Way and its emission were beamed straight towards Earth, the effects could be harmful and potentially devastating for the

text: ecosystem

text: s. Currently, orbiting satellites detect on average approximately one GRB per day. The closest observed GRB as of March 2014 was

text: GRB 980425

text: , located  away (

entity_section: Measurement, characterization, and interpretation

text: z

text: =0.0085) in a SBc-type dwarf galaxy. GRB 980425 was far less energetic than the average GRB and was associated with the

text: Type Ib supernova

text: SN 1998bw

text: Virgo possesses several galaxy clusters, one of which is HCG 62. A Hickson Compact Group, HCG 62 is at a distance of  from Earth (redshift 0.0137) and possesses a large central elliptical galaxy. It has a heterogeneous halo of extremely hot gas, posited to be due to the active galactic nucleus at the core of the central elliptical galaxy.

text: Virgo possesses several

text: galaxy cluster

text: s, one of which is

text: HCG 62

text: . A

text: Hickson Compact Group

text: , HCG 62 is at a distance of  from Earth (

text: redshift

text: 0.0137) and possesses a large central elliptical galaxy. It has a heterogeneous halo of extremely hot gas, posited to be due to the

text: active galactic nucleus

text: at the core of the central elliptical galaxy.

text: In 1917, Heber Curtis observed nova S Andromedae within the "Great Andromeda Nebula" (as the Andromeda Galaxy, Messier object M31, was then known). Searching the photographic record, he found 11 more novae. Curtis noticed that these novae were, on average, 10 magnitudes fainter than those that occurred within our galaxy. As a result, he was able to come up with a distance estimate of 150,000 parsecs. He became a proponent of the so-called "island universes" hypothesis, which holds that spiral nebulae are actually independent galaxies.

text: In 1917,

text: Heber Curtis

text: observed nova

text: S Andromedae

text: within the "Great

text: Andromeda

text: Nebula" (as the Andromeda Galaxy,

text: Messier object

text: , was then known). Searching the photographic record, he found 11 more

text: nova

text: e. Curtis noticed that these novae were, on average, 10

text: magnitudes

text: fainter than those that occurred within our galaxy. As a result, he was able to come up with a distance estimate of 150,000

text: parsec

text: s. He became a proponent of the so-called "island universes" hypothesis, which holds that spiral nebulae are actually independent galaxies.

text: Most galaxies are organized into distinct shapes that allow for classification schemes. They are commonly divided into spiral, elliptical and Irregular galaxies.

text: Most

text: galaxies

text: are organized into distinct shapes that allow for classification schemes. They are commonly divided into

text: spiral

text: elliptical

text: and

text: Irregular

text: galaxies.

text: The Bullet Galaxy (RXC J2359.3-6042 CC) is a galaxy in the galaxy cluster RXC J2359.3-6042 (Abell 4067 or ACO 4067). The Bullet Galaxy is the sole component of one half of a cluster merger between the bulk of the cluster and this galaxy, which is plowing through the cluster, similar to how merging clusters Bullet Cluster and Bullet Group have merged. Unlike those, this is an uneven merger between one galaxy and a much larger galaxy cluster. The cluster merger is happening at lower speed than the Bullet Cluster, thus allowing the core of the Bullet Galaxy to retain cool gas and remain relatively undisturbed by its passage through the larger cluster. This cluster merger is the first one observed between a single galaxy and a cluster. The galaxy and cluster lies at redshift z=0.0992, some   away. The galaxy is traveling through the cluster at a speed of .

text: The Bullet Galaxy (RXC J2359.3-6042 CC) is a

text: galaxy

text: in the galaxy cluster

text: RXC J2359.3-6042

text: Abell 4067

text: or

text: ACO 4067

text: ). The Bullet Galaxy is the sole component of one half of a cluster merger between the bulk of the

text: cluster

text: and this galaxy, which is plowing through the cluster, similar to how merging clusters

text: Bullet Cluster

text: and

text: Bullet Group

text: have merged. Unlike those, this is an uneven merger between one galaxy and a much larger galaxy cluster. The cluster merger is happening at lower speed than the Bullet Cluster, thus allowing the core of the Bullet Galaxy to retain cool gas and remain relatively undisturbed by its passage through the larger cluster. This cluster merger is the first one observed between a single galaxy and a cluster. The galaxy and cluster lies at

text: redshift

text: z=0.0992, some   away. The galaxy is traveling through the cluster at a speed of .

text: The Sculptor Galaxy is located at the center of the Sculptor Group, one of the nearest groups of galaxies to the Milky Way.  The Sculptor Galaxy (the brightest galaxy in the group and one of the intrinsically brightest galaxies in the vicinity of ours, only surpassed by the Andromeda Galaxy and the Sombrero Galaxy) and the companion galaxies NGC 247, PGC 2881, PGC 2933, Sculptor-dE1, and UGCA 15 form a gravitationally-bound core near the center of the group.  Most other galaxies associated with the Sculptor Group are only weakly gravitationally bound to this core.

text: The Sculptor Galaxy is located at the center of the

text: Sculptor Group

text: , one of the nearest

text: groups of galaxies

text: to the

text: Milky Way

text: .  The Sculptor Galaxy (the brightest galaxy in the group and one of the intrinsically brightest galaxies in the vicinity of ours, only surpassed by the

text: Andromeda Galaxy

text: and the

text: Sombrero Galaxy

text: ) and the companion galaxies

text: NGC 247

text: PGC 2881

text: PGC 2933

text: , and

text: UGCA 15

text: form a gravitationally-bound core near the center of the group.  Most other galaxies associated with the Sculptor Group are only weakly gravitationally bound to this core.

text: Until 2014, not much was known about the galaxy, other than the fact it was irregular. In early 2014, the galaxy was observed with a 2-foot telescope at the SARA remote observatory in Chile, revealing the galaxy in higher resolution. It appears the galaxy is in the process of forming stars at a high rate - primarily in the red areas in the image. Additionally, the galaxy has several small clumps of stars, implying an ongoing merger.

text: Canes II is directly behind Canes I, which makes it difficult to show which galaxy belongs in which cluster. It is generally accepted that the following galaxies belong in Canes II;

text: According to recent studies, like the Milky Way, the Andromeda Galaxy lies in what in the galaxy color–magnitude diagram is known as the "green valley", a region populated by galaxies in transition from the "blue cloud" (galaxies actively forming new stars) to the "red sequence" (galaxies that lack star formation). Star formation activity in green valley galaxies is slowing as they run out of star-forming gas in the interstellar medium. In simulated galaxies with similar properties, star formation will typically have been extinguished within about five billion years from now, even accounting for the expected, short-term increase in the rate of star formation due to the collision between Andromeda Galaxy and the Milky Way.

text: According to recent studies, like the Milky Way, the Andromeda Galaxy lies in what in the

text: galaxy color–magnitude diagram

text: is known as the "green valley", a region populated by galaxies in transition from the "blue cloud" (galaxies actively forming new stars) to the "red sequence" (galaxies that lack star formation). Star formation activity in green valley galaxies is slowing as they run out of star-forming gas in the interstellar medium. In simulated galaxies with similar properties, star formation will typically have been extinguished within about five billion years from now, even accounting for the expected, short-term increase in the rate of star formation due to the collision between Andromeda Galaxy and the Milky Way.

text: NGC 1569 is characterized by a large  starburst. It has formed stars at a rate 100 times greater than that of the Milky Way during the last 100 million years. It contains two prominent super star clusters with different histories.  Both clusters have experienced episodic star formation.  Super starcluster A, located in the northwest of the galaxy and actually formed of two close clusters (NGC 1569 A1 and NGC 1569 A2), contains young stars (including Wolf-Rayet stars) that formed less than 5 million years ago (in NGC 1569 A1) as well as older red stars (in NGC 1569 A2).Super star cluster B, located near the center of the galaxy, contains an older stellar population of red giants and red supergiants. Both of these star clusters are thought to have masses equivalent to the masses of the globular clusters in the Milky Way (approximately (6-7) × 10 solar masses).  Numerous smaller star clusters, some of them having masses similar to those of small globular clusters or R136 in the Large Magellanic Cloud, with relatively young ages (between 2 million years and 1 billion years) have also been identified. These results, along with the results from other dwarf galaxies such as the Large Magellanic Cloud and NGC 1705, demonstrate that star formation in dwarf galaxies does not occur continuously but instead occurs in a series of short, nearly instantaneous bursts.

text: NGC 1569 is characterized by a large

text: starburst

text: . It has formed stars at a rate 100 times greater than that of the

text: Milky Way

text: during the last 100 million years. It contains two prominent

text: super star cluster

text: s with different histories.  Both clusters have experienced episodic

text: star formation

text: .  Super starcluster A, located in the northwest of the galaxy and actually formed of two close clusters (NGC 1569 A1 and NGC 1569 A2), contains young stars (including

text: Wolf-Rayet stars

text: ) that formed less than 5 million years ago (in NGC 1569 A1) as well as older red stars (in NGC 1569 A2).Super star cluster B, located near the center of the galaxy, contains an older stellar population of

text: red giants

text: and

text: red supergiants

text: . Both of these star clusters are thought to have masses equivalent to the masses of the

text: globular cluster

text: s in the

text: Milky Way

text: (approximately (6-7) × 10

text: solar mass

text: es).  Numerous smaller star clusters, some of them having masses similar to those of small globular clusters or

text: in the Large Magellanic Cloud, with relatively young ages (between 2 million years and 1 billion years) have also been identified. These results, along with the results from other dwarf galaxies such as the

text: Large Magellanic Cloud

text: and

text: NGC 1705

text: , demonstrate that star formation in dwarf galaxies does not occur continuously but instead occurs in a series of short, nearly instantaneous bursts.

text: Image moments cannot generally be used to measure the ellipticity of galaxies without correcting for observational effects, particularly the point spread function.

text: Image moments cannot generally be used to measure the ellipticity of galaxies without correcting for

text: observational effects

text: , particularly the

text: point spread function

text: The Milky Way is a barred spiral galaxy that has a diameter usually considered to be about 100,000–120,000 light-years but may be 150,000–180,000 light-years. The Milky Way is estimated to contain 100–400 billion stars. There are likely at least 100 billion planets in the Milky Way. The Solar System is located within the disk, about 27,000 light-years from the Galactic Center, on the inner edge of one of the spiral-shaped concentrations of gas and dust called the Orion Arm. The stars in the inner ≈10,000 light-years form a bulge and one or more bars that radiate from the bulge. The very center is marked by an intense radio source, named Sagittarius A*, which is likely to be a supermassive black hole.

text: The Milky Way is a

text: barred spiral galaxy

text: that has a diameter usually considered to be about 100,000–120,000

text: light-years

text: but may be 150,000–180,000 light-years. The Milky Way is estimated to contain 100–400 billion

text: star

text: s. There are likely at least 100 billion

text: planets

text: in the Milky Way. The Solar System is located within the disk, about 27,000 light-years from the

text: Galactic Center

text: , on the inner edge of one of the spiral-shaped concentrations of gas and dust called the

text: Orion Arm

text: . The stars in the inner ≈10,000 light-years form a

text: bulge

text: and one or more bars that radiate from the bulge. The very center is marked by an intense radio source, named

text: Sagittarius A*

text: , which is likely to be a

text: supermassive black hole

text: In 1999 a violent outburst at V4641 Sgr was thought to have revealed the location of the closest known black hole to Earth, but later investigation increased its estimated distance by a factor of 15. The complex radio source Sagittarius A is also in Sagittarius, near its western boundary with Ophiuchus. Astronomers believe that one of its components, known as Sagittarius A*, is associated with a supermassive black hole at the center of the galaxy, with a mass of 2.6 million solar masses. The Sagittarius Dwarf Elliptical Galaxy is located just outside the Milky Way.

text: In 1999 a violent outburst at

text: V4641 Sgr

text: was thought to have revealed the location of the closest known black hole to Earth, but later investigation increased its estimated distance by a factor of 15. The complex radio source

text: Sagittarius A

text: is also in Sagittarius, near its western boundary with

text: Ophiuchus

text: . Astronomers believe that one of its components, known as

text: Sagittarius A*

text: , is associated with a

text: supermassive black hole

text: at the

text: center of the galaxy

text: , with a mass of 2.6 million

text: solar mass

text: es. The

text: Sagittarius Dwarf Elliptical Galaxy

text: is located just outside the

text: Milky Way

text: The Lynx Supercluster is a remote supercluster with a redshift of 1.26–1.27. It was the most distant supercluster known at the time of its discovery in 1999. It is made up of two main clusters of galaxies—RX J0849+4452 or Lynx E and RX J0848+4453 or Lynx W—and several smaller clumps. Further still lies the Lynx Arc, located around 12 billion light years away (a redshift of 3.357). It is a distant region containing a million extremely hot, young blue stars with surface temperatures of 80,000–100,000 K that are twice as hot as similar stars in the Milky Way galaxy. Only visible through gravitational lensing produced by a closer cluster of galaxies, the Arc is a feature of the early days of the universe, when "furious firestorms of star birth" were more common.

text: The

text: Lynx Supercluster

text: is a remote

text: supercluster

text: with a redshift of 1.26–1.27. It was the most distant supercluster known at the time of its discovery in 1999. It is made up of two main clusters of galaxies—RX J0849+4452 or Lynx E and RX J0848+4453 or Lynx W—and several smaller clumps. Further still lies the

text: Lynx Arc

text: , located around 12 billion light years away (a redshift of 3.357). It is a distant region containing a million extremely hot, young blue stars with surface temperatures of 80,000–100,000 K that are twice as hot as similar stars in the Milky Way galaxy. Only visible through gravitational lensing produced by a closer cluster of galaxies, the Arc is a feature of the early days of the universe, when "furious firestorms of star birth" were more common.

text: Various shapes such as rectangles, squares, triangles, circles can be used to indicate different roles. Color can be used both for shape borders and connection lines to indicate differences in authority and responsibility, and possibly formal, advisory and informal links between people. A department or position yet to be created or currently vacant might be shown as a shape with a dotted outline. Importance of the position may be shown both with a change in size of the shape in addition to its vertical placement on the chart.

text: Based on the Fairlane and named for a factory experimental Fairlane of 1963, the Thunderbolt combined the light weight of Ford's intermediate-sized body introduced in 1962 with a "high rise"  V8 engine with dual Holley four-barrel carburetors intended for use in the much larger Galaxie.  That engine as used in the Galaxie for NASCAR racing did well, but the Galaxie was simply too heavy an automobile in stock trim to be drag raced successfully; so-called "lightweight" 427-powered Galaxies were built both for stock car racing as well as drag racing during the 1964 model year, although these cars were not modified to the extent of the Thunderbolt.  As installed in the Thunderbolt, the engine was (like all US car motors, due to insurance regulations) conservatively rated at  at 6000 RPM; estimates placed the actual output was close to .In standard form, the Fairlane is  shorter than a Galaxie, rides on a  shorter wheelbase and weighs approximately   less.  Installing the Ford FE V8 in a vehicle intended for an engine no larger than a Ford Windsor/Challenger engine required major reworking and relocation of the car's front suspension components and the modification and strengthening of the suspension mounting areas.  Fiberglass doors, hood, front fenders and even the front bumper on the earliest cars along with Plexiglas side and rear windows aided in weight reduction; the hood with its distinctive raised "teardrop" ram air scoop designed to draw hot air from the engine compartment was pinned in position, eliminating the need for a hood hinges and a latch.  Later cars have aluminum front bumpers in place of the fiberglass units due to racing regulations.

text: Based on the

text: Fairlane

text: and named for a factory experimental Fairlane of 1963, the Thunderbolt combined the light weight of Ford's intermediate-sized body introduced in 1962 with a "high rise"  V8 engine with dual

text: Holley

text: four-barrel carburetors intended for use in the much larger

text: Galaxie

text: .  That engine as used in the Galaxie for

text: NASCAR

text: racing did well, but the Galaxie was simply too heavy an automobile in stock trim to be drag raced successfully; so-called "lightweight" 427-powered Galaxies were built both for stock car racing as well as drag racing during the 1964 model year, although these cars were not modified to the extent of the Thunderbolt.  As installed in the Thunderbolt, the engine was (like all US car motors, due to insurance regulations) conservatively rated at  at 6000 RPM; estimates placed the actual output was close to .In standard form, the Fairlane is  shorter than a Galaxie, rides on a  shorter wheelbase and weighs approximately   less.  Installing the

text: Ford FE V8

text: in a vehicle intended for an engine no larger than a

text: Ford Windsor/Challenger engine

text: required major reworking and relocation of the car's front suspension components and the modification and strengthening of the suspension mounting areas.

text: Fiberglass

text: doors, hood, front fenders and even the front bumper on the earliest cars along with

text: Plexiglas

text: side and rear windows aided in weight reduction; the hood with its distinctive raised "teardrop" ram air scoop designed to draw hot air from the engine compartment was pinned in position, eliminating the need for a hood hinges and a latch.  Later cars have aluminum front bumpers in place of the fiberglass units due to racing regulations.

text: The spacecraft were originally created by Clifford combining shapes then drawing over the top of the resultant silhouette. Due to his lack of artistic training a lot of the designs "..looked bad at first." After repeated attempts the craft started to improve visually, resulting in a collection of ships with different areas to deploy weapons. These areas, hard points, were adjusted throughout development. It was decided that each craft should perform a specific role within each size class, additional craft were created to fill any gaps. Weapons from Babylon 5 and Star Trek were added to the game, whenever the team saw examples which were not emulated within the game they attempted to create them. The randomly generated galaxies were not originally intended. After a time the developers discovered that creating the game's world was too time-consuming. Although the creation of the procedurally generated galaxy aspect took time in itself, once it was completed it grew along with the rest of the project. Balancing the randomly generated galaxies would have proven difficult, but because S.P.A.Z. is an open-world game it allows players to choose which tasks to undertake during play.

text: The spacecraft were originally created by Clifford combining shapes then drawing over the top of the resultant silhouette. Due to his lack of artistic training a lot of the designs "..looked bad at first." After repeated attempts the craft started to improve visually, resulting in a collection of ships with different areas to deploy weapons. These areas, hard points, were adjusted throughout development. It was decided that each craft should perform a specific role within each size class, additional craft were created to fill any gaps. Weapons from Babylon 5 and

text: Star Trek

text: were added to the game, whenever the team saw examples which were not emulated within the game they attempted to create them. The randomly generated galaxies were not originally intended. After a time the developers discovered that creating the game's world was too time-consuming. Although the creation of the procedurally generated galaxy aspect took time in itself, once it was completed it grew along with the rest of the project. Balancing the randomly generated galaxies would have proven difficult, but because S.P.A.Z. is an open-world game it allows players to choose which tasks to undertake during play.

text: Although the galaxies were previously thought to be interacting gravitationally, the newer Hubble image shows little evidence for this. The spiral shapes of the two larger galaxies appear mostly intact, without the distortions typical of interacting galaxies.

text: Although the galaxies were previously thought to be interacting gravitationally, the newer Hubble image shows little evidence for this. The spiral shapes of the two larger galaxies appear mostly intact, without the distortions typical of

text: interacting galaxies

text: Zwicky devoted considerable time to the search for galaxies and the production of catalogs. From 1961 to 1968 he and his colleagues published a comprehensive six volume Catalogue of galaxies and of clusters of galaxies. They were all published in Pasadena, by the California Institute of Technology.

text: Spirals are also a symbol of hypnosis, stemming from the cliché of people and cartoon characters being hypnotized by staring into a spinning spiral (one example being Kaa in Disney's The Jungle Book). They are also used as a symbol of dizziness, where the eyes of a cartoon character, especially in anime and manga, will turn into spirals to show they are dizzy or dazed. The spiral is also found in structures as small as the double helix of DNA and as large as a galaxy. Because of this frequent natural occurrence, the spiral is the official symbol of the World Pantheist Movement.The spiral is also a symbol of the dialectic process and Dialectical monism.

text: Spirals are also a symbol of

text: hypnosis

text: , stemming from the

text: cliché

text: of people and cartoon characters being hypnotized by staring into a spinning spiral (one example being

text: Kaa

text: in Disney's

text: The Jungle Book

text: ). They are also used as a symbol of

text: dizziness

text: , where the eyes of a cartoon character, especially in

text: anime

text: and

text: manga

text: , will turn into spirals to show they are dizzy or dazed. The spiral is also found in structures as small as the

text: double helix

text: of

text: DNA

text: and as large as a

text: galaxy

text: . Because of this frequent natural occurrence, the spiral is the official symbol of the

text: World Pantheist Movement

text: .The spiral is also a symbol of the

text: dialectic

text: process and

text: Dialectical monism

text: Grain size can be measured by the line-fraction or area-fraction methods of ASTM E112.  In the line-fraction methods, a statistical grain size is calculated from the number of grains or grain boundaries intersecting a line of known length or circle of known circumference.  In the area-fraction method, the grain size is calculated from the number of grains inside a known area.  In each case, the measurement is affected by secondary phases, porosity, preferred orientation, exponential distribution of sizes, and non-equiaxed grains.  Image analysis can measure the shape factors of individual grains by ASTM E1382.

text: Grain size can be measured by the line-fraction or area-fraction methods of

text: ASTM

text: E112.  In the line-fraction methods, a statistical grain size is calculated from the number of grains or grain boundaries intersecting a line of known length or circle of known circumference.  In the area-fraction method, the grain size is calculated from the number of grains inside a known area.  In each case, the measurement is affected by secondary phases, porosity,

text: preferred orientation

text: exponential distribution

text: of sizes, and non-equiaxed grains.

text: Image analysis

text: can measure the

entity_name: Shape factor (image analysis and microscopy)

text: shape factor

text: s of individual grains by ASTM E1382.

text: Class: Galaxy refit (also known as the "Galaxy II", "Galaxy-X", and "Dreadnought Cruiser")

text: NGC 488 is an isolated face-on prototypical spiral galaxy.

text: NGC 488

text: is an isolated face-on prototypical spiral galaxy.

text: In 1960, the Starliner hardtop, along with the Sunliner convertible, made up the Galaxie Special Series.  It utilized the high-level Galaxie trim, however the Galaxie name on the trunklid was replaced by Starliner script. In 1961 the Starliner hardtop and Sunliner convertible were part of the Galaxie Series.

text: This supergiant elliptical galaxy is located near the center of the Virgo Cluster. This rich cluster has about 2,000 members and it forms the core of the larger Virgo Supercluster, of which the Local Group, and hence the Milky Way galaxy, is an outlying member. The cluster is organized into at least three distinct subsystems that are associated with the three galaxies M87, M49 and M86, with the one centered around M87 known as Virgo A and the one around M49 as Virgo B. There is a preponderance of elliptical and S0 galaxies around M87, with a chain of elliptical galaxies aligned with the jet. In terms of mass, M87 is a dominant member of the cluster, and hence appears to be moving very little relative to the cluster as a whole. Indeed, M87 is defined as the cluster center. The cluster has a sparse gaseous atmosphere that emits X-rays that decrease in temperature toward the middle, where M87 is located. The combined mass of the cluster is estimated to be (0.15–1.5) × 10 solar masses.

text: This supergiant elliptical galaxy is located near the center of the

text: Virgo Cluster

text: . This rich cluster has about 2,000 members and it forms the core of the larger

text: Virgo Supercluster

text: , of which the

text: Local Group

text: , and hence the

text: Milky Way

text: galaxy, is an outlying member. The cluster is organized into at least three distinct subsystems that are associated with the three galaxies M87,

text: and

text: , with the one centered around M87 known as Virgo A and the one around M49 as Virgo B. There is a preponderance of elliptical and S0 galaxies around M87, with a chain of elliptical galaxies aligned with the jet. In terms of mass, M87 is a dominant member of the cluster, and hence appears to be moving very little relative to the cluster as a whole. Indeed, M87 is defined as the cluster center. The cluster has a sparse gaseous atmosphere that emits X-rays that decrease in temperature toward the middle, where M87 is located. The combined mass of the cluster is estimated to be (0.15–1.5) × 10

text: solar mass

text: es.

text: The most common size is identical to the European number plates' size () . However, a shorter plate is also common (). Most car dealerships now issue the former. Other shapes such as American and motorbike sizes are also available. Number plates can be made over the counter at registration/licensing stores in shopping centers, although the vehicle registration document may be required.

text: The Galaxie Mega Hall (also known as Galaxie de Metz, Galaxie d'Amnéville or simply Le Galaxie) is an indoor arena located in the commune of Amnéville, France (a suburb of Metz). The arena is primarily used for concerts and other music-related events. However, it also houses handball tournaments.

text: The Galaxie Mega Hall (also known as Galaxie de Metz, Galaxie d'Amnéville or simply Le Galaxie) is an indoor arena located in the

text: commune

text: of

text: Amnéville

text: France

text: (a suburb of

text: Metz

text: ). The arena is primarily used for concerts and other music-related events. However, it also houses

text: handball

text: tournaments.

text: Lenticular galaxies share kinematic properties with both spiral and elliptical galaxies. This is due to the significant bulge and disk nature of lenticulars. The bulge component is similar to elliptical galaxies in that it is pressure supported by a central velocity dispersion. This situation is analogous to a balloon, where the motions of the air particles (stars in a bulge's case) are dominated by random motions. However, the kinematics of lenticular galaxies are dominated by the rotationally supported disk. Rotation support implies the average circular motion of stars in the disk is responsible for the stability of the galaxy. Thus kinematics are often used to distinguish lenticular galaxies from elliptical or spiral galaxies. The distinction between spiral galaxies and lenticular galaxies is often simpler to analyze as the dividing line is often set at a particular bulge-to-disk ratio. Determining the distinction between elliptical galaxies and lenticular galaxies often relies on the measurements of velocity dispersion (σ), rotational velocity (v), and ellipticity (ε). In order to differentiate between lenticulars and ellipticals, one typically looks at the v/σ ratio for a fixed ε. For example, a rough criterion for distinguishing between lenticular and elliptical galaxies is that elliptical galaxies have v/σ < 0.5 for ε = 0.3. The motivation behind this criterion is that lenticular galaxies do have prominent bulge and disk components whereas elliptical galaxies have no disk structure. Thus, lenticulars have much larger v/σ ratios than ellipticals due to their non-negligible rotational velocities (due to the disk component) in addition to not having as prominent of a bulge component compared to elliptical galaxies.

text: Lenticular galaxies share kinematic properties with both spiral and elliptical galaxies. This is due to the significant bulge and disk nature of lenticulars. The bulge component is similar to elliptical galaxies in that it is pressure supported by a central

text: velocity dispersion

text: One such frame of reference is the Hubble flow, the apparent motions of galaxy clusters due to the expansion of space. Individual galaxies, including the Milky Way, have peculiar velocities relative to the average flow. Thus, to compare the Milky Way to the Hubble flow, one must consider a volume large enough so that the expansion of the Universe dominates over local, random motions. A large enough volume means that the mean motion of galaxies within this volume is equal to the Hubble flow. Astronomers believe the Milky Way is moving at approximately  with respect to this local co-moving frame of reference. The Milky Way is moving in the general direction of the Great Attractor and other galaxy clusters, including the Shapley supercluster, behind it. The Local Group (a cluster of gravitationally bound galaxies containing, among others, the Milky Way and the Andromeda Galaxy) is part of a supercluster called the Local Supercluster, centered near the Virgo Cluster: although they are moving away from each other at  as part of the Hubble flow, this velocity is less than would be expected given the 16.8 million pc distance due to the gravitational attraction between the Local Group and the Virgo Cluster.

text: One such frame of reference is the

text: Hubble flow

text: , the apparent motions of galaxy clusters due to the

text: expansion of space

text: . Individual galaxies, including the Milky Way, have

text: peculiar velocities

text: relative to the average flow. Thus, to compare the Milky Way to the Hubble flow, one must consider a volume large enough so that the expansion of the Universe dominates over local, random motions. A large enough volume means that the mean motion of galaxies within this volume is equal to the Hubble flow. Astronomers believe the Milky Way is moving at approximately  with respect to this local co-moving frame of reference. The Milky Way is moving in the general direction of the

text: Great Attractor

text: and other

text: galaxy cluster

text: s, including the

text: Shapley supercluster

text: , behind it. The Local Group (a cluster of gravitationally bound galaxies containing, among others, the Milky Way and the Andromeda Galaxy) is part of a

text: supercluster

text: called the

text: Local Supercluster

text: , centered near the

text: Virgo Cluster

text: : although they are moving away from each other at  as part of the Hubble flow, this velocity is less than would be expected given the 16.8 million pc distance due to the gravitational attraction between the Local Group and the Virgo Cluster.

text: Trumpler 16 and Trumpler 14 are the most prominent star clusters in , a giant stellar association in the Carina spiral arm. Another cluster within , , is thought to be an extension of  appearing visually separated only because of an intervening dust lane.  The spectral types of the stars indicate that  formed by a single wave of star formation. Because of the extreme luminosity of the stars formed, their stellar winds push away the clouds of dust, similar to the Pleiades. In a few million years, after the brightest stars have exploded as supernovae, the cluster will slowly die away.  includes most of the stars in the eastern portion of the  association.

text: Trumpler 16 and Trumpler 14 are the most prominent star clusters in , a giant stellar association in the Carina spiral arm. Another cluster within , , is thought to be an extension of  appearing visually separated only because of an intervening dust lane.  The spectral types of the stars indicate that  formed by a single wave of star formation. Because of the extreme luminosity of the stars formed, their stellar winds push away the clouds of dust, similar to the

text: Pleiades

text: . In a few million years, after the brightest stars have exploded as

text: supernova

text: e, the cluster will slowly die away.  includes most of the stars in the eastern portion of the  association.

text: NGC 10 is a spiral galaxy located in the Sculptor constellation.

text: NGC 10 is a

text: spiral galaxy

text: located in the

text: Sculptor

text: constellation.

text: Abell 2256 is a rich nearby galaxy cluster in the Abell catalogue that exhibits a population of ∼ 100 – 200 kpc long steep spectrum synchrotron filaments surrounding the cluster center with significant evidence of merger activity deduced by the presence of two separate X-ray peaks in the X-ray surface brightness distribution. One feature is a Large Relic. The other striking feature in the cluster is a Long Tail whose morphology suggests it is either a one-sided jet or a twin tail structure. The bending of the tails takes place very near the galaxy core where one might expect little impact from the galaxy’s motion through the intergalactic medium, unless the parent galaxy has undergone extreme stripping.

text: Abell 2256 is a rich nearby

text: galaxy cluster

text: in the

text: Abell catalogue

text: that exhibits a population of ∼ 100 – 200 kpc long steep spectrum synchrotron filaments surrounding the cluster center with significant evidence of merger activity deduced by the presence of two separate X-ray peaks in the X-ray surface brightness distribution. One feature is a

text: Large Relic

text: . The other striking feature in the cluster is a Long Tail whose morphology suggests it is either a one-sided jet or a twin tail structure. The bending of the tails takes place very near the galaxy core where one might expect little impact from the galaxy’s motion through the

text: intergalactic medium

text: , unless the parent galaxy has undergone extreme stripping.

text: In astronomy, Galactocentrism is the theory that our sun is at or near the center of the galaxy. Observations by William Herschel in 1785 indicated that the Milky Way was a separate disk-shaped galaxy with the sun in a central position. Although proved incorrect by Harlow Shapley in 1918, the theory was a step in the development of cosmological models as the speculation of the existence of other galaxies, comparable in size and structure to our own, placed the earth in its proper perspective with respect to the rest of the universe.

text: In

text: astronomy

text: , Galactocentrism is the theory that our sun is at or near the center of the

text: galaxy

text: . Observations by

text: William Herschel

text: in 1785 indicated that the

text: Milky Way

text: was a separate disk-shaped galaxy with the sun in a central position. Although proved incorrect by

text: Harlow Shapley

text: in 1918, the theory was a step in the development of

text: cosmological

text: models as the speculation of the existence of other galaxies, comparable in size and structure to our own, placed the earth in its proper perspective with respect to the rest of the

text: universe

text: BCD galaxies cool in the process of forming new stars. The galaxies' stars are all formed at different time periods, so the galaxies have time to cool and to build up matter to form new stars. As time passes, this star formation changes the shape of the galaxies.

text: BCD galaxies cool in the process of

text: forming new stars

text: . The galaxies' stars are all formed at different time periods, so the galaxies have time to cool and to build up matter to form new stars. As time passes, this star formation changes the shape of the galaxies.

text: From these observations APM 08279+5255 is a giant elliptical galaxy with large amounts of gas and dust and an active galactic nucleus (AGN) at its core. The AGN is powered by a supermassive black hole of 23 billion solar masses, one of the  largest known. It is radio-quiet with no evidence for a relativistic jet. The black hole is surrounded by an accretion disk of material spiraling into it, a few parsecs in size. Further out is a dust torus, a doughnut shaped cloud of dust and gas with a radius of about 100 parsecs. Both the accretion disk and dust torus appear to be almost face-on to us. The radiation from the molecular gas is coming from a flattened disk at the center of the galaxy with a radius of 550 pc. This is also the starburst region of the galaxy. The gas is heated both by activity in the AGN and by the newly forming stars.

text: From these observations APM 08279+5255 is a giant elliptical galaxy with large amounts of gas and dust and an

text: active galactic nucleus

text: (AGN) at its core. The AGN is powered by a supermassive black hole of 23 billion solar masses, one of the

text: largest known

text: . It is radio-quiet with no evidence for a

text: relativistic jet

text: . The black hole is surrounded by an accretion disk of material spiraling into it, a few

text: parsec

text: s in size. Further out is a dust torus, a doughnut shaped cloud of dust and gas with a radius of about 100 parsecs. Both the accretion disk and dust torus appear to be almost face-on to us. The radiation from the molecular gas is coming from a flattened disk at the center of the galaxy with a radius of 550 pc. This is also the

text: starburst region

text: of the galaxy. The gas is heated both by activity in the AGN and by the newly forming stars.

text: Adria's story begins shortly after the events of "Beachhead", when Vala is impregnated by the Ori in the Ori home galaxy. Vala eventually returns to the Milky Way aboard one of the Ori battlecruisers invading the Milky Way galaxy. In "Flesh and Blood", Vala gives birth to a baby girl, the Orici. Within hours of being born, the child reaches the apparent age of four and heals her mother's pain, knowing that Vala is not a believer in Origin. By the child's apparent age of seven, Vala gives her the name Adria, after her stepmother, a "witch of a woman". Vala escapes when Adria is at the apparent age of twelve. Adria only starts to have an impact in the second quarter of the season, when she has grown "into a beautiful but deadly young woman".

text: Adria's story begins shortly after the events of "Beachhead", when Vala is impregnated by the Ori in the Ori home galaxy. Vala eventually returns to the Milky Way aboard one of the

text: Ori battlecruiser

text: s invading the Milky Way galaxy. In "Flesh and Blood", Vala gives birth to a baby girl, the Orici. Within hours of being born, the child reaches the apparent age of four and heals her mother's pain, knowing that Vala is not a believer in Origin. By the child's apparent age of seven, Vala gives her the name Adria, after her stepmother, a "witch of a woman". Vala escapes when Adria is at the apparent age of twelve. Adria only starts to have an impact in the second quarter of the season, when she has grown "into a beautiful but deadly young woman".

text: The Andromeda Galaxy's two main companions, M32 and M110 (also known as NGC 221 and NGC 205, respectively) are faint elliptical galaxies that lie near it. M32, visible with a far smaller size of 8.7 by 6.4 arcminutes, compared to M110, appears superimposed on the larger galaxy in a telescopic view as a hazy smudge, M110 also appears slightly larger and distinct from the larger galaxy; M32 is 0.5° south of the core, M32 is 1° northwest of the core. M32 was discovered in 1749 by French astronomer Guillaume Le Gentil and has since been found to lie closer to Earth than the Andromeda Galaxy itself. It is viewable in binoculars from a dark site owing to its high surface brightness of 10.1 and overall magnitude of 9.0. M110 is classified as either a dwarf spheroidal galaxy or simply a generic elliptical galaxy. It is far fainter than M31 and M32, but larger than M42 with a surface brightness of 13.2, magnitude of 8.9, and size of 21.9 by 10.9 arcminutes.

text: The Andromeda Galaxy's two main companions,

text: and

text: (also known as NGC 221 and NGC 205, respectively) are faint elliptical galaxies that lie near it. M32, visible with a far smaller size of 8.7 by 6.4 arcminutes, compared to M110, appears superimposed on the larger galaxy in a telescopic view as a hazy smudge, M110 also appears slightly larger and distinct from the larger galaxy; M32 is 0.5° south of the core, M32 is 1° northwest of the core. M32 was discovered in 1749 by French astronomer

text: Guillaume Le Gentil

text: and has since been found to lie closer to Earth than the Andromeda Galaxy itself. It is viewable in binoculars from a dark site owing to its high surface brightness of 10.1 and overall magnitude of 9.0. M110 is classified as either a

text: dwarf spheroidal galaxy

text: or simply a generic elliptical galaxy. It is far fainter than M31 and M32, but larger than M42 with a surface brightness of 13.2, magnitude of 8.9, and size of 21.9 by 10.9 arcminutes.

text: NGC 7714 and NGC 7715 are interacting galaxies. The pair are also known as Arp 284.  NGC 7714 appears to be a highly distorted spiral, possibly a barred spiral galaxy. NGC 7715 is of uncertain type, probably an edge-on spiral or an irregular galaxy.

text: NGC 7714 and NGC 7715 are interacting galaxies. The pair are also known as Arp 284.  NGC 7714 appears to be a highly distorted spiral, possibly a

text: barred spiral galaxy

text: . NGC 7715 is of uncertain type, probably an edge-on spiral or an

text: irregular galaxy

text: Such major galactic mergers  to have been common at early times, but may occur less frequently today. Minor galactic mergers involve two galaxies of very different masses, and are not limited to giant ellipticals. For example, our own Milky Way galaxy is known to be consuming a couple of small galaxies right now. The Milky Way galaxy is also, depending upon an unknown tangential component, on a collision course in 4–5 billion years with the Andromeda Galaxy. It has been theorized that an elliptical galaxy will result from a merger of the two spirals.

text: Such major galactic mergers  to have been common at early times, but may occur less frequently today. Minor galactic mergers involve two galaxies of very different masses, and are not limited to giant ellipticals. For example, our own

text: Milky Way

text: galaxy is known to be consuming a couple of small galaxies right now. The

text: Milky Way

text: galaxy is also, depending upon an unknown tangential component, on a collision course in 4–5 billion years with the

text: Andromeda Galaxy

text: . It has been theorized that an elliptical galaxy will result from a merger of the two spirals.

text: The Galaxy Tab S series refers to the ultra high-end models: the Samsung Galaxy Tab S 8.4 and the Samsung Galaxy Tab S 10.5 which are aimed to be the flagship model line of Samsung Galaxy tablets together with other Samsung Galaxy S series devices namely the Samsung Galaxy S5. The tablets were announced during the Samsung Galaxy Premier 2014 in New York.

text: The Galaxy Tab S series refers to the ultra high-end models: the Samsung Galaxy Tab S 8.4 and the Samsung Galaxy Tab S 10.5 which are aimed to be the flagship model line of Samsung Galaxy tablets together with other

text: Samsung Galaxy S series

text: devices namely the

text: Samsung Galaxy S5

text: . The tablets were announced during the Samsung Galaxy Premier 2014 in New York.

text: The irregular galaxy NGC 55, the spiral galaxy NGC 300, and their companion galaxies have been considered by many researchers to be part of this group.  However, recent distance measurements to these and other galaxies in the same region of the sky show that NGC 55, NGC 300, and their companions may simply be foreground galaxies that are physically unassociated with the Sculptor Group.

text: The irregular galaxy

text: NGC 55

text: , the spiral galaxy

text: NGC 300

text: , and their companion galaxies have been considered by many researchers to be part of this group.  However, recent distance measurements to these and other galaxies in the same region of the sky show that NGC 55, NGC 300, and their companions may simply be foreground galaxies that are physically unassociated with the Sculptor Group.

text: The situation changes somewhat with the introduction of dark energy or a cosmological constant. A cosmological constant due to a vacuum energy density has the effect of adding a repulsive force between objects which is proportional (not inversely proportional) to distance. Unlike inertia it actively "pulls" on objects which have clumped together under the influence of gravity, and even on individual atoms. However, this does not cause the objects to grow steadily or to disintegrate; unless they are very weakly bound, they will simply settle into an equilibrium state which is slightly (undetectably) larger than it would otherwise have been. As the universe expands and the matter in it thins, the gravitational attraction decreases (since it is proportional to the density), while the cosmological repulsion increases; thus the ultimate fate of the ΛCDM universe is a near vacuum expanding at an ever-increasing rate under the influence of the cosmological constant. However, the only locally visible effect of the accelerating expansion is the disappearance (by runaway redshift) of distant galaxies; gravitationally bound objects like the Milky Way do not expand and the Andromeda galaxy is moving fast enough towards us that it will still merge with the Milky Way in 3 billion years time, and it is also likely that the merged supergalaxy that forms will eventually fall in and merge with the nearby Virgo Cluster. However, galaxies lying farther away from this will recede away at ever-increasing speed and be redshifted out of our range of visibility.

text: The situation changes somewhat with the introduction of dark energy or a cosmological constant. A cosmological constant due to a

text: vacuum energy

text: density has the effect of adding a repulsive force between objects which is proportional (not inversely proportional) to distance. Unlike inertia it actively "pulls" on objects which have clumped together under the influence of gravity, and even on individual atoms. However, this does not cause the objects to grow steadily or to disintegrate; unless they are very weakly bound, they will simply settle into an equilibrium state which is slightly (undetectably) larger than it would otherwise have been. As the universe expands and the matter in it thins, the gravitational attraction decreases (since it is proportional to the density), while the cosmological repulsion increases; thus the ultimate fate of the ΛCDM universe is a near vacuum expanding at an ever-increasing rate under the influence of the cosmological constant. However, the only locally visible effect of the

text: accelerating expansion

text: is the disappearance (by runaway

text: redshift

text: ) of distant galaxies; gravitationally bound objects like the Milky Way do not expand and the Andromeda galaxy is moving fast enough towards us that it will still merge with the Milky Way in 3 billion years time, and it is also likely that the merged supergalaxy that forms will eventually fall in and merge with the nearby

text: Virgo Cluster

text: . However, galaxies lying farther away from this will recede away at ever-increasing speed and be redshifted out of our range of visibility.

text: Much like in cluster-scale weak lensing, detection of a galaxy-galaxy shear signal requires one to measure the shapes of background source galaxies, and then look for statistical shape correlations (specifically, source galaxy shapes should be aligned tangentially, relative to the lens center.)  In principle, this signal could be measured around any individual foreground lens.  In practice, however, due to the relatively low mass of field lenses and the inherent randomness in intrinsic shape of background sources (the "shape noise"), the signal is impossible to measure on a galaxy by galaxy basis.  However, by combining the signals of many individual lens measurements together (a technique known as "stacking"), the signal-to-noise ratio will improve, allowing one to determine a statistically significant signal, averaged over the entire lens set.

text: Much like in

text: cluster-scale weak lensing

text: , detection of a galaxy-galaxy shear signal requires one to measure the shapes of background source galaxies, and then look for statistical shape correlations (specifically, source galaxy shapes should be aligned tangentially, relative to the lens center.)  In principle, this signal could be measured around any individual foreground lens.  In practice, however, due to the relatively low mass of field lenses and the inherent randomness in intrinsic shape of background sources (the "shape noise"), the signal is impossible to measure on a galaxy by galaxy basis.  However, by combining the signals of many individual lens measurements together (a technique known as "stacking"), the

text: signal-to-noise ratio

text: will improve, allowing one to determine a statistically significant signal, averaged over the entire lens set.

text: In the episode "New Order (Part 2)", an Ancient weapon called the Replicator Disruptor was developed by Jack O'Neill while he still had the knowledge of the Ancients in his mind. It works by blocking the cohesion between the blocks that make up the Replicators. The Replicators in the Milky Way galaxy were wiped out by the Dakara Superweapon in the two-part episode "Reckoning" at the climax of Season 8. It has been indicated that the Asgard used the same technology to defeat the Replicators in their own home galaxy as well.

text: In the episode "

text: New Order (Part 2)

text: ", an

text: Ancient

text: weapon called the Replicator Disruptor was developed by

text: Jack O'Neill

text: while he still had the knowledge of the Ancients in his mind. It works by blocking the cohesion between the blocks that make up the Replicators. The Replicators in the Milky Way galaxy were wiped out by the

text: Dakara Superweapon

text: in the two-part episode "

text: Reckoning

text: " at the climax of Season 8. It has been indicated that the Asgard used the same technology to defeat the Replicators in their own home galaxy as well.

text: "Blast off to the outer space high school where the students come in all shapes, sizes and every color of the rainbow! At Galaxy High, the junior class president has six hands. The local pizza parlor is as close as the nearest satellite and when the science teacher gets mad he melts! Join two earthling exchange students as they encounter a crazy collection of cosmic kids from all over the universe."

text: NGC 1084 has been home of 5 supernovae in the last 50 years, 1963P (mag. 14), 1996an (type II, mag. 14), 1998dl (type II, mag. 16), 2009H (type II, mag. 17), and 2012ec (type IIP, mag. 14,5). Star formation in the galaxy is chaotic and not confined at the spiral arms of the galaxy, however, not as high as to classify the galaxy as a starburst galaxy. Star formation has taken place in small bursts in the last 40 million years. The reason of this activity has been proposed to be a merger with a gas-rich dwarf galaxy. A radio source has been detacted 3,5' south-west of the galaxy, connected to it by a bridge.

text: NGC 1084 has been home of 5

text: supernova

text: e in the last 50 years, 1963P (mag. 14), 1996an (type II, mag. 14), 1998dl (type II, mag. 16), 2009H (type II, mag. 17), and 2012ec (type IIP, mag. 14,5). Star formation in the galaxy is chaotic and not confined at the spiral arms of the galaxy, however, not as high as to classify the galaxy as a

text: starburst galaxy

text: . Star formation has taken place in small bursts in the last 40 million years. The reason of this activity has been proposed to be a merger with a gas-rich

text: dwarf galaxy

text: . A radio source has been detacted 3,5' south-west of the galaxy, connected to it by a bridge.

text: NGC 5713 is a peculiar, asymmetric galaxy in the constellation Virgo.  Although classified as a spiral galaxy by most galaxy catalogs, NGC 5713 galaxy is very different from most normal spiral galaxies.  While most spiral galaxies either have either two well-defined spiral arms or a filamentary spiral-like structure, this spiral galaxy has only one visible spiral arm in its disk.  This makes it a galaxy of the Magellanic type. Gravitational interactions with the nearby spiral galaxy NGC 5719 may be responsible for producing the disturbed, asymmetric structure including the single spiral arm.

text: NGC 5713 is a

text: peculiar

text: , asymmetric galaxy in the constellation

text: Virgo

text: .  Although classified as a

text: spiral galaxy

text: by most galaxy catalogs, NGC 5713 galaxy is very different from most normal spiral galaxies.  While most spiral galaxies either have either two well-defined spiral arms or a filamentary spiral-like structure, this spiral galaxy has only one visible spiral arm in its disk.  This makes it a galaxy of the

text: Magellanic type

text: . Gravitational interactions with the nearby spiral galaxy

text: NGC 5719

text: may be responsible for producing the disturbed, asymmetric structure including the single spiral arm.

text: 2006 saw Ford launch two new people carriers – the S-MAX and the Ford Galaxy MK2. Both cars used the same underpinnings, but the S-MAX was a cheaper and sportier alternative to the more upmarket and practical Galaxy. The S-MAX then became the first full-size people carrier to be voted European Car of the Year.

text: 2006 saw Ford launch two new people carriers – the S-MAX and the

text: Ford Galaxy MK2

text: . Both cars used the same underpinnings, but the S-MAX was a cheaper and sportier alternative to the more upmarket and practical Galaxy. The S-MAX then became the first full-size people carrier to be voted

text: European Car of the Year

text: In the astronomical literature, the capitalized word "Galaxy" is often used to refer to our galaxy, the Milky Way, to distinguish it from the other galaxies in our universe. The English term Milky Way can be traced back to a story by Chaucer :

text: In the astronomical literature, the capitalized word "Galaxy" is often used to refer to our galaxy, the

text: Milky Way

text: , to distinguish it from the other galaxies in our

text: universe

text: . The English term Milky Way can be traced back to a story by

text: Chaucer

text: Among the results a psychological bias was demonstrated. Galaxy Zoo scientists had wanted to check whether spiral galaxies were evenly distributed or whether there was some intrinsic property of the Universe that caused galaxies to rotate one way or the other. When the Science team came to analyse the results they found an excess of anti-clockwise spinning spiral galaxies. But when the team checked this bias by asking volunteers to classify the same image which had then been reversed, there was still an excess of anti-clockwise classifications. This demonstrated that the human brain has real difficultly discerning between something rotating clockwise or anti-clockwise. Having measured this effect the team could adjust for it, and went on to establish that spirals which were near each other tended to rotate in the same direction.

text: While NGC 4550 is not one of the brightest galaxies of the Virgo Cluster, its notable as it's one of the few galaxies where a large amount of its stars rotate around the galaxy's center in opposite direction to the others (another, brighter, example is the spiral galaxy NGC 7217). The stars of this galaxy are concentrated in two disks of similar size and surface brightness, one nested within the other and it has been suggested it's the product of the merger between two previous disk galaxies, each one counter-rotating with respect to the other.

text: While NGC 4550 is not one of the brightest galaxies of the Virgo Cluster, its notable as it's one of the few galaxies where a large amount of its stars rotate around the galaxy's center in opposite direction to the others (another, brighter, example is the

text: spiral galaxy

text: NGC 7217

text: ). The stars of this galaxy are concentrated in two disks of similar size and

text: surface brightness

text: , one nested within the other and it has been suggested it's the product of the

text: merger

text: between two previous

text: disk galaxies

text: , each one counter-rotating with respect to the other.

text: Priscilla Fairfield Bok (April 14, 1896 – November 1975) was an American astronomer and the wife of Dutch-born astronomer Bart Bok, Director of Mount Stromlo Observatory in Australia and later of Steward Observatory in Arizona, US. Their harmonious marriage accompanied the four decades of their close scientific collaboration, in which "it is difficult and pointless to separate his achievements from hers". They co-authored a number of academic papers on star clusters, stellar magnitudes, and the structure of the Milky Way galaxy. The Boks displayed great mutual enthusiasm for explaining astronomy to the public: described as "salesmen of the Milky Way" by The Boston Globe, their general interest book The Milky Way went through five editions and was said to be "one of the most successful astronomical texts ever written".

text: Priscilla Fairfield Bok (April 14, 1896 – November 1975) was an American

text: astronomer

text: and the wife of Dutch-born astronomer

text: Bart Bok

text: , Director of

text: Mount Stromlo Observatory

text: in Australia and later of

text: Steward Observatory

text: in Arizona, US. Their harmonious marriage accompanied the four decades of their close scientific collaboration, in which "it is difficult and pointless to separate his achievements from hers". They co-authored a number of academic papers on

text: star cluster

text: s, stellar

text: magnitude

text: s, and the structure of the

text: Milky Way

text: galaxy. The Boks displayed great mutual enthusiasm for explaining astronomy to the public: described as "salesmen of the Milky Way" by

text: The Boston Globe

text: , their general interest book The Milky Way went through five editions and was said to be "one of the most successful astronomical texts ever written".

text: This species resembles other smaller or medium-sized species of Neptosternus. It may be recognized by the size, fairly widely oval shape of its body, the colour-patterns of pronotum and elytra, and the shape of the penis in the males.Its length is between , while its breadth is between .It shape is elongate and oval, moderately convex dorsally; and its upper surface shining. Its head and antennae are yellowish in colour, with fine and remote punctation on the head. It also has a reticulate surface. The pronotum is yellowish with a narrow transverse slightly darker band in the middle, and an anterior submarginal row of punctures that are irregular.

text: This species resembles other smaller or medium-sized species of

text: Neptosternus

text: . It may be recognized by the size, fairly widely oval shape of its body, the colour-patterns of

text: pronotum

text: and

text: elytra

text: , and the shape of the penis in the males.Its length is between , while its breadth is between .It shape is elongate and oval, moderately convex dorsally; and its upper surface shining. Its head and

text: antennae

text: are yellowish in colour, with fine and remote punctation on the head. It also has a reticulate surface. The pronotum is yellowish with a narrow transverse slightly darker band in the middle, and an anterior submarginal row of punctures that are irregular.

text: This category contains spiral galaxies with arms that split into two separate parts.

text: This category contains

text: spiral galaxies

text: with arms that split into two separate parts.

text: Spiral galaxy NGC 3274 is a relatively faint galaxy discovered by Wilhelm Herschel in 1783, and is located over 20 million light-years away in the constellation of Leo.

text: Spiral galaxy

text: NGC 3274 is a relatively faint galaxy discovered by

text: Wilhelm Herschel

text: in 1783, and is located over 20 million light-years away in the

text: constellation of Leo

text: Observations of globular clusters show that these stellar formations arise primarily in regions of efficient star formation, and where the interstellar medium is at a higher density than in normal star-forming regions. Globular cluster formation is prevalent in starburst regions and in interacting galaxies. Research indicates a correlation between the mass of a central supermassive black holes (SMBH) and the extent of the globular cluster systems of elliptical and lenticular galaxies. The mass of the SMBH in such a galaxy is often close to the combined mass of the galaxy's globular clusters.

text: Observations of globular clusters show that these stellar formations arise primarily in regions of efficient star formation, and where the interstellar medium is at a higher density than in normal star-forming regions. Globular cluster formation is prevalent in

text: starburst

text: regions and in

text: interacting galaxies

text: . Research indicates a correlation between the mass of a central

text: supermassive black hole

text: s (SMBH) and the extent of the globular cluster systems of

text: elliptical

text: and

text: lenticular galaxies

text: . The mass of the SMBH in such a galaxy is often close to the combined mass of the galaxy's globular clusters.

text: IC 4889 is an elliptical galaxy of apparent magnitude 11.3, which can be found 2 degrees north-north-west of 5.3-magnitude Nu Telescopii. Observing it through a 40 cm telescope will reveal its central region and halo. The Telescopium group is group of twelve galaxies spanning three degrees in the northeastern part of the constellation, lying around 37 megaparsecs (120 million light-years) from our own galaxy. The brightest member is the elliptical galaxy NGC 6868, and to the west lies the spiral galaxy  (or, perhaps, lenticular galaxy) NGC 6861. These are the brightest members of two respective subgroups within the galaxy group, and are heading toward a merger in the future. Occupying an area of around 4' × 2', NGC 6845 is an interacting system of four galaxies—two spiral and two lenticular galaxies—that is estimated to be around 88 megaparsecs (287 million light-years) distant. SN 2008da was a type II supernova observed in one of the spiral galaxies, NGC 6845A, in June 2008. SN 1998bw was a luminous supernova observed in the spiral arm of the galaxy ESO184-G82 in April 1998, and is notable in that it is highly likely to be the source of the gamma-ray burst GRB 980425.

text: IC 4889

text: is an

text: elliptical galaxy

text: of apparent magnitude 11.3, which can be found 2 degrees north-north-west of 5.3-magnitude

text: Nu Telescopii

text: . Observing it through a 40 cm telescope will reveal its central region and halo. The

text: Telescopium group

text: is group of twelve galaxies spanning three degrees in the northeastern part of the constellation, lying around 37

text: megaparsec

text: s (120 million light-years) from our own galaxy. The brightest member is the elliptical galaxy

text: NGC 6868

text: , and to the west lies the

text: spiral galaxy

text: (or, perhaps,

text: lenticular galaxy

text: NGC 6861

text: . These are the brightest members of two respective subgroups within the galaxy group, and are heading toward a merger in the future. Occupying an area of around 4

text: × 2',

text: NGC 6845

text: is an interacting system of four galaxies—two spiral and two

text: lenticular galaxies

text: —that is estimated to be around 88 megaparsecs (287 million light-years) distant. SN 2008da was a

text: type II supernova

text: observed in one of the spiral galaxies,

text: NGC 6845A

text: , in June 2008.

text: SN 1998bw

text: was a luminous supernova observed in the spiral arm of the galaxy

text: in April 1998, and is notable in that it is highly likely to be the source of the

text: gamma-ray burst

text: GRB 980425

text: Usually, most spiral galaxies contain two clearly defined spiral arms, or they contain only fuzzy filamentary spiral structures. Galaxies with three well-defined spiral arms are rare.

text: In many respects the composition of lenticular galaxies is like that of ellipticals. For example, they both consist of predominately older, hence redder, stars. All of their stars are thought to be older than about a billion years, in agreement with their offset from the Tully–Fisher relation (see below). In addition to these general stellar attributes, globular clusters are found more frequently in lenticular galaxies than in spiral galaxies of similar mass and luminosity. They also have little to no molecular gas (hence the lack of star formation) and no significant hydrogen α or 21-cm emission. Finally, unlike ellipticals, they may still possess significant dust.

text: In many respects the composition of lenticular galaxies is like that of

text: ellipticals

text: . For example, they both consist of predominately older, hence redder, stars. All of their stars are thought to be older than about a billion years, in agreement with their offset from the

text: Tully–Fisher relation

text: (see below). In addition to these general stellar attributes,

text: globular clusters

text: are found more frequently in lenticular galaxies than in spiral galaxies of similar mass and luminosity. They also have little to no molecular gas (hence the lack of star formation) and no significant hydrogen α or 21-cm emission. Finally, unlike ellipticals, they may still possess significant dust.

text: X-shaped galaxies are a sub-class of Fanaroff-Riley Type II (FRII) radio galaxies. FRII objects exhibit a pair of large (kiloparsec) scale radio lobes that straddle the parent elliptical galaxy; the lobes are believed to consist of plasma ejected from the center of the galaxy by jets associated with the accretion disk around the supermassive black hole. Unlike the classical FRII sources, the X-shaped galaxies exhibit two, misaligned pairs of radio lobes of comparable extent. One pair of lobes, the "active" lobes, have a relatively high surface brightness and appear to be generated by ongoing emission from the center of the galaxy. The second set, the "wings", have a lower surface brightness, and appear to consist of plasma that was ejected along a different axis than that associated with the active lobes. The wings are also observed to have a higher spectral index than the active lobes and are highly polarized. With one exception, none of the X-shaped sources shows the broad, optical emission lines associated with quasar activity. The host galaxies mostly exhibit high ellipticities and a number have nearby companion galaxies.

text: X-shaped galaxies are a sub-class of

text: Fanaroff-Riley Type II

text: (FRII)

text: radio galaxies

text: . FRII objects exhibit a pair of large (

text: kiloparsec

text: ) scale radio lobes that straddle the parent elliptical galaxy; the lobes are believed to consist of

text: plasma

text: ejected from the center of the galaxy by jets associated with the

text: accretion disk

text: around the

text: supermassive black hole

text: . Unlike the classical FRII sources, the X-shaped galaxies exhibit two, misaligned pairs of radio lobes of comparable extent. One pair of lobes, the "active" lobes, have a relatively high surface brightness and appear to be generated by ongoing emission from the center of the galaxy. The second set, the "wings", have a lower surface brightness, and appear to consist of plasma that was ejected along a different axis than that associated with the active lobes. The wings are also observed to have a higher

text: spectral index

text: than the active lobes and are highly

text: polarized

text: . With one exception, none of the X-shaped sources shows the broad, optical

text: emission lines

text: associated with

text: quasar

text: activity. The host galaxies mostly exhibit high ellipticities and a number have nearby companion galaxies.

text: The components of the galaxy cluster are the two spiral galaxies NGC 6845A and NGC 6845B as well as the two lenticular galaxies NGC 6845C and NGC 6845D.  The four galaxies occupy an area of about 4' x 2' in the sky.  The largest galaxy in this compact galaxy cluster is NGC 6845A, a barred spiral galaxy.  SN 2008DA was a Type II supernova observed in NGC 6845A in June 2008. The dwarf galaxy ATCA J2001-4659, which is found around 4.4' northeast of NGC 6845B,  was identified as a companion of NGC 6845.

text: The components of the galaxy cluster are the two spiral galaxies NGC 6845A and NGC 6845B as well as the two lenticular galaxies NGC 6845C and NGC 6845D.  The four galaxies occupy an area of about 4' x 2' in the sky.  The largest galaxy in this compact galaxy cluster is NGC 6845A, a

text: barred spiral galaxy

text: .  SN 2008DA was a

text: Type II supernova

text: observed in NGC 6845A in June 2008. The dwarf galaxy ATCA J2001-4659, which is found around 4.4' northeast of NGC 6845B,  was identified as a companion of NGC 6845.

text: The Sculptor Dwarf Galaxy (also known as Sculptor Dwarf Elliptical Galaxy or the Sculptor Dwarf Spheroidal Galaxy) is a dwarf spheroidal galaxy that is a satellite of the Milky Way. The galaxy lies within the constellation Sculptor. It was discovered in 1937 by American astronomer Harlow Shapley using the 24-inch Bruce refractor at Boyden Observatory. The galaxy is located about 290,000 light-years away from the Solar System. The Sculptor Dwarf contains only 4 percent of the carbon and other heavy elements in our own galaxy, the Milky Way, making it similar to primitive galaxies seen at the edge of the universe.

text: The Sculptor Dwarf Galaxy (also known as Sculptor Dwarf Elliptical Galaxy or the Sculptor Dwarf Spheroidal Galaxy) is a

text: dwarf spheroidal galaxy

text: that is a satellite of the

text: Milky Way

text: . The

text: galaxy

text: lies within the

text: constellation

text: Sculptor

text: . It was discovered in 1937 by American astronomer

text: Harlow Shapley

text: using the 24-inch Bruce refractor at

text: Boyden Observatory

text: . The galaxy is located about 290,000

text: light-year

text: s away from the

text: Solar System

text: . The Sculptor Dwarf contains only 4 percent of the carbon and other heavy elements in our own galaxy, the Milky Way, making it similar to primitive galaxies seen at the edge of the universe.

text: Galactic astronomy is the study of the Milky Way galaxy and all its contents. This is in contrast to extragalactic astronomy, which is the study of everything outside our galaxy, including all other galaxies.

text: Galactic astronomy is the study of the

text: Milky Way

text: galaxy and all its contents. This is in contrast to

text: extragalactic astronomy

text: , which is the study of everything outside our galaxy, including all other galaxies.

text: The Canis Major Dwarf Galaxy is classified as an irregular galaxy and is now thought to be the closest neighbouring galaxy to the Earth's location in the Milky Way, being located about 25,000 light-years away from the Solar System and 42,000 light-years from the Galactic Center. It has a roughly elliptical shape and is thought to contain as many stars as the Sagittarius Dwarf Elliptical Galaxy, the previous contender for closest galaxy to our location in the Milky Way.

text: The Canis Major Dwarf Galaxy is classified as an

text: irregular galaxy

text: and is now thought to be the closest neighbouring galaxy to the Earth's location in the

text: Milky Way

text: , being located about 25,000 light-years away from the

text: Solar System

text: and 42,000

text: light-year

text: s from the

text: Galactic Center

text: . It has a roughly elliptical shape and is thought to contain as many stars as the

text: Sagittarius Dwarf Elliptical Galaxy

text: , the previous contender for closest galaxy to our location in the Milky Way.

text: NGC 1433 is a barred spiral galaxy with a double ring structure located in the constellation of Horologium. It is at a distance of 30 million light years from Earth. It has an active galactic nuclei, and NGC 1433 is a Seyfert galaxy that's also known as PGC 13586 which is named Miltron's Galaxy. The central region of the galaxy portraits intense star formation activity, with an irregular star-forming ring of 5" (or 0.3 kpc) radius and weak radio wave emission. Star formation is also noticeable in the spiral arms but not the bar of the galaxy. NGC 1433 is being studied as part of a survey of 50 nearby galaxies known as the Legacy ExtraGalactic UV Survey (LEGUS). A jet of material flowing away from the central black hole of the galaxy extending for only 150 light-years has been found. It is the smallest molecular outflow ever observed in a galaxy beyond our own.

text: NGC 1433 is a

text: barred spiral galaxy

text: with a double ring structure located in the constellation of

text: Horologium

text: . It is at a distance of 30 million

text: light years

text: from Earth. It has an active galactic nuclei, and NGC 1433 is a

text: Seyfert galaxy

text: that's also known as PGC 13586 which is named Miltron's Galaxy. The central region of the galaxy portraits intense star formation activity, with an irregular star-forming ring of 5" (or 0.3 kpc) radius and weak radio wave emission. Star formation is also noticeable in the spiral arms but not the bar of the galaxy. NGC 1433 is being studied as part of a survey of 50 nearby galaxies known as the Legacy ExtraGalactic UV Survey (LEGUS). A jet of material flowing away from the central

text: black hole

text: of the galaxy extending for only 150 light-years has been found. It is the smallest molecular outflow ever observed in a galaxy beyond our own.

text: The Fairlane name was moved to Ford's new intermediate, introduced for the 1962 model year, to bridge the gap between the compact Ford Falcon and the full-sized Galaxie, making it a competitor for GM's A-body "senior compacts", the Dodge Custom 880, and the AMC Rambler. With an overall length of 197 in (5004 mm) and a wheelbase of 115.5 in (2934 mm), it was 16 in (406 mm) longer than the Falcon and 12.3 in (312 mm) shorter than the Galaxie.  Wheel track varied from 53.5 in (1355 mm)  to 56 in (1422 mm) depending on model and specification.

text: The Fairlane name was moved to Ford's new intermediate, introduced for the 1962 model year, to bridge the gap between the compact

text: Ford Falcon

text: and the full-sized

text: Galaxie

text: , making it a competitor for

text: GM's

text: A-body "senior compacts"

text: , the

text: Dodge Custom 880

text: , and the

text: AMC Rambler

text: . With an overall length of 197 in (5004 mm) and a wheelbase of 115.5 in (2934 mm), it was 16 in (406 mm) longer than the Falcon and 12.3 in (312 mm) shorter than the Galaxie.  Wheel track varied from 53.5 in (1355 mm)  to 56 in (1422 mm) depending on model and specification.

text: Due to the Tau Empire's location in the Milky Way Galaxy's Eastern Fringe, combined with their lack of psykers, they have had relatively little contact with the forces of Chaos, which are concentrated around the Eye of Terror in the galaxy's north-west, or the Maelstrom at the center of the galaxy.  The Imperium of Man has for the most part not prioritized military conflict with the Tau, which does occur but at a relatively low level.  Contact with the Eldar is sporadic, and relations vary from one craftworld to the next.  The biggest threats to the Tau Empire come from the Ork hordes, which control vast swathes of the Eastern Fringe, as well as the incursion of the Tyranid Hive Fleets, which tend to enter the galaxy through the Eastern Fringe (ultimately driving towards Terra).  Thus the Tau's two biggest military threats are alien races which possess military doctrines diametrically opposed to those of the Tau.  Both the Orks and Tyranids favor devastating close-quarters combat, while eschewing ranged combat (the Orks to a somewhat lesser degree than the Tyranids).

text: The most prominent open clusters are the Pleiades and Hyades in Taurus. The Double Cluster of h+Chi Persei can also be prominent under dark skies. Open clusters are often dominated by hot young blue stars, because although such stars are short-lived in stellar terms, only lasting a few tens of millions of years, open clusters tend to have dispersed before these stars die.

text: The most prominent open clusters are the

text: Pleiades

text: and

text: Hyades

text: in

text: Taurus

text: . The

text: Double Cluster

text: of

text: h

text: Chi Persei

text: can also be prominent under dark skies. Open clusters are often dominated by hot young blue stars, because although such stars are short-lived in stellar terms, only lasting a few tens of millions of years, open clusters tend to have dispersed before these stars die.

text: The visible radius of Dwingeloo 2 is approximately 2′, which at the distance of 3 Mpc corresponds to about 2 kpc. Dwingeloo 2 has a well defined rotating HI disk inclined at approximately 69° with respect to observer. The distribution of the neutral hydrogen in Dwingeloo 2 is quite irregular, and it is detected as far as 3.2 kpc from the center of the galaxy. The total mass of the galaxy within this radius is estimated at 2.3 billion Solar masses, while the mass of the neutral hydrogen is estimated at about 100 million Solar masses. The total mass of the galaxy is about five times less than that of Dwingeloo 1.

text: The visible radius of Dwingeloo 2 is approximately 2′, which at the distance of 3 Mpc corresponds to about 2 kpc. Dwingeloo 2 has a well defined rotating HI disk inclined at approximately 69° with respect to observer. The distribution of the neutral hydrogen in Dwingeloo 2 is quite irregular, and it is detected as far as 3.2 kpc from the center of the galaxy. The total mass of the galaxy within this radius is estimated at 2.3 billion Solar masses, while the mass of the neutral hydrogen is estimated at about 100 million

text: Solar mass

text: es. The total mass of the galaxy is about five times less than that of Dwingeloo 1.

text: An elliptical galaxy is a type of galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless brightness profile. Unlike flat spiral galaxies with organization and structure, they are more three-dimensional, without much structure, and their stars are in somewhat random orbits around the center.  They are one of the three main classes of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae, along with spiral and lenticular galaxies. Elliptical galaxies range in shape from nearly spherical to highly flat and in size from tens of millions to over one hundred trillion stars. Originally Edwin Hubble hypothesized that elliptical galaxies evolved into spiral galaxies, which was later discovered to be false. Stars found inside of elliptical galaxies are much older than stars found in spiral galaxies.

text: An elliptical galaxy is a type of

text: galaxy

text: having an approximately

text: ellipsoid

text: al shape and a smooth, nearly featureless brightness profile. Unlike flat

text: spiral galaxies

text: with organization and structure, they are more three-dimensional, without much structure, and their stars are in somewhat random orbits around the center.  They are one of the three main

text: classes of galaxy

text: originally described by

text: Edwin Hubble

text: in his 1936 work The Realm of the Nebulae, along with

text: spiral

text: and

text: lenticular

text: galaxies. Elliptical galaxies range in shape from nearly spherical to highly flat and in size from tens of millions to over one hundred trillion

text: star

text: s. Originally Edwin Hubble hypothesized that elliptical galaxies evolved into

text: spiral galaxies

text: , which was later discovered to be false. Stars found inside of elliptical galaxies are much older than stars found in spiral galaxies.

text: NGC 4244, also Caldwell 26, is an edge-on loose Spiral galaxy and Caldwell object in the constellation Canes Venatici. It is part of the M94 Group (the Canes Venatici I Group), a galaxy group relatively close to the Local Group containing the Milky Way.  It shines at magnitude +10.2/+10.6. Its celestial cooridinates are RA , dec . It is located near a naked-eye G-class star Beta Canum Venaticorum, barred spiral galaxy NGC 4151, and irregular galaxy NGC 4214. The galaxy lies approximately 6.5 million/14 million light years away, with a redshift of +243/493 km/s. A nuclear star cluster and halo is located at the centre of this galaxy.

text: NGC 4244, also Caldwell 26, is an edge-on loose

text: Spiral galaxy

text: and

text: Caldwell object

text: in the constellation

text: Canes Venatici

text: . It is part of the

text: M94 Group

text: (the Canes Venatici I Group), a

text: galaxy group

text: relatively close to the

text: Local Group

text: containing the

text: Milky Way

text: .  It shines at magnitude +10.2/+10.6. Its celestial cooridinates are RA , dec . It is located near a naked-eye G-class star

text: Beta Canum Venaticorum

text: barred spiral galaxy

text: NGC 4151

text: , and

text: irregular galaxy

text: NGC 4214

text: . The galaxy lies approximately 6.5 million/14 million light years away, with a redshift of +243/493 km/s. A nuclear

text: star cluster

text: and halo is located at the centre of this galaxy.

text: X-ray astronomy uses X-ray wavelengths. Typically, X-ray radiation is produced by synchrotron emission (the result of electrons orbiting magnetic field lines), thermal emission from thin gases above 10 (10 million) kelvins, and thermal emission from thick gases above 10 Kelvin. Since X-rays are absorbed by the Earth's atmosphere, all X-ray observations must be performed from high-altitude balloons, rockets, or X-ray astronomy satellites. Notable X-ray sources include X-ray binaries, pulsars, supernova remnants, elliptical galaxies, clusters of galaxies, and active galactic nuclei.

text: X-ray astronomy uses

text: X-ray wavelength

text: s. Typically, X-ray radiation is produced by

text: synchrotron emission

text: (the result of electrons orbiting magnetic field lines),

text: thermal emission from thin gases

text: above 10 (10 million)

text: kelvin

text: s, and

text: thermal emission from thick gases

text: above 10 Kelvin. Since X-rays are absorbed by the

text: Earth's atmosphere

text: , all X-ray observations must be performed from

text: high-altitude balloon

text: s,

text: rocket

text: s, or

text: X-ray astronomy satellites

text: . Notable

text: X-ray source

text: s include

text: X-ray binaries

text: pulsar

text: s,

text: supernova remnant

text: s,

text: elliptical galaxies

text: clusters of galaxies

text: , and

text: active galactic nuclei

text: Bicay's research interests include large-scale structure in the universe, the atomic gas content of spiral galaxies, and the infrared properties of galaxies and clusters of galaxies.

text: Torgo was recruited by Empress Dayda of the Sagittarians to fight off Galaxy Master and his Ravager of Worlds (who was Abomination in disguise). Before leaving, Torgo had the computers redesign his frame to make him strong enough to confront his foes. Torgo was joined by Amphibion and Dark-Crawler where they are unable to defeat Abomination (whose strength was doubled by Galaxy Master). Empress Daydra then brought Torgo, Amphibion, and Dark-Crawler to Earth where they became "Hulk-Hunters" so that they can find Hulk and enlist his help to fight Galaxy Master. When they found Hulk, Torgo, Amphibion, and Dark-Crawler found themselves on the losing end of the battle. With help from Empress Daydra, the "Hulk-Hunters" enlisted Hulk's help to fight Galaxy Master. Torgo later renamed the group the "Horror-Hunters" where they fought Galaxy Master while Hulk fought Abomination. When Hulk was able to defeat the empowered Abomination, it weakened Galaxy Master's shields enough for the "Horror-Hunters" to penetrate it. When Galaxy Master teleported Hulk and Abomination so that the "Horror-Hunters" can be defeated, Hulk got angry enough to destroy Galaxy Master and send Abomination into the void of space.

text: Torgo was recruited by Empress Dayda of the Sagittarians to fight off

text: Galaxy Master

text: and his Ravager of Worlds (who was

text: Abomination

text: in disguise). Before leaving, Torgo had the computers redesign his frame to make him strong enough to confront his foes. Torgo was joined by

text: Amphibion

text: and

text: Dark-Crawler

text: where they are unable to defeat Abomination (whose strength was doubled by Galaxy Master). Empress Daydra then brought Torgo, Amphibion, and Dark-Crawler to Earth where they became "Hulk-Hunters" so that they can find

text: Hulk

text: and enlist his help to fight Galaxy Master. When they found Hulk, Torgo, Amphibion, and Dark-Crawler found themselves on the losing end of the battle. With help from Empress Daydra, the "Hulk-Hunters" enlisted Hulk's help to fight Galaxy Master. Torgo later renamed the group the "Horror-Hunters" where they fought Galaxy Master while Hulk fought Abomination. When Hulk was able to defeat the empowered Abomination, it weakened Galaxy Master's shields enough for the "Horror-Hunters" to penetrate it. When Galaxy Master teleported Hulk and Abomination so that the "Horror-Hunters" can be defeated, Hulk got angry enough to destroy Galaxy Master and send Abomination into the void of space.

text: Elliptical and lenticular galaxies are commonly referred to together as “early-type” galaxies, while spirals and irregular galaxies are referred to as “late types”. This nomenclature is the source of the common, but erroneous, belief that the Hubble sequence was intended to reflect a supposed evolutionary sequence, from elliptical galaxies through lenticulars to either barred or regular spirals. In fact, Hubble was clear from the beginning that no such interpretation was implied:

text: Elliptical and lenticular galaxies are commonly referred to together as “early-type” galaxies, while spirals and irregular galaxies are referred to as “late types”. This nomenclature is the source of the common, but erroneous, belief that the Hubble sequence was intended to reflect a supposed

text: evolutionary

text: sequence, from

text: elliptical galaxies

text: through

text: lenticulars

text: to either

text: barred

text: or

text: regular spirals

text: . In fact, Hubble was clear from the beginning that no such interpretation was implied:

text: A grand design spiral galaxy is a type of spiral galaxy with prominent and well-defined spiral arms, as opposed to multi-arm and flocculent spirals which have subtler structural features. The spiral arms of a grand design galaxy extend clearly around the galaxy through many radians and can be observed over a large fraction of the galaxy's radius. As of 2002, approximately 10 percent of all currently known spiral galaxies are classified as grand design type spirals, including M81, M51, M74, M100, and M101.

text: A grand design spiral galaxy is a type of

text: spiral galaxy

text: with prominent and well-defined spiral arms, as opposed to multi-arm and

text: flocculent

text: spirals which have subtler structural features. The spiral arms of a grand design galaxy extend clearly around the galaxy through many

text: radian

text: s and can be observed over a large fraction of the galaxy's radius. As of 2002, approximately 10 percent of

text: all currently known

text: spiral galaxies are classified as grand design type spirals, including

text: , and

text: The galaxy product of the collision has been nicknamed Milkomeda or Milkdromeda. According to simulations, this object will look like a giant elliptical galaxy, but with a center showing less stellar density than current elliptical galaxies. It is however possible the resulting object will be a large disk galaxy, depending on the amount of remaining gas in the Milky Way and Andromeda.

text: The galaxy product of the collision has been nicknamed Milkomeda or Milkdromeda. According to simulations, this object will look like a giant

text: elliptical galaxy

text: , but with a center showing less stellar density than current elliptical galaxies. It is however possible the resulting object will be a large

text: disk galaxy

text: , depending on the amount of remaining gas in the Milky Way and Andromeda.

text: In 1989 he was appointed as a lecturer in the School of Physics at the University of New South Wales (UNSW). He continued the research programs that he brought from the AAO, and soon after arriving at UNSW he (and collaborators from the AAO and the UK) published the most complete catalogue of distant rich galaxy clusters in the Southern sky, that were at redshifts of at least z=0.5. He progressed quickly through the academic ranks, culminating with his appointment as the Head of the School of Physics in 2005. Some of his best-known research works during this period came from a collaboration with his postdoc Dr Kenji Bekki, whose simulations suggested that the strong galactic tide of  the famous Andromeda Galaxy (M31) on its smaller neighbour M32 may well have transformed it from a spiral galaxy into a compact elliptical by stripping away its arms and also triggered a massive star burst in the core, explaining the high density of M32,and in 2003,  in collaboration with Michael Drinkwater at the University of Queensland, he announced the discovery of a new type of galaxy, the ultra-compact dwarf (UCD). In 1995, Couch and Richard Ellis published a picture they took using the Hubble Space Telescope of the galaxy cluster Abell 2218, more than two billion light years away, which showed more than one hundred Einstein arcs – curved streaks of light from even more distant sources which are distorted by the gravity of the cluster. The "2dF Galaxy Redshift Survey" conducted on the AAT was unprecedented in scale: it measured the redshifts of 221,496 unique galaxies, allowing researchers to map the large-scale structure of galaxies in unprecedented detail. During his time at UNSW, he built up the Astrophysics Department to place it in the top 1 per cent of the world's space science institutions, at a time when Couch himself accounted for forty per cent of the department's space science citations.

text: In 1989 he was appointed as a lecturer in the School of Physics at the

text: University of New South Wales

text: (UNSW). He continued the research programs that he brought from the AAO, and soon after arriving at UNSW he (and collaborators from the AAO and the UK) published the most complete catalogue of distant rich galaxy clusters in the Southern sky, that were at

text: redshift

text: s of at least z=0.5. He progressed quickly through the academic ranks, culminating with his appointment as the Head of the School of Physics in 2005. Some of his best-known research works during this period came from a collaboration with his postdoc Dr

text: Kenji Bekki

text: , whose simulations suggested that the strong

text: galactic tide

text: of  the famous

text: Andromeda Galaxy

text: (M31) on its smaller neighbour

text: may well have transformed it from a

text: spiral galaxy

text: into a compact

text: elliptical

text: by stripping away its arms and also triggered a massive star burst in the core, explaining the high density of M32,and in 2003,  in collaboration with

text: Michael Drinkwater

text: at the

text: University of Queensland

text: , he announced the discovery of a new type of galaxy, the

text: ultra-compact dwarf

text: (UCD). In 1995, Couch and

text: Richard Ellis

text: published a picture they took using the Hubble Space Telescope of the galaxy cluster

text: Abell 2218

text: , more than two billion light years away, which showed more than one hundred

text: Einstein arc

text: s – curved streaks of light from even more distant sources which are distorted by the gravity of the cluster. The "2dF Galaxy Redshift Survey" conducted on the AAT was unprecedented in scale: it measured the redshifts of 221,496 unique galaxies, allowing researchers to map the large-scale structure of galaxies in unprecedented detail. During his time at UNSW, he built up the Astrophysics Department to place it in the top 1 per cent of the world's space science institutions, at a time when Couch himself accounted for forty per cent of the department's space science citations.

text: A dwarf galaxy is a small galaxy composed of about 100 million up to several billion stars, a small number compared to the Milky Way's 200–400 billion stars. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is sometimes classified as a dwarf galaxy; others consider it a full-fledged galaxy. Dwarf galaxies' formation and activity are thought to be heavily influenced by interactions with larger galaxies. Astronomers identify numerous types of dwarf galaxies, based on their shape and composition.

text: A dwarf galaxy is a small

text: galaxy

text: composed of about 100 million up to several billion

text: star

text: s, a small number compared to the

text: Milky Way

text: 's 200–400 billion stars. The

text: Large Magellanic Cloud

text: , which closely orbits the Milky Way and contains over 30 billion stars, is sometimes classified as a dwarf galaxy; others consider it a full-fledged galaxy. Dwarf galaxies' formation and activity are thought to be heavily influenced by interactions with larger galaxies. Astronomers identify numerous types of dwarf galaxies, based on their shape and composition.

text: NGC 4777 is an intermediate spiral ring galaxy.

text: NGC 4777 is an

text: intermediate spiral

text: ring

text: galaxy

text: The three largest members of the group (in descending order) are the Andromeda Galaxy, the Milky Way and the Triangulum Galaxy. The larger two of these spiral galaxies each have their own system of satellite galaxies.

text: The three largest members of the group (in descending order) are the Andromeda Galaxy, the Milky Way and the

text: Triangulum Galaxy

text: . The larger two of these

text: spiral galaxies

text: each have their own system of satellite galaxies.

text: Elliptical galaxies have two main stages of evolution. The first is due to the supermassive black hole increasing in size from accreting cooling gas. The second stage is marked by the black hole stabilizing by suppressing gas cooling, thus leaving the elliptical galaxy in a stable state. The mass of the black hole is also correlated to a property called sigma which is the dispersion of the velocities of stars in the elliptical galaxies. This relationship, known as the M-sigma relation, was discovered in 2000. Elliptical galaxies do not have disks around them, although some bulges of disk galaxies look similar to elliptical galaxies. It is more likely to find elliptical galaxies in more crowded regions of the universe (such as galaxy clusters).

text: Elliptical galaxies have two main stages of evolution. The first is due to the supermassive black hole increasing in size from accreting cooling gas. The second stage is marked by the black hole stabilizing by suppressing gas cooling, thus leaving the elliptical galaxy in a stable state. The mass of the black hole is also correlated to a property called

text: sigma

text: which is the dispersion of the velocities of stars in the elliptical galaxies. This relationship, known as the

text: M-sigma relation

text: , was discovered in 2000. Elliptical galaxies do not have disks around them, although some

text: bulges

text: of disk galaxies look similar to elliptical galaxies. It is more likely to find elliptical galaxies in more crowded regions of the universe (such as

text: galaxy cluster

text: s).

text: When two quasars are so nearly in the same direction as seen from Earth that they appear to be a single quasar but may be separated by the use of telescopes, they are referred to as a "double quasar", such as the Twin Quasar. These are two different quasars, and not the same quasar that is gravitationally lensed. This configuration is similar to the optical double star. Two quasars, a "quasar pair", may be closely related in time and space, and be gravitationally bound to one another. These may take the form of two quasars in the same galaxy cluster. This configuration is similar to two prominent stars in a star cluster. A "binary quasar", may be closely linked gravitationally and form a pair of interacting galaxies. This configuration is similar to that of a binary star system.

text: When two quasars are so nearly in the same direction as seen from Earth that they appear to be a single quasar but may be separated by the use of telescopes, they are referred to as a "double quasar", such as the Twin Quasar. These are two different quasars, and not the same quasar that is gravitationally lensed. This configuration is similar to the optical

text: double star

text: . Two quasars, a "quasar pair", may be closely related in time and space, and be gravitationally bound to one another. These may take the form of two quasars in the same

text: galaxy cluster

text: . This configuration is similar to two prominent stars in a

text: star cluster

text: . A "binary quasar", may be closely linked gravitationally and form a pair of

text: interacting galaxies

text: . This configuration is similar to that of a

text: binary star

text: system.

text: NGC 5829 is a spiral galaxy in the constellation Boötes that is interacting with the irregular galaxy IC 4526. Together, the two form the galaxy pair Arp 42.

text: NGC 5829 is a

text: spiral galaxy

text: in the constellation

text: Boötes

text: that is interacting with the

text: irregular galaxy

text: IC 4526. Together, the two form the galaxy pair Arp 42.

text: PKS 1302-102 is a quasar with a binary-supermassive black hole pair, located in the Virgo constellation, some  away. It is the first quasar discovered with two supermassive black holes sitting within its accretion disc. As of 2015, it is one of the few black hole binaries known, and was found in a survey of quasar variability in a group of 20 candidates, and the best candidate known, better than the prior best, OJ 287. The quasar is hosted by an elliptical galaxy. There are two neighbouring galaxies near the quasar.

text: PKS 1302-102 is a

text: quasar

text: with a binary-

text: supermassive black hole

text: pair, located in the

text: Virgo constellation

text: , some  away. It is the first quasar discovered with two supermassive black holes sitting within its

text: accretion disc

text: . As of 2015, it is one of the few black hole binaries known, and was found in a survey of quasar variability in a group of 20 candidates, and the best candidate known, better than the prior best,

text: OJ 287

text: . The quasar is hosted by an

text: elliptical galaxy

text: . There are two neighbouring galaxies near the quasar.

text: NGC 3501 is a spiral galaxy located 80 million light years away.

text: The Hercules Cluster (Abell 2151) is a cluster of galaxies in Hercules.

text: The

text: Hercules Cluster

text: (Abell 2151) is a cluster of galaxies in Hercules.

text: Comparing a GP to the Milky Way can be useful when trying to visualize these star-forming rates. An average GP has a mass of ~3,200 million  (~3,200 million solar masses). The Milky Way (MW) is a spiral galaxy and has a mass of ~1,125,000, million  (~1,125,000 million solar masses). So the MW has the mass of ~390 GPs.

text: Comparing a GP to the

text: Milky Way

text: can be useful when trying to visualize these star-forming rates. An average GP has a mass of ~3,200 million  (~3,200 million solar masses). The Milky Way (MW) is a

text: spiral galaxy

text: and has a mass of ~1,125,000, million  (~1,125,000 million solar masses). So the MW has the mass of ~390 GPs.

text: Because little was known at the time of publication about the physical processes that caused the different shapes, the galaxies in the atlas are sorted based on their appearance. Objects 1–101 are individual peculiar spiral galaxies or spiral galaxies that apparently have small companions.  Objects 102–145 are elliptical and elliptical-like galaxies. Individual or groups of galaxies with neither elliptical nor spiral shapes are listed as objects 146–268. Objects 269–327 are double galaxies. Finally, objects that simply do not fit into any of the above categories are listed as objects 332–338. Most objects are best known by their other designations, but a few galaxies are best known by their Arp numbers (such as Arp 220).

text: Because little was known at the time of publication about the physical processes that caused the different shapes, the galaxies in the atlas are sorted based on their appearance. Objects 1–101 are individual peculiar spiral galaxies or spiral galaxies that apparently have small companions.  Objects 102–145 are elliptical and elliptical-like galaxies. Individual or groups of galaxies with neither elliptical nor spiral shapes are listed as objects 146–268. Objects 269–327 are double galaxies. Finally, objects that simply do not fit into any of the above categories are listed as objects 332–338. Most objects are best known by their other designations, but a few galaxies are best known by their Arp numbers (such as

text: Arp 220

text: They provide excellent ventilation especially during summer and aesthetically as well.  Some of them are especially made to be placed over kitchen and bathroom for the smoke to escape.  Over a period of time, these tiles become dark to black from constant exposure to soot and smoke. These red colored clay tiles, unique in shape and size are so famous and export to all the corners of world. They are unique and are made or available in different size and shapes depending on the users need.

text: They provide excellent ventilation especially during summer and

text: aesthetic

text: ally as well.  Some of them are especially made to be placed over kitchen and bathroom for the smoke to escape.  Over a period of time, these tiles become dark to black from constant exposure to

text: soot

text: and smoke. These red colored clay tiles, unique in shape and size are so famous and export to all the corners of world. They are unique and are made or available in different size and shapes depending on the users need.

text: NGC 1365, also known as the Great Barred Spiral Galaxy, is a barred spiral galaxy about 56 million light-years away in the constellation Fornax.The core is an oval shape with an apparent size of about 50″ × 40″.The spiral arms extend in a wide curve north and south from the ends of the east-west bar and form an almost ring like Z-shaped halo. The central mass in active galactic nucleus rotates close to relativistic limit (the dimensionless spin parameter is larger than 0.84).

text: NGC 1365, also known as the Great Barred Spiral Galaxy, is a

text: barred spiral galaxy

text: about

text: 56 million

text: light-year

text: s away in the

text: constellation

text: Fornax

text: .The core is an oval shape with an apparent size of about 50″ × 40″.The spiral arms extend in a wide curve north and south from the ends of the east-west bar and form an almost

text: ring like

text: Z-shaped halo. The central mass in

text: active galactic nucleus

text: rotates close to relativistic limit (the dimensionless spin parameter is larger than 0.84).

text: The properties of a galaxy can also be determined by analyzing the stars found within them.  NGC 4550, a galaxy in the Virgo Cluster, has a large portion of its stars rotating in the opposite direction as the other portion. It is believed that the galaxy is the combination of two smaller galaxies that were rotating in opposite directions to each other. Bright stars in galaxies can also help determine the distance to a galaxy, which may be a more accurate method than parallax or standard candles.

text: The properties of a galaxy can also be determined by analyzing the stars found within them.

text: NGC 4550

text: , a galaxy in the Virgo Cluster, has a large portion of its stars rotating in the opposite direction as the other portion. It is believed that the galaxy is the combination of two smaller galaxies that were rotating in opposite directions to each other. Bright stars in galaxies can also help determine the distance to a galaxy, which may be a more accurate method than

text: parallax

text: or

text: standard candles

text: Most stars form in open clusters, but very few planets have been found in open clusters and this led to the hypothesis that the open-cluster environment hinders planet formation. However, a 2011 study concluded that there have been an insufficient number of surveys of clusters to make such a hypothesis.The lack of surveys was because there are relatively few suitable open clusters in the Milky Way.Recent discoveries of both giant planets and low-mass planets<ref>The same frequency of planets inside and outside open clusters of stars,   Søren Meibom,

text: Most stars form in

text: open cluster

text: s, but very few planets have been found in open clusters and this led to the hypothesis that the open-cluster environment hinders

text: planet formation

text: . However, a 2011 study concluded that there have been an insufficient number of surveys of clusters to make such a hypothesis.The lack of surveys was because there are relatively few suitable open clusters in the Milky Way.Recent discoveries of both giant planets and low-mass planets<ref>The same frequency of planets inside and outside open clusters of stars,   Søren Meibom,

text: NGC 3226 is a dwarf elliptical galaxy that is interacting with the spiral galaxy NGC 3227.  The two galaxies are one of several examples of a spiral with a dwarf elliptical companion that are listed in the Atlas of Peculiar Galaxies.  Both galaxies may be found in the constellation Leo.

text: NGC 3226 is a

text: dwarf elliptical galaxy

text: that is interacting with the

text: spiral galaxy

text: NGC 3227

text: .  The two galaxies are one of several examples of a spiral with a dwarf elliptical companion that are listed in the

text: Atlas of Peculiar Galaxies

text: .  Both galaxies may be found in the

text: constellation

text: Leo

text: As of October 2016, the full list of Galaxy Zoo projects (13) is: Galaxy Zoo 1, Galaxy Zoo 2, Galaxy Zoo Mergers,Galaxy Zoo Supernovae, Galaxy Zoo Hubble, Galaxy Zoo CANDELS, Radio Galaxy Zoo, Galaxy Zoo Quench, Galaxy Zoo DECALS 1, Galaxy Zoo DECALS2 + SDSS, Illustris, UKIDSS and Galaxy Zoo Bar Lengths.

text: It is one of the largest and brightest nearby galaxies, similar in size and luminosity to the Andromeda Galaxy.

text: It is one of the largest and brightest nearby galaxies, similar in size and luminosity to the

text: Andromeda Galaxy

text: For distant galaxies and AGNs observations are made of the overall shape and properties of the galaxy, as well as the groupings where they are found. Observations of certain types of variable stars and supernovae of known luminosity, called standard candles, in other galaxies allows the inference of the distance to the host galaxy. The expansion of space causes the spectra of these galaxies to be shifted, depending on the distance, and modified by the Doppler effect of the galaxy's radial velocity. Both the size of the galaxy and its redshift can be used to infer something about the distance of the galaxy. Observations of large numbers of galaxies are referred to as redshift surveys, and are used to model the evolution of galaxy forms.

text: For distant

text: galaxies

text: and

text: AGNs

text: observations are made of the overall shape and properties of the galaxy, as well as the

text: groupings

text: where they are found. Observations of certain types of

text: variable star

text: s and

text: supernova

text: e of known

text: luminosity

text: , called

text: standard candle

text: s, in other galaxies allows the inference of the distance to the host galaxy. The expansion of space causes the spectra of these galaxies to be shifted, depending on the distance, and modified by the

text: Doppler effect

text: of the galaxy's radial velocity. Both the size of the galaxy and its

text: redshift

text: can be used to infer something about the distance of the galaxy. Observations of large numbers of galaxies are referred to as

text: redshift survey

text: s, and are used to model the evolution of galaxy forms.

text: NGC 3982 is a member of the M109 Group, a group of galaxies located in the constellation Ursa Major that may contain over 50 galaxies. The group was named after the brightest galaxy in the group, the spiral galaxy M109.

text: NGC 3982 is a member of the

text: M109 Group

text: , a

text: group of galaxies

text: located in the constellation

text: Ursa Major

text: that may contain over 50 galaxies. The group was named after the brightest galaxy in the group, the

text: spiral galaxy

text: Tuning wrench sockets may be square shaped or 8-pointed star shaped, and are found in two basic sizes: a large size for pianos, and a smaller size for most other instruments. For pianos, there are some gradations of size, and several lengths are generally available, and unlike machine-screw sockets which have no taper, piano sockets have a slight taper, to fit tapered tuning pins. Impact piano tuning levers differ from traditional levers in that they are fitted with a weight at the end of the handle. The tuner flicks the lever with his or her wrist, causing the weight to do the actual work of moving the tuning pin. Tuning wrench sockets are often attached snugly to the handle with fine-gauge machine-screw threads, to provide a very firm, immobile joint; this is contrast to the square snap-on joints found in sockets used for machinery.

text: The Jewel Box cluster is one of the youngest known open clusters.  The mean radial velocity of the Jewel Box cluster is .  The brightest stars in the Jewel Box cluster are supergiants, and include some of the brightest stars in the Milky Way galaxy.

text: The Jewel Box cluster is one of the youngest known

text: open cluster

text: s.  The mean

text: radial velocity

text: of the Jewel Box cluster is .  The brightest stars in the Jewel Box cluster are

text: supergiant

text: s, and include some of the brightest stars in the

text: Milky Way galaxy

text: The merging between such large galaxies is regarded as violent, but because of the vast distances between stars, there are essentially no stellar collisions involved in a collision between two galaxies. However, the frictional interaction of the gas between the two galaxies can cause gravitational shock waves, which are capable of forming new stars as the elliptical galaxy forms. By sequencing several images of different galactic collisions, one can observe the timeline of two spiral galaxies merging into a single elliptical galaxy.

text: Irregular galaxies are chaotic in appearance, and are neither spiral nor elliptical. About a quarter of all galaxies are irregular, and the peculiar shapes of such galaxies may be the result of gravitational interaction.

text: The Magellanic Clouds (or Nubeculae Magellani) are two irregular dwarf galaxies visible from the southern hemisphere; they are members of the Local Group and are orbiting the Milky Way galaxy. Because they both show signs of a bar structure, they are often reclassified as Magellanic spiral galaxies.  The two galaxies are:

text: The Magellanic Clouds (or Nubeculae Magellani) are two

text: irregular

text: dwarf

text: galaxies

text: visible from the

text: southern hemisphere

text: ; they are members of the

text: Local Group

text: and are

text: orbit

text: ing the

text: Milky Way

text: galaxy

text: . Because they both show signs of a bar structure, they are often reclassified as

text: Magellanic spiral

text: galaxies.  The two galaxies are:

text: The sizes and shapes differ from the other groups, being generally larger, heavier, and with more complicated shapes, made in double (two-part) moulds in a process apparently invented by the potters of Jun ware. Many of the rims are irregular, forming flower-like shapes. There are also incisions on the bases of many pieces, of the characters feng hua, the name of a building in the main Song palace at Kaifeng (in at least one case this is a Qing addition).  Other pieces have numbers between one and ten impressed on the base.  These may indicate standard sizes to help the palace in ordering, the most likely explanation, or members of matching sets.  If the numbers indicate sizes, "1" is the largest and "10" the smallest". Such pieces are sometimes called "numbered Jun ware".  There are also some simple table shapes made to the same quality, but these are never numbered.

text: The sizes and shapes differ from the other groups, being generally larger, heavier, and with more complicated shapes, made in double (two-part) moulds in a process apparently invented by the potters of Jun ware. Many of the rims are irregular, forming flower-like shapes. There are also incisions on the bases of many pieces, of the characters feng hua, the name of a building in the main Song palace at

text: Kaifeng

text: (in at least one case this is a Qing addition).  Other pieces have numbers between one and ten impressed on the base.  These may indicate standard sizes to help the palace in ordering, the most likely explanation, or members of matching sets.  If the numbers indicate sizes, "1" is the largest and "10" the smallest". Such pieces are sometimes called "numbered Jun ware".  There are also some simple table shapes made to the same quality, but these are never numbered.

text: Although the precise mass of these stars cannot be known, it is estimated that together they make up 10 percent of the mass of the Virgo cluster of galaxies. This means that, most likely, these stars collectively have a larger mass than any particular one of the 2500 galaxies that form the Virgo cluster.

text: At the centre of the Hubble tuning fork, where the two spiral-galaxy branches and the elliptical branch join, lies an intermediate class of galaxies known as lenticulars and given the symbol S0. These galaxies consist of a bright central bulge, similar in appearance to an elliptical galaxy, surrounded by an extended, disk-like structure. Unlike spiral galaxies, the disks of lenticular galaxies have no visible spiral structure and are not actively forming stars in any significant quantity. The bulge component is often the dominant source of light in a lenticular galaxy.

text: At the centre of the Hubble tuning fork, where the two spiral-galaxy branches and the elliptical branch join, lies an intermediate class of galaxies known as

text: lenticulars

text: and given the symbol S0. These galaxies consist of a bright central

text: bulge

text: , similar in appearance to an

text: elliptical galaxy

text: , surrounded by an extended,

text: disk

text: -like structure. Unlike

text: spiral galaxies

text: , the disks of lenticular galaxies have no visible spiral structure and are not actively forming stars in any significant quantity. The bulge component is often the dominant source of light in a lenticular galaxy.

text: The object was first observed in November 2004, in which it was seen as a source emitting X-rays in the outskirts of the spiral galaxy ESO 243-49 and was catalogued as 2XMM J011028.1-460421, but nicknamed "HLX-1". In 2008, a team of astronomers led by Natalie Webb at the Institut de Recherche en Astrophysique et Planétologie in Toulouse, France, discovered HLX-1 and from the very high X-ray luminosity (~1 x 10 erg s, 0.2-10.0 keV), as well as its X-ray characteristics, proposed that it was an intermediate mass black hole candidate. Follow up analysis using further X-ray, optical  and radio  observations support the intermediate-mass black hole nature. In 2012, further work showed that there was a small cluster of stars amassed around HLX-1, leading Sean Farrell and collaborators to conclude that the black hole was once the galactic center of a dwarf galaxy, which was consumed by ESO 243-49. Farrell remarked, "The fact that there's a very young cluster of stars indicates that the intermediate-mass black hole may have originated as the central black hole in a very low-mass dwarf galaxy. The dwarf galaxy was then swallowed by the more massive galaxy.".

text: The object was first observed in November 2004, in which it was seen as a source emitting X-rays in the outskirts of the

text: spiral galaxy

text: ESO 243-49 and was catalogued as 2XMM J011028.1-460421, but nicknamed "HLX-1". In 2008, a team of astronomers led by Natalie Webb at the Institut de Recherche en Astrophysique et Planétologie in

text: Toulouse

text: France

text: , discovered HLX-1 and from the very high X-ray luminosity (~1 x 10 erg s, 0.2-10.0 keV), as well as its X-ray characteristics, proposed that it was an intermediate mass black hole candidate. Follow up analysis using further X-ray, optical  and radio  observations support the intermediate-mass black hole nature. In 2012, further work showed that there was a small cluster of stars amassed around HLX-1, leading Sean Farrell and collaborators to conclude that the black hole was once the galactic center of a dwarf galaxy, which was consumed by ESO 243-49. Farrell remarked, "The fact that there's a very young cluster of stars indicates that the intermediate-mass black hole may have originated as the central black hole in a very low-mass dwarf galaxy. The dwarf galaxy was then swallowed by the more massive galaxy.".

text: Elliptical galaxies vary greatly in both size and mass, from as little as a tenth of a kiloparsec to over 100 kiloparsecs, and from 10 to nearly 10 solar masses. This range is much broader for this galaxy type than for any other. The smallest, the dwarf elliptical galaxies, may be no larger than a typical globular cluster, but contain a considerable amount of dark matter not present in clusters. Most of these small galaxies may not be related to other ellipticals.

text: Elliptical galaxies vary greatly in both size and mass, from as little as a tenth of a

text: kiloparsec

text: to over 100 kiloparsecs, and from 10 to nearly 10 solar masses. This range is much broader for this galaxy type than for any other. The smallest, the

text: dwarf elliptical galaxies

text: , may be no larger than a typical

text: globular cluster

text: , but contain a considerable amount of

text: dark matter

text: not present in clusters. Most of these small galaxies may not be related to other ellipticals.

text: The central cD galaxy of the cluster hosts an active galactic nucleus, which is powered by a central supermassive black hole like those of other galaxies. But the central black hole is devouring matter and is continuously growing at a rate of 60  every year. The central black hole has an estimated mass of on the order of 20 billion . This makes it one of the most massive black holes known in the universe, 5,000 times the mass of the black hole at the center of the Milky Way. The diameter of the black hole's immense event horizon is on the order of 118 billion kilometres, 19 times the distance from the Sun to Pluto, and has the mass equivalent to that of two dwarf galaxies.

text: The central cD galaxy of the cluster hosts an

text: active galactic nucleus

text: , which is powered by a central

text: supermassive black hole

text: like those of other galaxies. But the central black hole is devouring matter and is continuously growing at a rate of 60  every year. The central black hole has an estimated mass of on the order of 20 billion . This makes it one of the

text: most massive black holes

text: known in the universe, 5,000 times the mass of the black hole at the center of the

text: Milky Way

text: . The diameter of the black hole's immense

text: event horizon

text: is on the order of 118 billion kilometres, 19 times the distance from the

text: Sun

text: to

text: Pluto

text: , and has the mass equivalent to that of two dwarf galaxies.

text: NGC 6104 is a barred spiral galaxy located in the constellation Corona Borealis. It is designated as S(R)Pec in the galaxy morphological classification scheme, though it is clearly a barred spiral (deserving of the SB(R)Pec designation), and was discovered by William Herschel on 16 May 1787. The galaxy is approximately 388 million light-years away.

text: NGC 6104 is a

text: barred spiral galaxy

text: located in the constellation

text: Corona Borealis

text: . It is designated as S(R)Pec in the

text: galaxy morphological classification scheme

text: , though it is clearly a barred spiral (deserving of the SB(R)Pec designation), and was discovered by

text: William Herschel

text: on 16 May 1787. The galaxy is approximately 388 million light-years away.

text: Hubble originally described three classes of spiral galaxy. This was extended by de Vaucouleurs to include a fourth class:

text: Hubble originally described three classes of spiral galaxy. This was extended by

text: de Vaucouleurs

text: to include a fourth class:

text: On 2 March 2007, a team of astronomers reported the detection of comet galaxy in this cluster.  This galaxy is being ripped apart by the cluster’s gravitational field and harsh environment. The finding sheds light on the mysterious process by which gas-rich spiral-shaped galaxies might evolve into gas-poor irregular- or elliptical-shaped galaxies over billions of years.

text: On 2 March 2007, a team of astronomers reported the detection of

text: comet galaxy

text: in this cluster.  This galaxy is being ripped apart by the cluster’s gravitational field and harsh environment. The finding sheds light on the mysterious process by which gas-rich spiral-shaped galaxies might evolve into gas-poor irregular- or elliptical-shaped galaxies over billions of years.

text: Dwarf galaxies are small galaxies ranging from hundreds to a few billion stars. Many large galaxies including our own Milky Way Galaxy have several of these smaller dwarf galaxies orbiting them. The deep imaging of DES makes it an ideal probe for finding more dwarf or ‘satellite’ galaxies around our Milky Way Galaxy.

text: Dwarf galaxies

text: are small galaxies ranging from hundreds to a few billion stars. Many large galaxies including our own

text: Milky Way Galaxy

text: have several of these smaller dwarf galaxies orbiting them. The deep imaging of DES makes it an ideal probe for finding more dwarf or ‘satellite’ galaxies around our Milky Way Galaxy.

text: The Milky Way galaxy is a member of an association named the Local Group, a relatively small group of galaxies that has a diameter of approximately one megaparsec. The Milky Way and the Andromeda Galaxy are the two brightest galaxies within the group; many of the other member galaxies are dwarf companions of these two galaxies. The Local Group itself is a part of a cloud-like structure within the Virgo Supercluster, a large, extended structure of groups and clusters of galaxies centered on the Virgo Cluster. And the Virgo Supercluster itself is a part of the Pisces-Cetus Supercluster Complex, a giant galaxy filament.

text: The Milky Way galaxy is a member of an association named the

text: Local Group

text: , a relatively small group of galaxies that has a diameter of approximately one megaparsec. The Milky Way and the Andromeda Galaxy are the two brightest galaxies within the group; many of the other member galaxies are dwarf companions of these two galaxies. The Local Group itself is a part of a cloud-like structure within the

text: Virgo Supercluster

text: , a large, extended structure of groups and clusters of galaxies centered on the

text: Virgo Cluster

text: . And the Virgo Supercluster itself is a part of the

text: Pisces-Cetus Supercluster Complex

text: , a giant

text: galaxy filament

text: Scientists study photon diffusion damping (and CMB anisotropies in general) because of the insight the subject provides into the question, "How did the universe come to be?". Specifically, primordial anisotropies in the temperature and density of the universe are supposed to be the causes of later large-scale structure formation. Thus it was the amplification of small perturbations in the pre-recombination universe that grew into the galaxies and galaxy clusters of the present era. Diffusion damping made the universe isotropic within distances on the order of the Silk Scale. That this scale corresponds to the size of observed galaxies (when the passage of time is taken into account) implies that diffusion damping is responsible for limiting the size of these galaxies. The theory is that clumps of matter in the early universe became the galaxies that we see today, and the size of these galaxies is related to the temperature and density of the clumps.

text: The Sculptor Dwarf Irregular Galaxy (SDIG) is an irregular galaxy in the constellation Sculptor.  The galaxy was discovered in 1976.

text: The Sculptor Dwarf Irregular Galaxy (SDIG) is an

text: irregular galaxy

text: in the

text: constellation

text: Sculptor

text: .  The galaxy was discovered in 1976.

text: In 2003, an overdensity of stars in the region was announced to be the Canis Major Dwarf, the closest satellite galaxy to Earth. However, there remains debate over whether it represents a disrupted dwarf galaxy or in fact a variation in the thin and thick disk and spiral arm populations of the Milky Way. Investigation of the area yielded only ten RR Lyrae variables—consistent with the Milky Way's halo and thick disk populations rather than a separate dwarf spheroidal galaxy. On the other hand, a globular cluster in Puppis, NGC 2298—which appears to be part of the Canis Major dwarf system—is extremely metal-poor, suggesting it did not arise from the Milky Way's thick disk, and instead is of extragalactic origin.

text: In 2003, an overdensity of stars in the region was announced to be the

text: Canis Major Dwarf

text: , the closest

text: satellite galaxy

text: to Earth. However, there remains debate over whether it represents a disrupted dwarf galaxy or in fact a variation in the thin and thick disk and spiral arm populations of the Milky Way. Investigation of the area yielded only ten

text: RR Lyrae variable

text: s—consistent with the

text: Milky Way's halo

text: and thick disk populations rather than a separate dwarf spheroidal galaxy. On the other hand, a

text: globular cluster

text: in Puppis,

text: NGC 2298

text: —which appears to be part of the Canis Major dwarf system—is extremely metal-poor, suggesting it did not arise from the Milky Way's thick disk, and instead is of extragalactic origin.

text: Nothing in space stands still—more precisely, standing still is meaningless without defining what "still" means. Most galaxies have been moving away ever since the Big Bang, as explained by the metric expansion of space. Galaxy motion is also influenced by galaxy groups and clusters. Stars orbit moving galaxies, and they also orbit moving star clusters and companion stars. Planets orbit their moving stars.

text: Nothing in space stands still—more precisely, standing still is meaningless without defining what "still" means. Most

text: galaxies

text: have been moving away ever since the

text: Big Bang

text: , as explained by the

text: metric expansion of space

text: . Galaxy motion is also influenced by

text: galaxy groups and clusters

text: . Stars orbit moving galaxies, and they also orbit moving

text: star cluster

text: s and

text: companion star

text: s. Planets orbit their moving stars.

text: Together with irregular galaxies, spiral galaxies make up approximately 60% of galaxies in the local Universe. They are mostly found in low-density regions and are rare in the centers of galaxy clusters.

text: Together with

text: irregular galaxies

text: , spiral galaxies make up approximately 60% of galaxies in the local

text: Universe

text: . They are mostly found in low-density regions and are rare in the centers of galaxy clusters.

text: NGC 5371 is a face-on spiral galaxy in the constellation Canes Venatici.  NGC 5371 (which also seems to be known as NGC 5390) is a symmetrical face-on Sbc barred spiral galaxy at a distance of 100 million light years.  This galaxy with Hickson Galaxy Group 68 makes up the Big Lick Galaxy Group.

text: NGC 5371 is a face-on

text: spiral galaxy

text: in the

text: constellation

text: Canes Venatici

text: .  NGC 5371 (which also seems to be known as NGC 5390) is a symmetrical face-on Sbc

text: barred spiral galaxy

text: at a distance of 100 million light years.  This galaxy with Hickson Galaxy Group 68 makes up the Big Lick Galaxy Group.

text: Grebel's research is focused on the stars of the Milky Way galaxy and other members of the local group of galaxies, including the Large and Small Magellanic Clouds as well as nearby dwarf galaxies. Grebel's studies concern the chemical evolution and structure of galaxies, star formation and the properties of the various stellar populations, with the aim of reconstructing the origin and evolution of the Milky Way and other galaxies.

text: Grebel's research is focused on the

text: star

text: s of the

text: Milky Way

text: galaxy and other members of the

text: local group

text: of galaxies, including the

text: Large

text: and

text: Small Magellanic Cloud

text: s as well as nearby

text: dwarf galaxies

text: . Grebel's studies concern the chemical evolution and structure of galaxies,

text: star formation

text: and the properties of the various

text: stellar population

text: s, with the aim of reconstructing the origin and evolution of the Milky Way and other

text: galaxies

text: The full extent of the cluster was not understood until it was more thoroughly studied in the 1950s by astronomers at Mount Palomar Observatory, although many of the individual galaxies in the cluster had been identified previously.

text: The full extent of the cluster was not understood until it was more thoroughly studied in the 1950s by astronomers at

text: Mount Palomar Observatory

text: , although many of the individual galaxies in the cluster had been identified previously.

text: UGC 6945 (also known as Arp 194) is a trio of interacting galaxies. The highly disrupted galaxy to the northwest is actually two galaxies in the advanced stages of merger, and has an angular size of . About 40″ to the southeast is a third galaxy with an angular size of .

text: UGC 6945 (also known as Arp 194) is a trio of

text: interacting galaxies

text: . The highly disrupted galaxy to the northwest is actually two galaxies in the advanced stages of merger, and has an angular size of . About 40

text: to the southeast is a third galaxy with an angular size of .

text: The galaxy is a satellite of the Milky Way and contains six globular clusters; the largest, NGC 1049, was discovered before the galaxy itself.  The galaxy is also receding from the Milky Way at 53 km/s. It mostly contains population II stars.

text: The

text: galaxy

text: is a satellite of the

text: Milky Way

text: and contains six

text: globular cluster

text: s; the largest,

text: NGC 1049

text: , was discovered before the galaxy itself.  The galaxy is also receding from the

text: Milky Way

text: at 53 km/s. It mostly contains

text: population II

text: stars.

text: Another entity called the Sun-Eater (also called "It") was first seen in Adventure Comics #352 (Jan. 1967), in a story that took place in the 30th century, the setting of the Legion of Super-Heroes, by writer Jim Shooter. To stop the colossal nimbus from ravaging the Milky Way Galaxy, the Legion recruited some of the worst criminals in the Galaxy to help them (these criminals would stay together to form the Fatal Five afterwards). But in the end, only one way to stop it was found: an "Absorbatron" bomb would have to be detonated inside its core. Only Superboy was invulnerable enough to deliver the bomb inside, but he had been weakened by radiation inside the Sun-Eater (from the red suns it had already consumed). Ferro Lad, a new addition to the Legion who possessed the power to turn into living iron, could resist going inside the Sun-Eater, but not the bomb's explosion. Heroically, he stole the bomb and delivered it anyway, killing himself and destroying the Sun-Eater, thereby saving the galaxy.

text: Another entity called the Sun-Eater (also called "It") was first seen in Adventure Comics #352 (Jan. 1967), in a story that took place in the 30th century, the setting of the

text: Legion of Super-Heroes

text: , by writer

text: Jim Shooter

text: . To stop the colossal nimbus from ravaging the

text: Milky Way

text: Galaxy, the Legion recruited some of the worst criminals in the Galaxy to help them (these criminals would stay together to form the

text: Fatal Five

text: afterwards). But in the end, only one way to stop it was found: an "Absorbatron" bomb would have to be detonated inside its core. Only

text: Superboy

text: was invulnerable enough to deliver the bomb inside, but he had been weakened by radiation inside the Sun-Eater (from the red suns it had already consumed).

text: Ferro Lad

text: , a new addition to the Legion who possessed the power to turn into living iron, could resist going inside the Sun-Eater, but not the bomb's explosion. Heroically, he stole the bomb and delivered it anyway, killing himself and destroying the Sun-Eater, thereby saving the galaxy.

text: The first recorded contact between the Imperium and the Tyranids was in 745.M41 on the Eastern Fringes of the Milky Way galaxy. There are rumors that the Ordo Xenos of the Inquisition had identified possible appearances of the Tyranids as far back as the 35th Millennium.

text: Examples of regular spiral galaxies: M31 (Andromeda Galaxy), M74, M81, M104 (Sombrero Galaxy), M51a (Whirlpool Galaxy), NGC 300, NGC 772.

text: Examples of regular spiral galaxies:

text: (Andromeda Galaxy),

text: (Sombrero Galaxy),

text: (Whirlpool Galaxy),

text: NGC 300

text: NGC 772

text: NGC 4145 is a barred spiral galaxy located in the Ursa Major galaxy cluster, 68 million light years from the Earth. The galaxy has little star formation, except on its outer edges. Due to the loss of energy that occurs without star formation, some astronomers predict that the galaxy will degenerate into a lenticular galaxy in the near future. However, the galaxy's interaction with NGC 4151 may "maintain [its] star formation".

text: NGC 4145 is a

text: barred spiral galaxy

text: located in the

text: Ursa Major galaxy cluster

text: , 68 million

text: light year

text: s from the

text: Earth

text: . The galaxy has little

text: star formation

text: , except on its outer edges. Due to the loss of energy that occurs without star formation, some astronomers predict that the galaxy will degenerate into a

text: lenticular galaxy

text: in the near future. However, the galaxy's interaction with

text: NGC 4151

text: may "maintain [its] star formation".

text: The beginning of size theory is rooted in the concept of size function, introduced by Frosini. Size functions have been initially used as a mathematical tool for shape comparison in computer vision and pattern recognition.

text: The beginning of size theory is rooted in the concept of

text: size function

text: , introduced by Frosini. Size functions have been initially used as a mathematical tool for shape comparison in

text: computer vision

text: and

text: pattern recognition

text: One of the main features of the program is its scientific accuracy. Cataloged objects are based on real data, while procedural objects are built around the cataloged universe using realistic generation algorithms. Properties of objects, such as temperature, mass, radius, etc., are presented to the user on the HUD and in an accessible information window. Users can observe objects from small spacecraft to galaxy clusters, similar to other simulators such as Celestia. SpaceEngine includes thousands of real objects, including stars from the Hipparcos catalog, galaxies from the NGC and IC catalogs, several well-known nebulae, and all known exoplanets and their stars.

text: One of the main features of the program is its scientific accuracy. Cataloged objects are based on real data, while procedural objects are built around the cataloged universe using realistic generation algorithms. Properties of objects, such as

text: temperature

text: mass

text: radius

text: , etc., are presented to the user on the

text: HUD

text: and in an accessible information window. Users can observe objects from small spacecraft to galaxy clusters, similar to other simulators such as

text: Celestia

text: . SpaceEngine includes thousands of real objects, including stars from the

text: Hipparcos

text: catalog, galaxies from the

text: NGC and IC

text: catalogs, several well-known nebulae, and all known

text: exoplanet

text: s and their stars.

text: Galaxies other than the Milky Way are popular settings for creators of science fiction, particularly those working with broad-scale space opera settings. Among the most common settings are the Andromeda Galaxy, the Magellanic Clouds, and the Triangulum Galaxy, all part of the Local Group close to the Milky Way, and in the cases of Andromeda and Triangulum the Local Group's two largest other galaxies. The difficulties involved in crossing the immense distances between galaxies are often overlooked in this type of science fiction.

text: Galaxies

text: other than the

text: Milky Way

text: are popular settings for creators of

text: science fiction

text: , particularly those working with broad-scale

text: space opera

text: settings. Among the most common settings are the

text: Andromeda Galaxy

text: , the

text: Magellanic Clouds

text: , and the

text: Triangulum Galaxy

text: , all part of the

text: Local Group

text: close to the Milky Way, and in the cases of Andromeda and Triangulum the Local Group's two largest other galaxies. The difficulties involved in crossing the immense distances between galaxies are often overlooked in this type of science fiction.

text: Stargate Atlantis is set in the dwarf galaxy Pegasus. In reality, there are two galaxies in the Local Group called Pegasus Dwarf; the Pegasus Dwarf Spheroidal Galaxy and the Pegasus Dwarf Irregular Galaxy. It has not been explicitly stated which of these is the galaxy in Stargate Atlantis. However, in this discussion regarding the new McKay-Carter Intergalactic Gate Bridge, General Hank Landry states that the distance between the Pegasus and Milky Way galaxies is "three million light-years," suggesting that the series takes place in the Pegasus Dwarf Irregular Galaxy. Also, in a few episodes the Pegasus galaxy has been seen from between the Milky Way and Pegasus, showing an irregular galaxy.

text: Stargate Atlantis

text: is set in the

text: dwarf galaxy

text: Pegasus. In reality, there are two galaxies in the

text: Local Group

text: called Pegasus Dwarf; the

text: Pegasus Dwarf Spheroidal Galaxy

text: and the

text: Pegasus Dwarf Irregular Galaxy

text: . It has not been explicitly stated which of these is the galaxy in Stargate Atlantis. However, in this discussion regarding the new

text: McKay-Carter Intergalactic Gate Bridge

text: , General

text: Hank Landry

text: states that the distance between the Pegasus and

text: Milky Way

text: galaxies is "three million light-years," suggesting that the series takes place in the Pegasus Dwarf Irregular Galaxy. Also, in a few episodes the Pegasus galaxy has been seen from between the Milky Way and Pegasus, showing an irregular galaxy.

text: Mass estimates for the Andromeda Galaxy's halo (including dark matter) give a value of approximately  (or 1.5 trillion solar masses) compared to  for the Milky Way. This contradicts earlier measurements, that seem to indicate that Andromeda Galaxy and the Milky Way are almost equal in mass. Even so, Andromeda Galaxy's spheroid actually has a higher stellar density than that of the Milky Way and its galactic stellar disk is about twice the size of that of the Milky Way. The total stellar mass of Andromeda Galaxy is estimated to be between ., (i.e., around twice as massive as that of the Milky Way) and , with around 30% of that mass in the central bulge, 56% in the disk, and the remaining 14% in the halo.

text: Mass estimates for the Andromeda Galaxy's halo (including

text: dark matter

text: ) give a value of approximately  (or 1.5

text: trillion

text: solar mass

text: es) compared to  for the Milky Way. This contradicts earlier measurements, that seem to indicate that Andromeda Galaxy and the Milky Way are almost equal in mass. Even so, Andromeda Galaxy's

text: spheroid

text: actually has a higher stellar density than that of the Milky Way and its galactic stellar disk is about twice the size of that of the Milky Way. The total stellar mass of Andromeda Galaxy is estimated to be between ., (i.e., around twice as massive as that of the Milky Way) and , with around 30% of that mass in the central

text: bulge

text: , 56% in the

text: disk

text: , and the remaining 14% in the

text: halo

text: The constellation does not lie on the galactic plane of the Milky Way, and there are no prominent star clusters. NGC 625 is a dwarf irregular galaxy of apparent magnitude 11.0 and lying some 12.7 million light years distant. Only 24000 light years in diameter, it is an outlying member of the Sculptor Group. NGC 625 is thought to have been involved in a collision and is experiencing a burst of active star formation. NGC 37 is a lenticular galaxy of apparent magnitude 14.66. It is approximately 42 kiloparsecs (137,000 light-years) in diameter and about 12.9 billion years old. Robert's Quartet (composed of the irregular galaxy NGC 87, and three spiral galaxies NGC 88, NGC 89 and NGC 92) is a group of four galaxies located around 160 million light-years away which are in the process of colliding and merging. They are within a circle of radius of 1.6 arcmin, corresponding to about 75,000 light-years. Located in the galaxy ESO 243-49 is HLX-1, an intermediate-mass black hole—the first one of its kind identified. It is thought to be a remnant of a dwarf galaxy that was absorbed in a collision with ESO 243-49. Before its discovery, this class of black hole was only hypothesized.

text: The constellation does not lie on the

text: galactic plane

text: of the Milky Way, and there are no prominent star clusters.

text: NGC 625

text: is a dwarf

text: irregular galaxy

text: of apparent magnitude 11.0 and lying some 12.7 million light years distant. Only 24000 light years in diameter, it is an outlying member of the

text: Sculptor Group

text: . NGC 625 is thought to have been involved in a collision and is experiencing a burst of

text: active star formation

text: NGC 37

text: is a

text: lenticular galaxy

text: of apparent magnitude 14.66. It is approximately 42

text: kiloparsecs

text: light-years

text: ) in diameter and about 12.9 billion years old.

text: Robert's Quartet

text: (composed of the irregular galaxy

text: NGC 87

text: , and three spiral galaxies

text: NGC 88

text: NGC 89

text: and

text: NGC 92

text: ) is a group of four galaxies located around 160 million light-years away which are in the process of colliding and merging. They are within a circle of radius of 1.6 arcmin, corresponding to about 75,000 light-years. Located in the galaxy ESO 243-49 is

text: , an

text: intermediate-mass black hole

text: —the first one of its kind identified. It is thought to be a remnant of a dwarf galaxy that was absorbed in a

text: collision

text: with ESO 243-49. Before its discovery, this class of black hole was only hypothesized.

text: According to recent studies, the Milky Way as well as the Andromeda Galaxy lie in what in the galaxy color–magnitude diagram is known as the "green valley", a region populated by galaxies in transition from the "blue cloud" (galaxies actively forming new stars) to the "red sequence" (galaxies that lack star formation). Star-formation activity in green valley galaxies is slowing as they run out of star-forming gas in the interstellar medium. In simulated galaxies with similar properties, star formation will typically have been extinguished within about five billion years from now, even accounting for the expected, short-term increase in the rate of star formation due to the collision between both the Milky Way and the Andromeda Galaxy. In fact, measurements of other galaxies similar to the Milky Way suggest it is among the reddest and brightest spiral galaxies that are still forming new stars and it is just slightly bluer than the bluest red sequence galaxies.

text: According to recent studies, the Milky Way as well as the Andromeda Galaxy lie in what in the

text: galaxy color–magnitude diagram

text: is known as the "green valley", a region populated by galaxies in transition from the "blue cloud" (galaxies actively forming new stars) to the "red sequence" (galaxies that lack star formation). Star-formation activity in green valley galaxies is slowing as they run out of star-forming gas in the interstellar medium. In simulated galaxies with similar properties, star formation will typically have been extinguished within about five billion years from now, even accounting for the expected, short-term increase in the rate of star formation due to the collision between both the Milky Way and the Andromeda Galaxy. In fact, measurements of other galaxies similar to the Milky Way suggest it is among the reddest and brightest spiral galaxies that are still forming new stars and it is just slightly bluer than the bluest red sequence galaxies.

text: A galaxy cluster, or cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity  with typical masses ranging from 10–10 solar masses. They are the largest known gravitationally bound structures in the universe and were believed to be the largest known structures in the universe until the 1980s, when superclusters were discovered. One of the key features of clusters is the intracluster medium (ICM). The ICM consists of heated gas between the galaxies and has a peak temperature between 2–15 keV that is dependent on the total mass of the cluster. Galaxy clusters should not be confused with star clusters, such as open clusters, which are structures of stars within galaxies, or with globular clusters, which typically orbit galaxies. Small aggregates of galaxies are referred to as groups of galaxies rather than clusters of galaxies. The groups and clusters can themselves cluster together to form superclusters.

text: A galaxy cluster, or cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of

text: galaxies

text: that are bound together by

text: gravity

text: with typical masses ranging from 10–10 solar masses. They are the largest known

text: gravitationally bound

text: structures in the universe and were believed to be the

text: largest known structures

text: in the universe until the 1980s, when

text: supercluster

text: s were discovered. One of the key features of clusters is the

text: intracluster medium

text: (ICM). The ICM consists of heated gas between the galaxies and has a peak temperature between 2–15 keV that is dependent on the total mass of the cluster. Galaxy clusters should not be confused with

text: star cluster

text: s, such as

text: open cluster

text: s, which are structures of stars within galaxies, or with

text: globular cluster

text: s, which typically orbit galaxies. Small aggregates of galaxies are referred to as

text: groups of galaxies

text: rather than clusters of galaxies. The

text: groups and clusters

text: can themselves cluster together to form

text: supercluster

text: s.

text: By the second day Shaeffer realizes he cannot make the trip in the four month time limit, and will be forced to pay two thousand stars for each day he exceeds that limit. He estimates it will take him six months to complete the trip, forfeiting about 120,000 stars and leaving him in about the same state of near insolvency he is in now. However, he suddenly realizes that if he can make some of the trip to the core between spiral arms of the galaxy where the stars are far apart, he will not have to dodge stars quite as frequently. He requests this information and one of the Puppeteer’s assistants provides him with a course to exit the spiral arm. In three weeks’ time he travels to the end of the gap and begins to enter the central portion of the galaxy.

text: Andromeda is approximately 220,000 light years across, and it is the largest galaxy of the Local Group, which also contains the Milky Way, the Triangulum Galaxy, and other smaller galaxies. Despite earlier findings that suggested that the Milky Way contains more dark matter and could be the largest in the grouping, the 2006 observations by the Spitzer Space Telescope revealed that Andromeda contains one trillion (10) stars: at least twice the number of stars in the Milky Way, which is estimated to be 200–400 billion. The mass of the Andromeda Galaxy is estimated to be 1.5 solar masses, while the Milky Way is estimated to be 8.5 solar masses.

text: Andromeda is approximately 220,000 light years across, and it is the largest galaxy of the

text: Local Group

text: , which also contains the Milky Way, the

text: Triangulum Galaxy

text: , and other smaller galaxies. Despite earlier findings that suggested that the Milky Way contains more

text: dark matter

text: and could be the largest in the grouping, the 2006 observations by the

text: Spitzer Space Telescope

text: revealed that Andromeda contains

text: one trillion (10)

text: stars: at least twice the number of stars in the Milky Way, which is estimated to be 200–400 billion. The mass of the Andromeda Galaxy is estimated to be 1.5

text: solar mass

text: es, while the Milky Way is estimated to be 8.5 solar masses.

text: Boötes III is an overdensity in the Milky Way's halo, which may be a disrupted dwarf spheroidal galaxy. It is situated in the constellation Boötes and was discovered in 2009 in the data obtained by Sloan Digital Sky Survey. The galaxy is located at the distance of about 46 kpc from the Sun and moves away the Sun with the speed of about 200 km/s. It has an elongated shape (axis ratio of 2:1) with the radius of about 0.5 kpc. The large size and an irregular shape may indicate that Bootes III in a transitional phase between a gravitationally bound galaxy and completely unbound system.

text: Boötes III is an overdensity in the Milky Way's

text: halo

text: , which may be a disrupted

text: dwarf spheroidal galaxy

text: . It is situated in the constellation

text: Boötes

text: and was discovered in 2009 in the data obtained by

text: Sloan Digital Sky Survey

text: . The galaxy is located at the distance of about 46 kpc from the

text: Sun

text: and moves away the Sun with the speed of about 200 km/s. It has an elongated shape (axis ratio of 2:1) with the radius of about 0.5 kpc. The large size and an irregular shape may indicate that Bootes III in a transitional phase between a gravitationally bound galaxy and completely unbound system.

text: Thus for a spherical galaxy with a equal to b, the numberis 0, and the Hubble type is E0. The limit is about E7, which is believed to be due to a bending instability that causes flatter galaxies to puff up. The most common shape is close to E3.  Hubble recognized that his shape classification depends both on the intrinsic shape of the galaxy, as well as the angle with which the galaxy is observed.  Hence, some galaxies with Hubble type E0 are actually elongated.

text: Thus for a spherical galaxy with a equal to b, the numberis 0, and the Hubble type is E0. The limit is about E7, which is believed to be due to a

text: bending instability

text: that causes flatter galaxies to puff up. The most common shape is close to E3.  Hubble recognized that his shape classification depends both on the intrinsic shape of the galaxy, as well as the angle with which the galaxy is observed.  Hence, some galaxies with Hubble type E0 are actually elongated.

text: Stone also pushed the boundaries of the ascended masters teachings by channeling entities dwelling farther out in our galaxy than any other medium had ever attempted to do before.  He formulated a chart he called the "Cosmic Map", in which he, for the first time ever for any ascended master teachings teacher, detailed the structure of the ascended master hierarchy within the Milky Way Galaxy.  According to writings of Joshua David Stone, this sector of the Milky Way Galaxy—one twelfth of the total volume of the galactic disc—is governed by a cosmic being (Elizabeth Clare Prophet's term—Stone himself uses the term cosmic master instead of cosmic being to denote ascended masters of extraterrestrial origin) named Melchior working out of the constellation of the Great Bear (Alice A. Bailey stated that each of the Seven Rays is focused from the center of the galaxy through one of the seven stars of the Big Dipper).  Working with "Melchior" on the governing council of this sector of the galaxy operating from Ursa Major is said to be the [Local galactic sector] cosmic being Melchizedek (not the same being as the terrestrial Master Melchizedek, said by Elizabeth Clare Prophet to be the ascended master that the Biblical Melchizedek became after his death [ascension] on Earth). According to Joshua David Stone, there is a powerful cosmic being functioning at the galactic core of the Milky Way Galaxy named Averran, whom he identified as the governing deity of the Milky Way Galaxy and thus the personification in the ascended master teachings of what in conventional Theosophy is called the Galactic Logos.  Working with Averran at the galactic core under his authority are said to be the cosmic beings Vywamus, Lenduce, Adonis and  Atlanto.

text: Stone also pushed the boundaries of the ascended masters teachings by

text: channeling

text: entities dwelling farther out in our

text: galaxy

text: than any other

text: medium

text: had ever attempted to do before.  He formulated a chart he called the "Cosmic Map", in which he, for the first time ever for any ascended master teachings teacher, detailed the structure of the

text: ascended master hierarchy

text: within the

text: Milky Way Galaxy

text: .  According to writings of Joshua David Stone, this sector of the Milky Way Galaxy—one twelfth of the total volume of the

text: galactic disc

text: —is governed by a

text: cosmic being

text: Elizabeth Clare Prophet

text: 's term—Stone himself uses the term cosmic master instead of cosmic being to denote ascended masters of

text: extraterrestrial

text: origin) named Melchior working out of the

text: constellation

text: of the

text: Great Bear

text: Alice A. Bailey

text: stated that each of the

text: Seven Rays

text: is focused from the center of the galaxy through one of the seven

text: star

text: s of the

text: Big Dipper

text: ).  Working with "Melchior" on the governing council of this sector of the galaxy operating from Ursa Major is said to be the [Local galactic sector] cosmic being Melchizedek (not the same being as the terrestrial Master Melchizedek, said by Elizabeth Clare Prophet to be the ascended master that the

text: Biblical

text: Melchizedek

text: became after his death [ascension] on Earth). According to Joshua David Stone, there is a powerful cosmic being functioning at the

text: galactic core

text: of the Milky Way Galaxy named Averran, whom he identified as the governing

text: deity

text: of the Milky Way Galaxy and thus the personification in the ascended master teachings of what in conventional

text: Theosophy

text: is called the

entity_section: Cosmic beings governing the Milky Way Galaxy from the galactic core

text: Galactic Logos

text: .  Working with Averran at the galactic core under his authority are said to be the cosmic beings Vywamus, Lenduce, Adonis and  Atlanto.

text: The Dorado Group contains three dominant smaller groups within itself, NGC 1672 Group, NGC 1566 Group and the NGC 1433 Group, as evidenced by the H I distribution of the region. The Dorado Group is in the Fornax Wall that connects these three groups. Duento its location in the Fornax Wall, the group is at a similar distance as the Fornax Cluster.  The Dorado Group is richer than the Local Group, while still being dominated by disk types of galaxies (i.e. its two brightest members are spiral NGC 1566 and lenticular NGC 1553) and its member galaxies have H I masses on par with non-interacting galaxies of the same morphological type.  With the group's apparent crossing time being 12.6 ± 0.6 % of the universe's age, recent analyses deduce that the group is unvirialized, and thus this may explain the abundance of spirals and H I.

text: The Dorado Group contains three dominant smaller groups within itself,

text: NGC 1672 Group

text: NGC 1566 Group

text: and the

text: NGC 1433 Group

text: , as evidenced by the

text: H I

text: distribution of the region. The Dorado Group is in the

text: Fornax Wall

text: that connects these three groups. Duento its location in the Fornax Wall, the group is at a similar distance as the

text: Fornax Cluster

text: .  The Dorado Group is richer than the

text: Local Group

text: , while still being dominated by disk

text: types of galaxies

text: (i.e. its two brightest members are spiral NGC 1566 and lenticular NGC 1553) and its member galaxies have H I masses on par with

text: non-interacting galaxies

text: of the same morphological type.  With the group's apparent crossing time being 12.6 ± 0.6 % of the

text: universe's age

text: , recent analyses deduce that the group is

text: unvirialized

text: , and thus this may explain the abundance of spirals and H I.

text: Adjacent to the Omega Octant of the Milky Way Galaxy, the Iridani Cluster is home to one rather adventurous space-faring race presented in the SFB Omega-series modules...

text: Size and geometry also plays a role in determining the shape of the R curve. A crack in a thin sheet tends to produce a steeper R curve than a crack in a thick plate because there is a low degree of stress triaxiality at the crack tip in the thin sheet while the material near the tip of the crack in the thick plate may be in plane strain. The R curve can also change at free boundaries in the structure. Thus, a wide plate may exhibit a somewhat different crack growth resistance behavior than a narrow plate of the same material. Ideally, the R curve, as well as other measures of fracture toughness, is a property only of the material and does not depend on the size or shape of the cracked body. Much of fracture mechanics is predicated on the assumption that fracture toughness is a material property.

text: Size and geometry also plays a role in determining the shape of the R curve. A crack in a thin sheet tends to produce a steeper R curve than a crack in a thick plate because there is a low degree of stress triaxiality at the crack tip in the thin sheet while the material near the tip of the crack in the thick plate may be in plane strain. The R curve can also change at free boundaries in the structure. Thus, a wide plate may exhibit a somewhat different crack growth resistance behavior than a narrow plate of the same material. Ideally, the R curve, as well as other measures of fracture toughness, is a property only of the material and does not depend on the size or shape of the cracked body. Much of

text: fracture mechanics

text: is predicated on the assumption that

text: fracture toughness

text: is a material property.

text: Galaxy mergers can occur when two (or more) galaxies collide.  They are the most violent type of galaxy interaction. Although galaxy mergers do not involve stars or star systems actually colliding, due to the vast distances between stars in most circumstances, the gravitational interactions between galaxies and the friction between the gas and dust have major effects on the galaxies involved.  The exact effects of such mergers depend on a wide variety of parameters such as collision angles, speeds, and relative size/composition, and are currently an extremely active area of research. Galaxy mergers are important because the merger rate is fundamental measurement of galaxy evolution. The merger rate also provides astronomers with clues about how galaxies bulked up over time.

text: Galaxy mergers can occur when two (or more)

text: galaxies

text: collide.  They are the most violent type of

text: galaxy interaction

text: . Although galaxy mergers do not involve

text: star

text: s or star systems actually colliding, due to the vast distances between stars in most circumstances, the

text: gravitational interactions

text: between galaxies and the friction between the

text: gas

text: and

text: dust

text: have major effects on the galaxies involved.  The exact effects of such mergers depend on a wide variety of parameters such as

text: collision

text: angles,

text: speed

text: s, and relative size/composition, and are currently an extremely active area of research. Galaxy mergers are important because the merger rate is fundamental measurement of

text: galaxy evolution

text: . The merger rate also provides astronomers with clues about how galaxies bulked up over time.

text: The kinematics of disk galaxies are usually determined by Hα or 21-cm emission lines, which are typically not present in lenticular galaxies due to their general lack of cool gas. Thus kinematic information and rough mass estimates for lenticular galaxies often comes from stellar absorption lines, which are less reliable than emission line measurements. There is also a considerable amount of difficulty in deriving accurate rotational velocities for lenticular galaxies. This is a combined effect from lenticulars having difficult inclination measurements, projection effects in the bulge-disk interface region, and the random motions of stars affecting the true rotational velocities. These effects make kinematic measurements of lenticular galaxies considerably more difficult compared to normal disk galaxies.

text: The kinematics of disk galaxies are usually determined by

text: Hα

text: or

text: emission lines, which are typically not present in lenticular galaxies due to their general lack of cool gas. Thus kinematic information and rough mass estimates for lenticular galaxies often comes from stellar absorption lines, which are less reliable than emission line measurements. There is also a considerable amount of difficulty in deriving accurate rotational velocities for lenticular galaxies. This is a combined effect from lenticulars having difficult inclination measurements, projection effects in the bulge-disk interface region, and the random motions of stars affecting the true rotational velocities. These effects make kinematic measurements of lenticular galaxies considerably more difficult compared to normal disk galaxies.

text: In January 2006, researchers reported that the heretofore unexplained warp in the disk of the Milky Way has now been mapped and found to be a ripple or vibration set up by the Large and Small Magellanic Clouds as they orbit the Milky Way, causing vibrations when they pass through its edges. Previously, these two galaxies, at around 2% of the mass of the Milky Way, were considered too small to influence the Milky Way. However, in a computer model, the movement of these two galaxies creates a dark matter wake that amplifies their influence on the larger Milky Way.

text: Many stars visible to the naked eye have such a low absolute magnitude that they would appear bright enough to cast shadows if they were at 10 parsecs from the Earth: Rigel (−7.0), Deneb (−7.2), Naos (−6.0), and Betelgeuse (−5.6). For comparison, Sirius has an absolute magnitude of 1.4, which is brighter than the Sun, whose absolute visual magnitude is 4.83 (it actually serves as a reference point). The Sun's absolute bolometric magnitude is set arbitrarily, usually at 4.75.Absolute magnitudes of stars generally range from −10 to +17. The absolute magnitudes of galaxies can be much lower (brighter). For example, the giant elliptical galaxy M87 has an absolute magnitude of −22 (i.e. as bright as about 60,000 stars of magnitude −10).

text: Many stars visible to the naked eye have such a low absolute magnitude that they would appear bright enough to cast shadows if they were at 10 parsecs from the Earth:

text: Rigel

text: Deneb

text: Naos

text: (−6.0), and

text: Betelgeuse

text: (−5.6). For comparison,

text: Sirius

text: has an absolute magnitude of 1.4, which is brighter than the

text: Sun

text: , whose absolute visual magnitude is

text: (it actually serves as a reference point). The Sun's absolute bolometric magnitude is set arbitrarily, usually at 4.75.Absolute magnitudes of stars generally range from −10 to +17. The absolute magnitudes of galaxies can be much lower (brighter). For example, the giant

text: elliptical galaxy M87

text: has an absolute magnitude of −22 (i.e. as bright as about 60,000 stars of magnitude −10).

text: MACS1149-JD (also known as PCB2012 3020)  is a one the farthest known galaxies from Earth and is at redshift of about z=9.6 or 13.2 billion light-years away. It is 1 percent of the Milky Way's mass.

text: MACS1149-JD (also known as PCB2012 3020)  is a one the farthest known

text: galaxies

text: from

text: Earth

text: and is at

text: redshift

text: of about z=9.6 or 13.2 billion

text: light-year

text: s away. It is 1 percent of the

text: Milky Way

text: 's mass.

text: While precise fitting of the bulge, disk, and halo density profiles is a rather complicated process, it is straightforward to model the observables of rotating galaxies through this relationship. So, while state-of-the-art cosmological and galaxy formation simulations of dark matter with normal baryonic matter included can be matched to galaxy observations, there is not yet any straightforward explanation as to why the observed scaling relationship exists. Additionally, detailed investigations of the rotation curves of low-surface-brightness galaxies (LSB galaxies) in the 1990s and of their position on the Tully–Fisher relation showed that LSB galaxies had to have dark matter haloes that are more extended and less dense than those of HSB galaxies and thus surface brightness is related to the halo properties. Such dark-matter-dominated dwarf galaxies may hold the key to solving the dwarf galaxy problem of structure formation.

text: While precise fitting of the bulge, disk, and halo density profiles is a rather complicated process, it is straightforward to model the observables of rotating galaxies through this relationship. So, while state-of-the-art cosmological and

text: galaxy formation

text: simulations of dark matter with normal

text: baryonic

text: matter included can be matched to galaxy observations, there is not yet any straightforward explanation as to why the observed scaling relationship exists. Additionally, detailed investigations of the rotation curves of

text: low-surface-brightness galaxies

text: (LSB galaxies) in the 1990s and of their position on the Tully–Fisher relation showed that LSB galaxies had to have

text: dark matter halo

text: es that are more extended and less dense than those of HSB galaxies and thus surface brightness is related to the halo properties. Such dark-matter-dominated

text: dwarf galaxies

text: may hold the key to solving the

text: dwarf galaxy problem

text: of

text: structure formation

text: CL 0024+1654 is a massive galaxy cluster that lenses the galaxy behind it, creating arc-shaped images of the background galaxy. The cluster is primarily made up of yellow elliptical and spiral galaxies, at a distance of 3.6 billion light-years from Earth (redshift 0.4), half as far away as the background galaxy, which is at a distance of 5.7 billion light-years (redshift 1.67).

text: CL 0024+1654

text: is a massive

text: galaxy cluster

text: that

text: lenses

text: the galaxy behind it, creating arc-shaped images of the background galaxy. The cluster is primarily made up of yellow

text: elliptical

text: and spiral galaxies, at a distance of 3.6 billion light-years from Earth (redshift 0.4), half as far away as the background galaxy, which is at a distance of 5.7 billion light-years (redshift 1.67).

text: Arp 116 (APG 116) is a pair of interacting galaxies composed of elliptical galaxy Messier 60 and spiral galaxy NGC 4647, located in the Virgo Constellation, lying about 60 million light years away, in the Virgo Cluster, at right ascension  declination . Interaction between the two galaxies has just begun, with initial findings of tidal interaction being found in 2012. With an apparent separation between the galaxies of 2'.5, the optical discs of the two galaxies overlap.

text: Arp 116 (

text: APG

text: 116) is a

text: pair

text: of

text: interacting

text: galaxies

text: composed of

text: elliptical galaxy

text: Messier 60

text: and

text: spiral galaxy

text: NGC 4647

text: , located in the

text: Virgo Constellation

text: , lying about 60 million

text: light year

text: s away, in the

text: Virgo Cluster

text: , at

text: right ascension

text: declination

text: . Interaction between the two galaxies has just begun, with initial findings of tidal interaction being found in 2012. With an apparent separation between the galaxies of 2'.5, the optical discs of the two galaxies overlap.

text: NGC 5195 and the Whirlpool Galaxy comprise one of the most noted interacting galaxy pairs in astronomy.  The two galaxies are listed in the Atlas of Peculiar Galaxies as one of several prominent examples of a spiral galaxy with a companion galaxy. The system was also the subject of very early theoretical investigations into galaxy interactions.  The two galaxies are connected by a dust-rich tidal bridge. The dust in this tidal bridge can be seen silhouetted against the center of NGC 5195.  This demonstrates that NGC 5195 appears to lie behind the Whirlpool Galaxy.  The encounter has significantly enhanced the spiral structure of M51.

text: NGC 5195 and the Whirlpool Galaxy comprise one of the most noted interacting galaxy pairs in astronomy.  The two galaxies are listed in the

text: Atlas of Peculiar Galaxies

text: as one of several prominent examples of a spiral galaxy with a companion galaxy. The system was also the subject of very early theoretical investigations into galaxy interactions.  The two galaxies are connected by a dust-rich tidal bridge. The dust in this tidal bridge can be seen silhouetted against the center of NGC 5195.  This demonstrates that NGC 5195 appears to lie behind the Whirlpool Galaxy.  The encounter has significantly enhanced the spiral structure of M51.

text: An unbarred spiral galaxy is a type of spiral galaxy without a central bar, or one that is not a barred spiral galaxy.  It is designated with an SA in the galaxy morphological classification scheme.

text: An unbarred spiral galaxy is a type of

text: spiral galaxy

text: without a central bar, or one that is not a

text: barred spiral galaxy

text: .  It is designated with an SA in the

text: galaxy morphological classification

text: scheme.

text: It is a binary system together with the bright spiral galaxy M77 (NGC 1068). These two are the largest galaxies of a small galaxy group that also includes NGC 1073, and five other small irregular galaxies.

text: It is a binary system together with the bright spiral galaxy

text: M77 (NGC 1068)

text: . These two are the largest galaxies of a small galaxy group that also includes

text: NGC 1073

text: , and five other small irregular galaxies.

text: The hyperspace travel in the Star Wars franchise requires two elements, light speed travel and Hyperspace. Ships in the Star Wars Universe have engines capable of propelling them to the speed of light. However, current physical theory states that it is impossible for any physical object to attain that speed, as long as the object has a non-zero mass. Doing so would require infinite energy, which is also impossible to generate in our universe. Even if one was traveling at the speed of light, it would still take thousands of years to travel the galaxy, unless the galaxy is smaller in size, possibly the case in Star Wars; therefore the Star Wars ships use a "hyperdrive".

text: The hyperspace travel in the Star Wars franchise requires two elements,

text: light speed travel

text: and

text: Hyperspace

text: . Ships in the Star Wars Universe have engines capable of propelling them to the speed of light. However, current physical theory states that it is impossible for any physical object to attain that speed, as long as the object has a non-zero

text: mass

text: . Doing so would require infinite energy, which is also impossible to generate in our universe. Even if one was traveling at the speed of light, it would still take thousands of years to travel the galaxy, unless the galaxy is smaller in size, possibly the case in Star Wars; therefore the Star Wars ships use a "

text: hyperdrive

text: The Avengers - at microscopic size compared to the entity - breach its head and attempt to reach the brain to learn more and possibly neutralize it. As the Avengers battle more of the same robots within the entity, Tigra watches as it shapes the molten ore into a cylinder. Several more beings, of the same size and scope, also arrive bearing similar cylinders, which Tigra assumes are former planets. The group fuses with the cylinders to form a huge circular ring that clamps the star close to the original planet the Avengers visited.Another spatial rift opens and an even larger hand appears and begins to drag away the entire galaxy.

text: The Avengers - at

text: microscopic

text: size compared to the entity - breach its head and attempt to reach the

text: brain

text: to learn more and possibly neutralize it. As the Avengers battle more of the same robots within the entity, Tigra watches as it shapes the molten ore into a

text: cylinder

text: . Several more beings, of the same size and scope, also arrive bearing similar cylinders, which Tigra assumes are former planets. The group fuses with the cylinders to form a huge circular ring that clamps the

text: star

text: close to the original planet the Avengers visited.Another spatial rift opens and an even larger hand appears and begins to drag away the entire

text: galaxy

text: cD galaxies are believed to grow via mergers of galaxies that spiral in to the center of a galaxy cluster, a theory first proposed by Herbert J. Rood in 1965. This "cannibalistic" mode of growth leads to the large diameter and luminosity of the cD's. The second-brightest galaxy in the cluster is usually under-luminous, a consequence of its having been "eaten".  Remains of "eaten" galaxies sometimes appear as a diffuse halo of gas and dust. This halo can be up to 3 million light years in diameter. It is estimated that the cD galaxy alone contributes 1-7%, depending on the cluster mass, of the total baryon mass within 12.5 virial radii.

text: cD galaxies are believed to grow via mergers of galaxies that spiral in to the center of a galaxy cluster, a theory first proposed by Herbert J. Rood in 1965. This "

text: cannibalistic

text: " mode of growth leads to the large diameter and luminosity of the cD's. The second-brightest galaxy in the cluster is usually under-luminous, a consequence of its having been "eaten".  Remains of "eaten" galaxies sometimes appear as a diffuse halo of

text: gas

text: and

text: dust

text: . This halo can be up to 3 million light years in diameter. It is estimated that the cD galaxy alone contributes 1-7%, depending on the cluster mass, of the total

text: baryon

text: mass within 12.5

text: virial radii

text: The trophy was created by artist Olafur Eliasson. Like much of Eliasson's work, the sculpture explores the common ground between art and science. It is molded into the shape of a toroid, recalling natural forms found from black holes and galaxies to seashells and coils of DNA.

text: The trophy was created by artist

text: Olafur Eliasson

text: . Like much of Eliasson's work, the sculpture explores the common ground between art and science. It is molded into the shape of a

text: toroid

text: , recalling natural forms found from black holes and galaxies to seashells and coils of DNA.

text: Current theory is divided on whether the first stars were very massive or not - theories proposed in 2009 and 2011 suggest the first star groups might have consisted of a massive star surrounded by several smaller stars. One theory, which seems to be borne out by computer models of star formation, is that with no heavy elements and a much warmer interstellar medium from the Big Bang, it was easy to form stars with much greater total mass than the ones visible today. Typical masses for population III stars are expected to be about several hundred solar masses, which is much larger than that of current stars. Analysis of data of extremely low-metallicity population II stars such as HE0107-5240, which are thought to contain the metals produced by population III stars, suggest that these metal-free stars had masses of 20 to 130 solar masses. On the other hand, analysis of globular clusters associated with elliptical galaxies suggests pair-instability supernovae, which are typically associated with very massive stars, were responsible for their metallic composition. This also explains why there have been no low-mass stars with zero metallicity observed, although models have been constructed for smaller population III stars. Clusters containing zero-metallicity red dwarfs or brown dwarfs (possibly created by pair-instability supernovae) have been proposed as dark matter candidates, but searches for these and other MACHOs through gravitational microlensing have produced negative results.

text: Current theory is divided on whether the first stars were very massive or not - theories proposed in 2009 and 2011 suggest the first star groups might have consisted of a massive star surrounded by several smaller stars. One theory, which seems to be borne out by computer models of

text: star formation

text: , is that with no heavy elements and a much warmer

text: interstellar medium

text: from the Big Bang, it was easy to form stars with much greater total mass than the ones visible today. Typical masses for population III stars are expected to be about several hundred

text: solar mass

text: es, which is much larger than that of current stars. Analysis of data of extremely low-

text: metallicity

text: population II stars such as

text: , which are thought to contain the metals produced by population III stars, suggest that these metal-free stars had masses of 20 to 130 solar masses. On the other hand, analysis of

text: globular cluster

text: s associated with

text: elliptical galaxies

text: suggests

text: pair-instability supernova

text: e, which are typically associated with very massive stars, were responsible for their

text: metallic

text: composition. This also explains why there have been no low-mass stars with zero

text: metallicity

text: observed, although models have been constructed for smaller population III stars. Clusters containing zero-metallicity

text: red dwarfs

text: or

text: brown dwarfs

text: (possibly created by pair-instability supernovae) have been proposed as

text: dark matter

text: candidates, but searches for these and other

text: MACHO

text: s through

text: gravitational microlensing

text: have produced negative results.

text: The primary goal of the catalog was to present photographs of examples of the different kinds of peculiar structures found among nearby galaxies. Arp realized that the reason why galaxies formed into spiral or elliptical shapes was not well understood. He perceived peculiar galaxies as small "experiments" that astronomers could use to understand the physical processes that distort spiral or elliptical galaxies. With this atlas, astronomers had a sample of peculiar galaxies that they could study in more detail. The atlas does not present a complete overview of every peculiar galaxy in the sky but instead provides examples of the different phenomena as observed in nearby galaxies.

text: The primary goal of the catalog was to present

text: photographs

text: of examples of the different kinds of peculiar structures found among nearby galaxies. Arp realized that the reason why galaxies formed into

text: spiral

text: or

text: elliptical

text: shapes was not well understood. He perceived peculiar galaxies as small "experiments" that astronomers could use to understand the physical processes that distort spiral or elliptical galaxies. With this atlas, astronomers had a sample of peculiar galaxies that they could study in more detail. The atlas does not present a complete overview of every peculiar galaxy in the sky but instead provides examples of the different phenomena as observed in nearby galaxies.

text: In the 1960-1970s, research to further understand the properties of Seyfert galaxies was carried out. A few direct measurements of the actual sizes of Seyfert nuclei were taken, and it was established that the emission lines in NGC 1068 were produced in a region over a thousand light years in diameter. Controversy existed over whether Seyfert redshifts were of cosmological origin. Confirming estimates of the distance to Seyfert galaxies and their age were limited since their nuclei vary in brightness over a time scale of a few years; therefore arguments involving distance to such galaxies and the constant speed of light cannot always be used to determine their age. In the same time period, research had been undertaken to survey, identify and catalogue galaxies, including Seyferts. Beginning in 1967, Benjamin Markarian published lists containing a few hundred galaxies distinguished by their very strong ultraviolet emission, with measurements on the position of some of them being improved in 1973 by other researchers. At the time, it was believed that 1% of spiral galaxies are Seyferts. By 1977, it was found that very few Seyfert galaxies are ellipticals, most of them being normal or barred spiral galaxies. During the same time period, efforts have been made to gather spectrophotometric data for Seyfert galaxies. It became obvious that not all spectra from Seyfert galaxies look the same, so they have been subclassified according to the characteristics of their emission spectra. A simple division into types I and II has been devised, with the classes depending on the relative width of their emission lines. It has been later noticed that some Seyfert nuclei show intermediate properties, resulting in their being further subclassified into types 1.2, 1.5, 1.8 and 1.9 (see Classification). Early surveys for Seyfert galaxies were biased in counting only the brightest representatives of this group. More recent surveys that count galaxies with low-luminosity and obscured Seyfert nuclei suggest that the Seyfert phenomenon is actually quite common, occurring in 16% ± 5% of galaxies; indeed, several dozen galaxies exhibiting the Seyfert phenomenon exist in the close vicinity (≈27 Mpc) of our own galaxy. Seyfert galaxies form a substantial fraction of the galaxies appearing in the Markarian catalog, a list of galaxies displaying an ultraviolet excess in their nuclei.

text: In the 1960-1970s, research to further understand the properties of Seyfert galaxies was carried out. A few direct measurements of the actual sizes of Seyfert nuclei were taken, and it was established that the emission lines in NGC 1068 were produced in a region over a thousand light years in diameter. Controversy existed over whether Seyfert redshifts were of cosmological origin. Confirming estimates of the distance to Seyfert galaxies and their age were limited since their nuclei vary in brightness over a time scale of a few years; therefore arguments involving distance to such galaxies and the constant speed of light cannot always be used to determine their age. In the same time period, research had been undertaken to survey, identify and catalogue galaxies, including Seyferts. Beginning in 1967,

text: Benjamin Markarian

text: published lists containing a few hundred galaxies distinguished by their very strong ultraviolet emission, with measurements on the position of some of them being improved in 1973 by other researchers. At the time, it was believed that 1% of spiral galaxies are Seyferts. By 1977, it was found that very few Seyfert galaxies are ellipticals, most of them being normal or barred spiral galaxies. During the same time period, efforts have been made to gather

text: spectrophotometric

text: data for Seyfert galaxies. It became obvious that not all spectra from Seyfert galaxies look the same, so they have been subclassified according to the characteristics of their

text: emission spectra

text: . A simple division into types I and II has been devised, with the classes depending on the relative width of their

text: emission lines

text: . It has been later noticed that some Seyfert nuclei show intermediate properties, resulting in their being further subclassified into types 1.2, 1.5, 1.8 and 1.9 (see

text: Classification

text: ). Early surveys for Seyfert galaxies were biased in counting only the brightest representatives of this group. More recent surveys that count galaxies with low-luminosity and obscured Seyfert nuclei suggest that the Seyfert phenomenon is actually quite common, occurring in 16% ± 5% of galaxies; indeed, several dozen galaxies exhibiting the Seyfert phenomenon exist in the close vicinity (≈27 Mpc) of our own galaxy. Seyfert galaxies form a substantial fraction of the galaxies appearing in the

text: Markarian catalog

text: , a list of galaxies displaying an ultraviolet excess in their nuclei.

text: NGC 3982 is a Seyfert 2 galaxy that spans about 30,000 light-years, about one-third of the size of our Milky Way galaxy. The galaxy is receding from us at about 1109 km/s. The galaxy is a typical spiral galaxy, similar to our Milky Way. It harbors a supermassive black hole at its core and has massive regions of star formation in the bright blue knots in the spiral arms. Supernovae are likely to be found within these regions.

text: NGC 3982 is a

text: Seyfert 2 galaxy

text: that spans about 30,000 light-years, about one-third of the size of our

text: Milky Way

text: galaxy. The galaxy is receding from us at about 1109 km/s. The galaxy is a typical spiral galaxy, similar to our Milky Way. It harbors a supermassive black hole at its core and has massive regions of star formation in the bright blue knots in the spiral arms. Supernovae are likely to be found within these regions.

text: Ages for star clusters can be estimated by comparing the Hertzsprung-Russell diagram for the cluster with theoretical models of stellar evolution. Using this technique, ages for the Pleiades of between 75 and 150 million years have been estimated. The wide spread in estimated ages is a result of uncertainties in stellar evolution models, which include factors such as convective overshoot, in which a convective zone within a star penetrates an otherwise non-convective zone, resulting in higher apparent ages.

text: Ages for star clusters can be estimated by comparing the

text: Hertzsprung-Russell diagram

text: for the cluster with theoretical models of

text: stellar evolution

text: . Using this technique, ages for the Pleiades of between 75 and 150 million years have been estimated. The wide spread in estimated ages is a result of uncertainties in stellar evolution models, which include factors such as

text: convective overshoot

text: , in which a

text: convective

text: zone within a star penetrates an otherwise non-convective zone, resulting in higher apparent ages.

text: Galaxies that do not fit into the Hubble sequence, because they have no regular structure (either disk-like or ellipsoidal), are termed irregular galaxies. Hubble defined two classes of irregular galaxy:

text: Galaxies that do not fit into the Hubble sequence, because they have no regular structure (either disk-like or ellipsoidal), are termed

text: irregular galaxies

text: . Hubble defined two classes of irregular galaxy:

text: In the 1910s, Vesto Slipher (and later Carl Wilhelm Wirtz) interpreted the red shift of spiral nebulae as a Doppler shift that indicated they were receding from Earth. However, it is difficult to determine the distance to astronomical objects. One way is to compare the physical size of an object to its angular size, but a physical size must be assumed to do this. Another method is to measure the brightness of an object and assume an intrinsic luminosity, from which the distance may be determined using the inverse square law. Due to the difficulty of using these methods, they did not realize that the nebulae were actually galaxies outside our own Milky Way, nor did they speculate about the cosmological implications. In 1927, the Belgian Roman Catholic priest Georges Lemaître independently derived the Friedmann–Lemaître–Robertson–Walker equations and proposed, on the basis of the recession of spiral nebulae, that the universe began with the "explosion" of a "primeval atom"—which was later called the Big Bang. In 1929, Edwin Hubble provided an observational basis for Lemaître's theory. Hubble showed that the spiral nebulae were galaxies by determining their distances using measurements of the brightness of Cepheid variable stars. He discovered a relationship between the redshift of a galaxy and its distance. He interpreted this as evidence that the galaxies are receding from Earth in every direction at speeds proportional to their distance. This fact is now known as Hubble's law, though the numerical factor Hubble found relating recessional velocity and distance was off by a factor of ten, due to not knowing about the types of Cepheid variables.

text: In the 1910s,

text: Vesto Slipher

text: (and later

text: Carl Wilhelm Wirtz

text: ) interpreted the

text: red shift

text: of

text: spiral nebulae

text: as a

text: Doppler shift

text: that indicated they were receding from Earth. However, it is difficult to determine the distance to astronomical objects. One way is to compare the physical size of an object to its

text: angular size

text: , but a physical size must be assumed to do this. Another method is to measure the

text: brightness

text: of an object and assume an intrinsic

text: luminosity

text: , from which the distance may be determined using the

text: inverse square law

text: . Due to the difficulty of using these methods, they did not realize that the nebulae were actually galaxies outside our own

text: Milky Way

text: , nor did they speculate about the cosmological implications. In 1927, the

text: Belgian

text: Roman Catholic

text: priest

text: Georges Lemaître

text: independently derived the Friedmann–Lemaître–Robertson–Walker equations and proposed, on the basis of the recession of spiral nebulae, that the universe began with the "explosion" of a "primeval

text: atom

text: "—which was later called the

text: Big Bang

text: . In 1929,

text: Edwin Hubble

text: provided an observational basis for Lemaître's theory. Hubble showed that the spiral nebulae were galaxies by determining their distances using measurements of the brightness of

text: Cepheid variable

text: stars. He discovered a relationship between the redshift of a galaxy and its distance. He interpreted this as evidence that the galaxies are receding from Earth in every direction at speeds proportional to their distance. This fact is now known as

text: Hubble's law

text: , though the numerical factor Hubble found relating recessional velocity and distance was off by a factor of ten, due to not knowing about the types of Cepheid variables.

text: About the real essence of the Milky Way, Ṭūsī in his Tadhkira writes:"The Milky Way, i.e. the galaxy, is made up of a very large number of small, tightly-clustered stars, which, on account of their concentration and smallness, seem to be cloudy patches. because of this, it was likend to milk in color."Three centuries later the proof of the Milky Way consisting of many stars came in 1610 when Galileo Galilei used a telescope to study the Milky Way and discovered that it is really composed of a huge number of faint stars.

text: About the real essence of the Milky Way, Ṭūsī in his Tadhkira writes:"The Milky Way, i.e. the galaxy, is made up of a very large number of small, tightly-clustered stars, which, on account of their concentration and smallness, seem to be cloudy patches. because of this, it was likend to milk in color."Three centuries later the proof of the Milky Way consisting of many stars came in 1610 when

text: Galileo Galilei

text: used a

text: telescope

text: to study the Milky Way and discovered that it is really composed of a huge number of faint stars.

text: Size functions have been initially introduced as a mathematical tool for shape comparison in computer vision and pattern recognition, and have constituted the seed of size theory.The main point is that size functions are invariant for every transformation preserving the measuring function. Hence, they can be adapted to many different applications, by simply changing the measuring function in order to get the wanted invariance. Moreover, size functions show properties of relative resistance to noise, depending on the fact that they distribute the information all over the half-plane

text: Size functions have been initially introduced as a mathematical tool for shape comparison in

text: computer vision

text: and

text: pattern recognition

text: , and have constituted the seed of

text: size theory

text: .The main point is that size functions are invariant for every transformation preserving the

text: measuring function

text: . Hence, they can be adapted to many different applications, by simply changing the

text: measuring function

text: in order to get the wanted invariance. Moreover, size functions show properties of relative resistance to noise, depending on the fact that they distribute the information all over the half-plane

text: How these clusters are formed is not yet known, but their formation might well be related to that of globular clusters. Why M31 has such clusters, while the Milky Way does not, is not yet known. It is also unknown if any other galaxy contains these types of clusters, but it would be very unlikely that M31 is the sole galaxy with extended clusters.

text: "M33 in Andromeda" is returning once again to the Space Beagle as it finally arrives at the Andromeda galaxy. As it approaches, the crew are bombarded by message after message to not come any closer and to go home. The sociologist on board proposes that maybe something is just trying to get them to go home and not to keep them from there. They press onward and discover that every planet in the galaxy is covered in rain forests, with the same species on each one. Underneath the rain forests they find ruins of civilizations. They discover that the entire galaxy (or maybe just the areas around the suns) is covered in a light mist of space dust. The mist is a sentient creature that lives off the "life energy" of other creatures. It was originally a self-replicating puff of vapor over a swamp but now embraces the galaxy. To get more life energy it converts whole planets into rain forest worlds. That's why it tried to get the Beagle to leave so it could follow it back to our galaxy and take it over. When the crew figure this out, they set up the means to destroy the mist. The reference to M33 in the title of the story is apparently an error: the galaxy described is the Andromeda Galaxy (M31), rather than the Triangulum Galaxy (M33). The latter is in the constellation Triangulum rather than Andromeda (constellation).

text: Andromeda Galaxy

text: (M31), rather than the

text: Triangulum Galaxy

text: (M33). The latter is in the constellation

text: Triangulum

text: rather than

text: Andromeda (constellation)

text: The Milky Way has several satellite galaxies and is part of the Local Group of galaxies, which is a component of the Virgo Supercluster, which is itself a component of the Laniakea Supercluster.

text: The Milky Way has several

text: satellite galaxies

text: and is part of the

text: Local Group

text: of galaxies, which is a component of the

text: Virgo Supercluster

text: , which is itself a component of the

text: Laniakea Supercluster

text: The liver is the only visceral organ that possesses remarkable capacity to regenerate. The liver can regenerate after either surgical removal or after chemical injury. It is known that as little as 25% of the original liver mass can regenerate back to its full size. The process of regeneration in mammals is mainly compensatory growth because only the mass of the liver is replaced, not the shape. However, in lower species such as fish, both liver size and shape can be replaced.

text: The

text: liver

text: is the only

text: visceral organ

text: that possesses remarkable capacity to regenerate. The liver can regenerate after either surgical removal or after chemical injury. It is known that as little as 25% of the original liver mass can regenerate back to its full size. The process of regeneration in mammals is mainly compensatory growth because only the mass of the liver is replaced, not the shape. However, in lower species such as fish, both liver size and shape can be replaced.

text: Many of these galaxies are either interacting galaxies or galaxies that are the remnants of the merger of two smaller galaxies. The interaction process will produce various tidal features, such as tidal tails and tidal bridges, that may last well after the progenitor galaxies' disks and nuclei have merged. Although the tidal tails are described as several different visual phenomena ("counter-tails", "filaments", "loops"), they are all manifestations of the same phenomena.

text: Looking beyond the Milky Way, there are at least 2 trillion other galaxies in the observable universe. The distances between galaxies are on the order of a million times further than those between the stars. Because of the speed of light limit on how fast any material objects can travel in space, intergalactic travel would either have to involve voyages lasting millions of years, or a possible faster than light propulsion method based on speculative physics, such as the Alcubierre drive. There are, however, no scientific reasons for stating that intergalactic travel is impossible in principle.

text: Looking beyond the Milky Way, there are at least 2 trillion other galaxies in the observable universe. The distances between galaxies are on the order of a million times further than those between the stars. Because of the speed of light limit on how fast any material objects can travel in space, intergalactic travel would either have to involve voyages lasting millions of years, or a possible faster than light propulsion method based on speculative physics, such as the

text: Alcubierre drive

text: . There are, however, no scientific reasons for stating that

text: intergalactic travel

text: is impossible in principle.

text: Describes double stars, variable star, star clusters, nebulas, globular clusters, and galaxies. Explains how astronomers determine the distances to stars and galaxies, how sky objects are designated, and how to use deep-sky charts. Includes an atlas of 20 star charts.The charts are ideal for stargazers using a small telescope or binoculars.

text: Describes

text: double stars

text: variable star

text: star clusters

text: nebulas

text: globular clusters

text: , and

text: galaxies

text: . Explains how astronomers determine the distances to stars and galaxies, how sky objects are designated, and how to use deep-sky charts. Includes an atlas of 20 star charts.The charts are ideal for stargazers using a small telescope or binoculars.

text: The Centaurus A/M83 Group is a complex group of galaxies in the constellations Hydra, Centaurus, and Virgo.  The group may be roughly divided into two subgroups. The Cen A Subgroup, at a distance of 11.9 Mly (3.66 Mpc), is centered on Centaurus A, a nearby radio galaxy.  The M83 Subgroup, at a distance of 14.9 Mly (4.56 Mpc),  is centered on the Messier 83 (M83), a face-on spiral galaxy.

text: The Centaurus A/M83 Group is a complex

text: group of galaxies

text: in the

text: constellation

text: s

text: Hydra

text: Centaurus

text: , and

text: Virgo

text: .  The group may be roughly divided into two subgroups. The Cen A Subgroup, at a distance of 11.9

text: Mly

text: Mpc

text: ), is centered on

text: Centaurus A

text: , a nearby

text: radio galaxy

text: .  The M83 Subgroup, at a distance of 14.9

text: Mly

text: Mpc

text: ),  is centered on the

text: Messier 83

text: (M83), a face-on

text: spiral galaxy

text: Spiral galaxies consist of a rotating disk of stars and interstellar medium, along with a central bulge of generally older stars. Extending outward from the bulge are relatively bright arms. In the Hubble classification scheme, spiral galaxies are listed as type S, followed by a letter (a, b, or c) that indicates the degree of tightness of the spiral arms and the size of the central bulge. An Sa galaxy has tightly wound, poorly defined arms and possesses a relatively large core region. At the other extreme, an Sc galaxy has open, well-defined arms and a small core region. A galaxy with poorly defined arms is sometimes referred to as a flocculent spiral galaxy; in contrast to the grand design spiral galaxy that has prominent and well-defined spiral arms. The speed in which a galaxy rotates is thought to correlate with the flatness of the disc as some spiral galaxies have thick bulges, while others are thin and dense.

text: Spiral galaxies consist of a rotating disk of stars and interstellar medium, along with a central bulge of generally older stars. Extending outward from the

text: bulge

text: are relatively bright arms. In the Hubble classification scheme, spiral galaxies are listed as type S, followed by a letter (a, b, or c) that indicates the degree of tightness of the spiral arms and the size of the central bulge. An Sa galaxy has tightly wound, poorly defined arms and possesses a relatively large core region. At the other extreme, an Sc galaxy has open, well-defined arms and a small core region. A galaxy with poorly defined arms is sometimes referred to as a

text: flocculent spiral galaxy

text: ; in contrast to the

text: grand design spiral galaxy

text: that has prominent and well-defined spiral arms. The speed in which a galaxy rotates is thought to correlate with the flatness of the disc as some spiral galaxies have thick bulges, while others are thin and dense.

text: M82 was previously believed to be an irregular galaxy.  In 2005, however, two symmetric spiral arms were discovered in near-infrared (NIR) images of M82.  The arms were detected by subtracting an axisymmetric exponential disk from the NIR images.  Even though the arms were detected in NIR images, they are bluer than the disk. The arms were previously missed due to M82's high disk surface brightness, the nearly edge-on view of this galaxy (~80°), and obscuration by a complex network of dusty filaments in its optical images. These arms emanate from the ends of the NIR bar and can be followed for the length of 3 disc scales. Assuming that the northern part of M82 is nearer to us, as most of the literature does, the observed sense of rotation implies trailing arms.

text: M82 was previously believed to be an

text: irregular galaxy

text: .  In 2005, however, two symmetric

text: spiral arm

text: s were discovered in

text: near-infrared

text: (NIR) images of M82.  The arms were detected by subtracting an

entity_section: Rotational symmetry with respect to any angle

text: axisymmetric

text: exponential disk from the NIR images.  Even though the arms were detected in NIR images, they are bluer than the disk. The arms were previously missed due to M82's high disk

text: surface brightness

text: , the nearly edge-on view of this galaxy (~80°), and obscuration by a complex network of dusty filaments in its optical images. These arms emanate from the ends of the NIR

text: bar

text: and can be followed for the length of 3

text: disc

text: scales. Assuming that the northern part of M82 is nearer to us, as most of the literature does, the observed sense of rotation implies trailing arms.

text: Inserting the above minimum numbers into the equation gives a minimum N of 20. Inserting the maximum numbers gives a maximum of 50,000,000. Drake states that given the uncertainties, the original meeting concluded that N ≈ L, and there were probably between 1000 and 100,000,000 civilizations in the Milky Way galaxy.

text: Inserting the above minimum numbers into the equation gives a minimum N of 20. Inserting the maximum numbers gives a maximum of 50,000,000. Drake states that given the uncertainties, the original meeting concluded that N ≈ L, and there were probably between 1000 and 100,000,000 civilizations in the

text: Milky Way

text: galaxy.

text: When comparing dental morphology the focus is on overall size and tooth shape.  To measure the size and shape, Penrose's size and shape statistic is used. To calculate tooth size, the sum of the tooth area is taken. Factor analysis is applied to tooth size to achieve tooth shape. Results have shown that tooth size of Andaman islanders is closest to the tooth size of Chinese and Japanese people . Therefore, the indodont dental morphology of the Andamanese indicates a retention of dental morphology from Southeast Asians in early-mid Holocene.

text: The Dodge Polara was an automobile introduced in the United States for the 1960 model year as Dodge's top-of-the-line full-size car; after the introduction of the Dodge Custom 880 in 1962, the Polara nameplate designated a step below the full sized best trimmed Dodge model; the Polara that year had been downsized to what was in effect intermediate, or mid-size status. In its various forms, the Polara name was used by Dodge until 1973, when its position in Dodge's line-up was replaced by the Dodge Monaco. The name Polara is a reference to the Polaris star, in a marketing attempt to appeal to the excitement surrounding the Space Race during the early 1960s. The Polara was a competitor to the Ford Galaxie 500 and the Chevrolet Impala.

text: The Dodge Polara was an automobile introduced in the United States for the 1960

text: model year

text: as

text: Dodge

text: 's top-of-the-line

text: full-size car

text: ; after the introduction of the

text: Dodge Custom 880

text: in 1962, the Polara nameplate designated a step below the full sized best trimmed Dodge model; the Polara that year had been downsized to what was in effect intermediate, or mid-size status. In its various forms, the Polara name was used by Dodge until 1973, when its position in Dodge's line-up was replaced by the

text: Dodge Monaco

text: . The name Polara is a reference to the

text: Polaris

text: star, in a marketing attempt to appeal to the excitement surrounding the

text: Space Race

text: during the early 1960s. The Polara was a competitor to the

text: Ford Galaxie 500

text: and the

text: Chevrolet Impala

text: Barless spiral galaxies are one of three general types of spiral galaxies under the de Vaucouleurs system classification system, the other two being intermediate spiral galaxy and barred spiral galaxy. Under the Hubble tuning fork, it is one of two general types of spiral galaxy, the other being barred spirals.

text: Barless spiral galaxies are one of three general types of spiral galaxies under the de Vaucouleurs system classification system, the other two being

text: intermediate spiral galaxy

text: and barred spiral galaxy. Under the Hubble tuning fork, it is one of two general types of spiral galaxy, the other being barred spirals.

text: "Spiral nebula" was a term used to describe galaxies with a visible spiral structure, such as the Whirlpool Galaxy, before it was understood that these objects existed outside our Milky Way galaxy. The question of whether such objects were separate galaxies independent of the Milky Way, or a type of nebula existing within our own galaxy, was the subject of the Great Debate of 1920, between Heber Curtis of Lick Observatory and Harlow Shapley of Mt. Wilson Observatory. Beginning in 1923, Edwin Hubble observed Cepheid variables in several spiral nebulae, including the so-called "Andromeda Nebula", proving that they are, in fact, entire galaxies outside our own. The term "spiral nebula" has since fallen into disuse.

text: "Spiral nebula" was a term used to describe galaxies with a visible spiral structure, such as the

text: Whirlpool Galaxy

text: , before it was understood that these objects existed outside our Milky Way galaxy. The question of whether such objects were separate galaxies independent of the Milky Way, or a type of

text: nebula

text: existing within our own galaxy, was the subject of the

text: Great Debate

text: of 1920, between

text: Heber Curtis

text: of

text: Lick Observatory

text: and

text: Harlow Shapley

text: of

text: Mt. Wilson Observatory

text: . Beginning in 1923,

text: Edwin Hubble

text: observed

text: Cepheid variables

text: in several spiral nebulae, including the so-called

text: "Andromeda Nebula"

text: , proving that they are, in fact, entire galaxies outside our own. The term "spiral nebula" has since fallen into disuse.

text: Ori military tactics varied during the initial incursions into the Milky Way galaxy and the full-scale invasion that was later achieved through the Supergate. The initial incursions were achieved through lone Priors who were sent to worlds in the Milky Way galaxy, preaching to the populace and distributing copies of the Book of Origin. When the people failed to comply, more drastic measures were taken, eventually to the point of destroying the population. The show features powerful Ori weapons in , ships in , control chairs like that in  and Supergates in . The Ori can be killed by Merlin's Sangraal weapon, which nullifies ascended beings. As seen in The Ark of Truth, there is also an Ark that Cooper considered "a truly fascinating centerpiece" and "mass brain-washing device" which causes people to see the truth in any given situation. Comparing the Ark to television as it is "a box that light comes out of, and you believe what it says", Cooper left it open whether the choice to do it without guns was ultimately the better method.

text: Ori military tactics varied during the initial incursions into the Milky Way galaxy and the full-scale invasion that was later achieved through the Supergate. The initial incursions were achieved through lone Priors who were sent to worlds in the Milky Way galaxy, preaching to the populace and distributing copies of the Book of Origin. When the people failed to comply, more drastic measures were taken, eventually to the point of destroying the population. The show features powerful Ori weapons in , ships in , control chairs like that in  and

text: Supergates

text: in . The Ori can be killed by

text: Merlin's

text: Sangraal weapon, which nullifies ascended beings. As seen in The Ark of Truth, there is also an Ark that Cooper considered "a truly fascinating centerpiece" and "mass brain-washing device" which causes people to see the truth in any given situation. Comparing the Ark to television as it is "a box that light comes out of, and you believe what it says", Cooper left it open whether the choice to do it without guns was ultimately the better method.

text: Membership in a star cluster or star system permits an assignment of rough ages to a large number of stars present within. When one can determine the age of stars through other methods, such as the ones listed above, one can identify the age of all of the bodies in a system. This is especially useful in clusters of stars which exhibit a large amount of variety in their stellar masses, evolutionary stages, and classifications. While not entirely independent of the properties of the stars in the cluster, system, or other reasonably-sized association of stars, an astronomer would only need a representative sample of stars to determine the age of the cluster, rather than painstakingly finding the age of every star in the cluster through other properties.

text: Membership in a

text: star cluster

text: or

text: star system

text: permits an assignment of rough ages to a large number of stars present within. When one can determine the age of stars through other methods, such as the ones listed above, one can identify the age of all of the bodies in a system. This is especially useful in clusters of stars which exhibit a large amount of variety in their stellar masses, evolutionary stages, and classifications. While not entirely independent of the properties of the stars in the cluster, system, or other reasonably-sized association of stars, an astronomer would only need a representative sample of stars to determine the age of the cluster, rather than painstakingly finding the age of every star in the cluster through other properties.

text: Recently, as growing evidence has indicated that the vast majority of dwarf ellipticals have properties that are not at all similar to elliptical galaxies, but are closer to irregular and late-type spiral galaxies, this term has been used to refer to all of the galaxies that share the properties of those above. These sorts of galaxies may in fact be the most common type of galaxies in the universe, but are much harder to see than other types of galaxies because they are so faint.

text: Super star clusters, such as Westerlund 1 in the Milky Way, may be the precursors of globular clusters.

text: Super star clusters

text: , such as

text: Westerlund 1

text: in the Milky Way, may be the precursors of globular clusters.

text: Galaxy X is a postulated dark satellite dwarf galaxy of the Milky Way Galaxy. If it exists, it would be composed mostly of dark matter and interstellar gas with few stars. Its claimed location is some  from the Sun, behind the disk of the Milky Way, and some  in extent. Galactic coordinates would be (l=-27.4°,b=-1.08°).

text: Galaxy X is a postulated

text: dark

text: satellite

text: dwarf

text: galaxy

text: of the

text: Milky Way Galaxy

text: . If it exists, it would be composed mostly of

text: dark matter

text: and

text: interstellar gas

text: with few

text: star

text: s. Its claimed location is some  from the Sun, behind the disk of the Milky Way, and some  in extent.

text: Galactic coordinates

text: would be (l=-27.4°,b=-1.08°).

text: The foreground galaxy lies  directly in front in our line of sight to a more distant galaxy. Due to the passage of the light from the background galaxy through the gravity field of the foreground galaxy, the background galaxy's light is lensed by the warped spacetime environment of the foreground galaxy. Thus giving the background galaxy a warped appearance. Unlike most lensed galaxies, the shape of the lensed light of this background galaxy appears shaped like a horseshoe.

text: The foreground galaxy lies  directly in front in our line of sight to a more distant galaxy. Due to the passage of the light from the background galaxy through the gravity field of the foreground galaxy, the background galaxy's light is lensed by the warped spacetime environment of the foreground galaxy. Thus giving the background galaxy a warped appearance. Unlike most lensed galaxies, the shape of the lensed light of this background galaxy appears shaped like a

text: horseshoe

text: The  of elliptical galaxies paints them as galaxies where star formation finished after an initial burst at high-redshift, leaving them to shine with only their aging stars. Elliptical galaxies typically appear yellow-red, which is in contrast to the distinct blue tinge of most spiral galaxies. In spirals, this blue color emanates largely from the young, hot stars in their spiral arms. Very little star formation is thought to occur in elliptical galaxies, because of their lack of gas compared to spiral or irregular galaxies. However, in recent years, evidence has shown that a reasonable proportion (~25%) of these galaxies have residual gas reservoirs and low level star-formation. Researchers with the Herschel Space Observatory have speculated that the central black holes in elliptical galaxies keep the gas from cooling enough for star formation.

text: The  of elliptical galaxies paints them as galaxies where

text: star formation

text: finished after an initial burst at high-redshift, leaving them to shine with only their aging stars. Elliptical galaxies typically appear yellow-red, which is in contrast to the distinct blue tinge of most

text: spiral galaxies

text: . In spirals, this blue color emanates largely from the young, hot stars in their spiral arms. Very little

text: star formation

text: is thought to occur in elliptical galaxies, because of their lack of gas compared to spiral or irregular galaxies. However, in recent years, evidence has shown that a reasonable proportion (~25%) of these galaxies have residual gas reservoirs and low level star-formation. Researchers with the

text: Herschel Space Observatory

text: have speculated that the central black holes in elliptical galaxies keep the gas from cooling enough for star formation.

text: Two smaller galaxies and a number of dwarf galaxies in the Local Group orbit the Milky Way. The largest of these is the Large Magellanic Cloud with a diameter of 14,000 light-years. It has a close companion, the Small Magellanic Cloud. The Magellanic Stream is a stream of neutral hydrogen gas extending from these two small galaxies across 100° of the sky. The stream is thought to have been dragged from the Magellanic Clouds in tidal interactions with the Milky Way. Some of the dwarf galaxies orbiting the Milky Way are Canis Major Dwarf (the closest), Sagittarius Dwarf Elliptical Galaxy, Ursa Minor Dwarf, Sculptor Dwarf, Sextans Dwarf, Fornax Dwarf, and Leo I Dwarf. The smallest dwarf galaxies of the Milky Way are only 500 light-years in diameter. These include Carina Dwarf, Draco Dwarf, and Leo II Dwarf. There may still be undetected dwarf galaxies that are dynamically bound to the Milky Way, which is supported by the detection of nine new satellites of the Milky Way in a relatively small patch of the night sky in 2015. There are also some dwarf galaxies that have already been absorbed by the Milky Way, such as Omega Centauri.

text: Two smaller galaxies and a number of

text: dwarf galaxies

text: in the Local Group

text: orbit

text: the Milky Way. The largest of these is the

text: Large Magellanic Cloud

text: with a diameter of 14,000 light-years. It has a close companion, the

text: Small Magellanic Cloud

text: . The

text: Magellanic Stream

text: is a stream of neutral

text: hydrogen

text: gas extending from these two small galaxies across 100° of the sky. The stream is thought to have been dragged from the Magellanic Clouds in tidal interactions with the Milky Way. Some of the

text: dwarf galaxies orbiting the Milky Way

text: are

text: Canis Major Dwarf

text: (the closest),

text: Sagittarius Dwarf Elliptical Galaxy

text: Ursa Minor Dwarf

text: Sculptor Dwarf

text: Sextans Dwarf

text: Fornax Dwarf

text: , and

text: Leo I Dwarf

text: . The smallest dwarf galaxies of the Milky Way are only 500 light-years in diameter. These include

text: Carina Dwarf

text: Draco Dwarf

text: , and

text: Leo II Dwarf

text: . There may still be undetected dwarf galaxies that are dynamically bound to the Milky Way, which is supported by the detection of nine new satellites of the Milky Way in a relatively small patch of the night sky in 2015. There are also some dwarf galaxies that have already been absorbed by the Milky Way, such as

text: Omega Centauri

text: "Substance" here means what something is in itself. (For more on the philosophical concept, see Substance theory.) A hat's shape is not the hat itself, nor is its colour the hat, nor is its size, nor its softness to the touch, nor anything else about it perceptible to the senses. The hat itself (the "substance") has the shape, the colour, the size, the softness and the other appearances, but is distinct from them. Whereas the appearances, which are referred to by the philosophical term accidents are perceptible to the senses, the substance is not.

text: "Substance" here means what something is in itself. (For more on the philosophical concept, see

text: Substance theory

text: .) A hat's shape is not the hat itself, nor is its colour the hat, nor is its size, nor its softness to the touch, nor anything else about it perceptible to the senses. The hat itself (the "substance") has the shape, the colour, the size, the softness and the other appearances, but is distinct from them. Whereas the appearances, which are referred to by the philosophical term

text: accidents

text: are perceptible to the senses, the substance is not.

text: The Antennae galaxies also contain a relatively young collection of massive globular clusters that were possibly formed as a result of the collision between the two galaxies.  The young age of these clusters is in contrast to the average age of most known globular clusters, around 12 billion years old, with the formation of the globulars likely originating from shockwaves, generated by the collision of the galaxies, compressing large, massive molecular clouds. The densest regions of the collapsing and compressing clouds are believed to be the birthplace of the clusters.

text: The structure and stellar content of M32 is difficult to explain by traditional galaxy formation models. Some simulations suggest a scenario in which the strong tidal field of M31 can transform a spiral galaxy into a compact elliptical. As a small spiral galaxy falls into the central parts of M31, most of the outer layers of the smaller spiral are stripped away. The central bulge of the galaxy is much less affected and retains its morphology. Tidal effects trigger a massive star burst in the core, resulting in the high density of M32 observed today. There is also evidence that M32 has an outer disk.

text: The structure and stellar content of M32 is difficult to explain by traditional

text: galaxy formation

text: models. Some simulations suggest a scenario in which the strong

text: tidal field

text: of M31 can transform a

text: spiral galaxy

text: into a compact elliptical. As a small spiral galaxy falls into the central parts of M31, most of the outer layers of the smaller spiral are stripped away. The central bulge of the galaxy is much less affected and retains its morphology. Tidal effects trigger a massive star burst in the core, resulting in the high density of M32 observed today. There is also evidence that M32 has an outer disk.

text: in the Rare Earth equation) are too restrictive. James Kasting cites the Titius-Bode law to contend that it is a misnomer to describe habitable zones as narrow when there is a 50% chance of at least one planet orbiting within one. In 2013 a study that was published in the journal Proceedings of the National Academy of Sciences calculated that about "one in five" of all sun-like stars are expected to have earthlike planets "within the habitable zones of their stars"; 8.8 billion of them therefore exist in the Milky Way galaxy alone. On 4 November 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of sun-like stars and red dwarf stars within the Milky Way Galaxy. 11 billion of these estimated planets may be orbiting sun-like stars.

text: in the Rare Earth equation) are too restrictive.

text: James Kasting

text: cites the

text: Titius-Bode law

text: to contend that it is a misnomer to describe habitable zones as narrow when there is a 50% chance of at least one planet orbiting within one. In 2013 a study that was published in the journal Proceedings of the National Academy of Sciences calculated that about "one in five" of all

text: sun

text: -like

text: star

text: s are expected to have earthlike planets "within the

text: habitable zone

text: s of their stars"; 8.8 billion of them therefore exist in the Milky Way galaxy alone. On 4 November 2013, astronomers reported, based on

text: Kepler space mission

text: data, that there could be as many as 40 billion

text: Earth-sized

text: planets

text: orbiting in the

text: habitable zone

text: s of

text: sun-like stars

text: and

text: red dwarf stars

text: within the

text: Milky Way Galaxy

text: . 11 billion of these estimated planets may be orbiting sun-like stars.

text: Season nine of Stargate SG-1, an American-Canadian television series, began airing on July 15, 2005 on SCI FI. The ninth season concluded on March 10, 2006, after 20 episodes on the same channel. The series was originally developed by Brad Wright and Jonathan Glassner, and Brad Wright, Robert C. Cooper, Joseph Mallozzi and Paul Mullie served as executive producers. The season arc centers on the new threat of the Ori, a race who Daniel Jackson (Michael Shanks) and Vala Mal Doran (Claudia Black) unleash  in an unknown galaxy, and who are threatening to prepare for a crusade into the Milky Way galaxy to convert the beings to their religion called Origin.

text: Season nine of

text: Stargate SG-1

text: , an American-Canadian

text: television series

text: , began airing on July 15, 2005 on

text: SCI FI

text: . The ninth season concluded on March 10, 2006, after 20 episodes on the same channel. The series was originally developed by

text: Brad Wright

text: and

text: Jonathan Glassner

text: , and Brad Wright,

text: Robert C. Cooper

text: Joseph Mallozzi

text: and

text: Paul Mullie

text: served as executive producers. The season arc centers on the new threat of the

text: Ori

text: , a race who

text: Daniel Jackson

text: (Michael Shanks) and

text: Vala Mal Doran

text: Claudia Black

text: ) unleash  in an unknown galaxy, and who are threatening to prepare for a crusade into the

text: Milky Way galaxy

text: to convert the beings to their religion called

text: Origin

text: Bars are thought to be temporary phenomena in the lives of spiral galaxies; the bar structures decay over time, transforming galaxies from barred spirals to more "regular" spiral patterns. Past a certain size the accumulated mass of the bar compromises the stability of the overall bar structure. Barred spiral galaxies with high mass accumulated in their center tend to have short, stubby bars. Since so many spiral galaxies have bar structures, it is likely that they are recurring phenomena in spiral galaxy development. The oscillating evolutionary cycle from spiral galaxy to barred spiral galaxy is thought to take on the average about two billion years.

text: This is another category in which the majority of objects are interacting galaxies. As noted in the category name, the spiral galaxies look perturbed. Arp originally described some of the elliptical galaxies as repelling.

text: A much larger galaxy cluster is the redshift-0.0354 Abell 2063. The cluster is thought to be interacting with the nearby galaxy group MKW 3s, based on radial velocity measurements of galaxies and the positioning of the cD galaxy at the center of Abell 2063. The active galaxy at the center of MKW 3s—NGC 5920—appears to be creating a bubble of hot gas from its radio activity. Near the 5th-magnitude star Pi Serpentis lies AWM 4, a cluster containing an excess of metals in the intracluster medium. The central galaxy, NGC 6051, is a radio galaxy that is probably responsible for this enrichment. Similar to AWM 4, the cluster Abell 2052 has central cD radio galaxy, 3C 317. This radio galaxy is believed to have restarted after a period of inactivity less than 200 years ago. The galaxy has over 40,000 known globular clusters, the highest known total of any galaxy as of 2002.

text: A much larger galaxy cluster is the redshift-0.0354

text: Abell 2063

text: . The cluster is thought to be interacting with the nearby galaxy group

text: MKW 3s

text: , based on radial velocity measurements of galaxies and the positioning of the

text: cD galaxy

text: at the center of Abell 2063. The active galaxy at the center of MKW 3s—

text: NGC 5920

text: —appears to be creating a bubble of hot gas from its radio activity. Near the 5th-magnitude star

text: Pi Serpentis

text: lies

text: AWM 4

text: , a cluster containing an excess of metals in the intracluster medium. The central galaxy,

text: NGC 6051

text: , is a

text: radio galaxy

text: that is probably responsible for this enrichment. Similar to AWM 4, the cluster

text: Abell 2052

text: has central cD radio galaxy,

text: 3C 317

text: . This radio galaxy is believed to have restarted after a period of inactivity less than 200 years ago. The galaxy has over 40,000 known globular clusters, the highest known total of any galaxy as of 2002.

text: Spiral galaxies resemble spiraling pinwheels. Though the stars and other visible material contained in such a galaxy lie mostly on a plane, the majority of mass in spiral galaxies exists in a roughly spherical halo of dark matter that extends beyond the visible component, as demonstrated by the universal rotation curve concept.

text: Spiral galaxies resemble spiraling pinwheels. Though the stars and other visible material contained in such a galaxy lie mostly on a plane, the majority of mass in spiral galaxies exists in a roughly spherical halo of

text: dark matter

text: that extends beyond the visible component, as demonstrated by the universal rotation curve concept.

text: In 1935, Harlow Shapley declared that this galaxy was the third largest spiral galaxy by angular size then known, smaller only than the Andromeda Galaxy (M31) and the Triangulum Galaxy (M33), being wider that the full moon. (Modern estimates are more conservative, giving the apparent size as one-half to two-thirds the diameter of the full moon).

text: In 1935,

text: Harlow Shapley

text: declared that this galaxy was the third largest spiral galaxy by angular size then known, smaller only than the

text: Andromeda Galaxy

text: (M31) and the

text: Triangulum Galaxy

text: (M33), being wider that the

text: full moon

text: . (Modern estimates are more conservative, giving the apparent size as one-half to two-thirds the diameter of the full moon).

text: Total Series Production includes Custom, Custom 500, Seven Litre, Station Wagon, LTD, and all Galaxie models. Galaxie Production includes Galaxie, Galaxie 500, Galaxie 500XL, XL, and Galaxie 500 LTD when LTD was not a separate model (until 1967).

text: In 1913, Ejnar Hertzsprung conducted research on Cepheids. His research would later require revision, however. In 1915, Harlow Shapley used Cepheids to place initial constraints on the size and shape of the Milky Way, and of the placement of our Sun within it. In 1924, Edwin Hubble established the distance to classical Cepheid variables in the Andromeda Galaxy, until then known as the Andromeda Nebula, and showed that the variables were not members of the Milky Way.  Hubble's finding settled the question of whether the Milky Way represented the entire Universe, or was merely one of numerous galaxies in the Universe [see Great Debate (astronomy)].

text: In 1913,

text: Ejnar Hertzsprung

text: conducted research on Cepheids. His research would later require revision, however. In 1915,

text: Harlow Shapley

text: used Cepheids to place initial constraints on the size and shape of the

text: Milky Way

text: , and of the placement of our Sun within it. In 1924,

text: Edwin Hubble

text: established the distance to classical Cepheid variables in the

text: Andromeda Galaxy

text: , until then known as the Andromeda

text: Nebula

text: , and showed that the variables were not members of the Milky Way.  Hubble's finding settled the question of whether the Milky Way represented the entire Universe, or was merely one of numerous

text: galaxies

text: in the Universe [see

text: Great Debate (astronomy)

text: A galaxy group or group of galaxies (GrG) is an aggregation of galaxies comprising about 50 or fewer gravitationally bound members, each at least as luminous as the Milky Way (about 10 times the luminosity of the Sun); collections of galaxies larger than groups that are first-order clustering are called galaxy clusters. The groups and clusters of galaxies can themselves be clustered, into superclusters of galaxies.

text: A galaxy group or group of galaxies (GrG) is an aggregation of

text: galaxies

text: comprising about 50 or fewer

text: gravitationally bound

text: members, each at least as

text: luminous

text: as the

text: Milky Way

text: (about 10 times the luminosity of the

text: Sun

text: ); collections of galaxies larger than groups that are first-order clustering are called

text: galaxy cluster

text: s. The

text: groups and clusters

text: of galaxies can themselves be clustered, into

text: supercluster

text: s of galaxies.

text: Outside of the Milky Way, there are no bright deep-sky objects for amateur astronomers in Serpens Caput, with nothing else above 10th magnitude. The brightest is NGC 5962, a spiral galaxy positioned around 28 megaparsecs distant with an apparent magnitude of 11.34. Slightly fainter is NGC 5921, a barred spiral galaxy with a LINER-type active galactic nucleus situated somewhat closer at a distance of 21 megaparsecs. A type II supernova was observed in this galaxy in 2001 and was designated SN 2001X. Fainter still are the spirals NGC 5964 and NGC 6118, with the latter being host to the supernova SN 2004dk.

text: Outside of the Milky Way, there are no bright deep-sky objects for amateur astronomers in Serpens Caput, with nothing else above 10th magnitude. The brightest is

text: NGC 5962

text: , a

text: spiral galaxy

text: positioned around 28 megaparsecs distant with an apparent magnitude of 11.34. Slightly fainter is

text: NGC 5921

text: , a

text: barred spiral galaxy

text: with a

text: LINER

text: -type

text: active galactic nucleus

text: situated somewhat closer at a distance of 21 megaparsecs. A

text: type II supernova

text: was observed in this galaxy in 2001 and was designated SN 2001X. Fainter still are the spirals

text: NGC 5964

text: and

text: NGC 6118

text: , with the latter being host to the

text: supernova

text: SN 2004dk

text: In 2012, she embarks on the SDF-2 Megaroad-01 colony ship, which disappears 4 years later during its voyage towards the center of the Milky Way galaxy, becoming a legend in the Macross universe since then.

text: In 2012, she embarks on the

entity_name: The Super Dimension Fortress Macross: Flash Back 2012

text: SDF-2 Megaroad-01

text: colony ship, which disappears 4 years later during its voyage towards the center of the

text: Milky Way

text: galaxy, becoming a legend in the

text: Macross

text: universe since then.

text: At a distance of  it is the most distant Milky Way globular cluster yet known, located in the galactic halo surrounding the Milky way galaxy.  With an age of only 7.5 Gyr, it is likely to have been incorporated into our galaxy long after the formation of the Milky Way, probably during an interaction with the Small Magellanic Cloud

text: At a distance of  it is the most distant Milky Way globular cluster yet known, located in the

text: galactic halo

text: surrounding the

text: Milky way

text: galaxy.  With an age of only 7.5 Gyr, it is likely to have been incorporated into our galaxy long after the formation of the Milky Way, probably during an interaction with the

text: Small Magellanic Cloud

text: Based on Kepler findings, astronomer Seth Shostak estimated in 2011 that "within a thousand light-years of Earth", there are "at least 30,000" habitable planets. Also based on the findings, the Kepler team has estimated that there are "at least 50 billion planets in the Milky Way", of which "at least 500 million" are in the habitable zone. In March 2011, astronomers at NASA's Jet Propulsion Laboratory (JPL) reported that about "1.4 to 2.7 percent" of all Sun-like stars are expected to have Earth-size planets "within the habitable zones of their stars". This means there are "two billion" of these "Earth analogs" in the Milky Way alone. The JPL astronomers also noted that there are "50 billion other galaxies", potentially yielding more than one sextillion "Earth analog" planets if all galaxies have similar numbers of planets to the Milky Way.

text: Based on Kepler findings, astronomer

text: Seth Shostak

text: estimated in 2011 that "within a thousand light-years of Earth", there are "at least 30,000" habitable planets. Also based on the findings, the Kepler team has estimated that there are "at least 50 billion planets in the Milky Way", of which "at least 500 million" are in the

text: habitable zone

text: . In March 2011, astronomers at NASA's

text: Jet Propulsion Laboratory

text: (JPL) reported that about "1.4 to 2.7 percent" of all Sun-like stars are expected to have Earth-size planets "within the

text: habitable zone

text: s of their stars". This means there are "two billion" of these "Earth analogs" in the Milky Way alone. The JPL astronomers also noted that there are "50 billion other galaxies", potentially yielding more than one

text: sextillion

text: "Earth analog" planets if all galaxies have similar numbers of planets to the Milky Way.

text: Hodge is author or co-author of over 550 research papers and talks at professional meetings, as well as 28 books. Most of the papers are concerned with the extragalactic universe, especially nearby galaxies, their distances and their histories. Work on the Magellanic Clouds, carried out at observatories in South Africa, Australia and Chile, included a study of young stellar associations, of which he and his students published the first catalog. With colleague F. W. Wright, he published two widely used atlases of the Magellanic Clouds. He was the first to study the structure of the Local Group dwarf galaxies  and carried out the first large-scale survey of star-forming regions (HII regions) in spiral galaxies, in which he and his students mapped a total of 13011 of these objects. He and his former student, K. Krienke, have discovered 652 star clusters in the Andromeda Galaxy (M31).

text: Hodge is author or co-author of over 550 research papers and talks at professional meetings, as well as 28 books. Most of the papers are concerned with the extragalactic universe, especially nearby galaxies, their distances and their histories. Work on the

text: Magellanic Clouds

text: , carried out at observatories in

text: South Africa

text: Australia

text: and

text: Chile

text: , included a study of young

text: stellar associations

text: , of which he and his students published the first catalog. With colleague

text: F. W. Wright

text: , he published two widely used atlases of the

text: Magellanic Clouds

text: . He was the first to study the structure of the

text: Local Group

text: dwarf galaxies

text: and carried out the first large-scale survey of star-forming regions (

text: HII regions

text: ) in

text: spiral galaxies

text: , in which he and his students mapped a total of 13011 of these objects. He and his former student,

text: K. Krienke

text: , have discovered 652 star clusters in the

text: Andromeda Galaxy

text: There are three major types of irregular galaxies:

text: HXMM01 has an extremely high rate of star formation of roughly , a rate that will cause the nascent galaxy to consume nearly all of its gas and dust within 200 million years. The observation has profound implications for our conception of the formation of giant elliptical galaxies—although the process of formation for dwarf ellipticals had already been determined through analyses of gas density in lower-mass galaxies, the formation of giant elliptical galaxies had eluded description until the discovery of HXMM01. By analyzing HXMM01's rapid rate of star formation, the discovery team was able to deduce that giant elliptical galaxies would be able to form in the Universe at a redshift of about 1.5, corresponding to a distance (and thus observed galactic age) of about 4 billion years.

text: HXMM01 has an extremely high rate of star formation of roughly , a rate that will cause the nascent galaxy to consume nearly all of its gas and dust within 200 million years. The observation has profound implications for our conception of the formation of giant elliptical galaxies—although the process of formation for

text: dwarf elliptical

text: s had already been determined through analyses of gas density in lower-mass galaxies, the formation of giant elliptical galaxies had eluded description until the discovery of HXMM01. By analyzing HXMM01's rapid rate of star formation, the discovery team was able to deduce that giant elliptical galaxies would be able to form in the Universe at a redshift of about 1.5, corresponding to a distance (and thus observed galactic age) of about 4 billion years.

text: An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure.

text: An irregular galaxy is a

text: galaxy

text: that does not have a distinct regular shape, unlike a

text: spiral

text: or an

text: elliptical galaxy

text: . Irregular galaxies do not fall into any of the regular classes of the

text: Hubble sequence

text: , and they are often chaotic in appearance, with neither a

text: nuclear bulge

text: nor any trace of

text: spiral arm

text: structure.

text: The Central Bulge contains Population II stars, which are old stars, devoid of metals, and have low surface temperatures. For this reason the central bulge glows an orange/red color. The disk of the galaxy is full of star formation, and Population I stars, which are metal-rich, with high surface temperatures, causing the disk to glow blue. Surrounding the galaxy is a halo that is made up of old Population II stars, as well as globular clusters, which are groups of Population II stars that are spherical in shape and contain roughly one million stars. Star formation takes place in the spiral arms of the galaxy. The rotation velocity of the galaxy is nearly uniform throughout the entire disk. The reason for this is due to an even bigger halo of postulated dark matter that extends beyond the size of the galaxy. This dark matter is to date made up of an unknown substance which radiates no light, and accounts for up to 90% of the mass in a total galaxy.

text: Many of these spiral galaxies are probably interacting with the low surface brightness galaxies in the field of view. In some cases, however, it may be difficult to determine whether the companion is physically near the spiral galaxy or whether the companion is a foreground/background source or a source on the edge of the spiral galaxy.

text: NGC 31 is a spiral galaxy located in the Phoenix constellation.

text: NGC 31 is a

text: spiral galaxy

text: located in the

text: Phoenix

text: constellation.

text: NGC 4696 is an elliptical galaxy. It lies around 150 million light years away in the constellation Centaurus. It is the brightest galaxy in the Centaurus Cluster, a large, rich cluster of galaxies in the constellation of the same name.  The galaxy is surrounded by many dwarf elliptical galaxies also located within the cluster.

text: NGC 4696 is an

text: elliptical galaxy

text: . It lies around 150 million light years away in the

text: constellation

text: Centaurus

text: . It is the brightest galaxy in the

text: Centaurus Cluster

text: , a large, rich

text: cluster of galaxies

text: in the constellation of the same name.  The galaxy is surrounded by many

text: dwarf elliptical galaxies

text: also located within the cluster.

text: About 54 globular clusters have been identified in this galaxy, but the actual number may be 122 or more. The confirmed clusters may be several billion years younger than globular clusters in the Milky Way, and cluster formation appears to have increased during the past 100 million years. This increase is correlated with an inflow of gas into the center of the galaxy. The ultraviolet emission of massive stars in this galaxy matches the level of similar stars in the Large Magellanic Cloud.

text: About 54

text: globular cluster

text: s have been identified in this galaxy, but the actual number may be 122 or more. The confirmed clusters may be several billion years younger than globular clusters in the Milky Way, and cluster formation appears to have increased during the past 100 million years. This increase is correlated with an inflow of gas into the center of the galaxy. The

text: ultraviolet

text: emission of massive stars in this galaxy matches the level of similar stars in the

text: Large Magellanic Cloud

text: Today, the physical processes that lead to the peculiarities seen in the Arp atlas are now well understood. A large number of the objects are interacting galaxies, including M51 (Arp 85), Arp 220, and the Antennae Galaxies (NGC 4038/NGC 4039, or Arp 244). A few of the galaxies are simply dwarf galaxies that do not have enough mass to produce enough gravity to allow the galaxies to form any cohesive structure. NGC 1569 (Arp 210) is an example of one of the dwarf galaxies in the atlas. A few other galaxies are radio galaxies. These objects contain active galactic nuclei that produce powerful jets of gas called radio jets. The atlas includes the nearby radio galaxies M87 (Arp 152) and Centaurus A (Arp 153).

text: Today, the physical processes that lead to the peculiarities seen in the Arp atlas are now well understood. A large number of the objects are

text: interacting galaxies

text: , including

text: M51 (Arp 85)

text: Arp 220

text: , and

text: the Antennae Galaxies (NGC 4038/NGC 4039, or Arp 244)

text: . A few of the galaxies are simply

text: dwarf galaxies

text: that do not have enough

text: mass

text: to produce enough

text: gravity

text: to allow the galaxies to form any cohesive structure.

text: NGC 1569 (Arp 210)

text: is an example of one of the dwarf galaxies in the atlas. A few other galaxies are

text: radio galaxies

text: . These objects contain

text: active galactic nuclei

text: that produce powerful jets of gas called

text: radio jets

text: . The atlas includes the nearby radio galaxies

text: M87 (Arp 152)

text: and

text: Centaurus A (Arp 153)

text: Several galaxies and star clusters are contained within Capricornus.  Messier 30 is a globular cluster located 1 degree south of the galaxy group NGC 7103. The constellation also harbors the wide spiral galaxy NGC 6907.

text: Several galaxies and star clusters are contained within Capricornus.

text: Messier 30

text: is a globular cluster located 1 degree south of the galaxy group NGC 7103. The constellation also harbors the wide spiral galaxy NGC 6907.

text: The galaxy has a huge envelope of hydrogen gas, with an apparent size measuring 68′ × 80′, which is far larger than the apparent size of the galaxy in visible light (5.5′ × 7.0′). IC 10 is also unusual in the respect that the visible part of the galaxy seems to rotate in a different direction than the outer envelope. It has a H II nucleus.

text: The galaxy has a huge envelope of

text: hydrogen

text: gas, with an apparent size measuring 68′ × 80′, which is far larger than the apparent size of the galaxy in visible light (5.5′ × 7.0′). IC 10 is also unusual in the respect that the visible part of the galaxy seems to rotate in a different direction than the outer envelope. It has a

text: H II

text: nucleus.

text: NGC 6745 (also known as UGC 11391) is an irregular galaxy about 206 million light-years (63.5 mega-parsecs) away in the constellation Lyra.  It is actually a triplet of galaxies in the process of colliding.

text: NGC 6745 (also known as UGC 11391) is an

text: irregular galaxy

text: about 206 million

text: light-year

text: s (63.5 mega-

text: parsec

text: s) away in the

text: constellation

text: Lyra

text: .  It is actually a triplet of galaxies in the process of

text: colliding

text: Classifying types of starburst galaxies is difficult since starburst galaxies do not represent a specific type in and of themselves. Starbursts can occur in disk galaxies, and irregular galaxies often exhibit knots of starburst spread throughout the irregular galaxy. Nevertheless, astronomers typically classify starburst galaxies based on their most distinct observational characteristics. Some of the categorizations include:

text: Classifying types of starburst galaxies is difficult since starburst galaxies do not represent a specific type in and of themselves. Starbursts can occur in

text: disk galaxies

text: , and

text: irregular galaxies

text: often exhibit knots of starburst spread throughout the irregular galaxy. Nevertheless, astronomers typically classify starburst galaxies based on their most distinct observational characteristics. Some of the categorizations include:

text: Mergers are also locations of extreme amounts of star formation. The star formation rate (SFR) during a major merger can reach thousands of solar masses worth of new stars each year, depending on the gas content of each galaxy and its redshift. Typical merger SFRs are less than 100 new solar masses per year. This is large compared to our Galaxy, which makes only a few (~2) new stars each year. Though stars almost never get close enough to actually collide in galaxy mergers, giant molecular clouds rapidly fall to the center of the galaxy where they collide with other molecular clouds.  These collisions then induce condensations of these clouds into new stars. We can see this phenomenon in merging galaxies in the nearby universe. Yet, this process was more pronounced during the mergers that formed most elliptical galaxies we see today, which likely occurred 1-10 billion years ago, when there was much more gas (and thus more molecular clouds) in galaxies. Also, away from the center of the galaxy gas clouds will run into each other producing shocks which stimulate the formation of new stars in gas clouds. The result of all this violence is that galaxies tend to have little gas available to form new stars after they merge. Thus if a galaxy is involved in a major merger, and then a few billion years pass, the galaxy will have very few young stars (see Stellar evolution) left. This is what we see in today's elliptical galaxies, very little molecular gas and very few young stars. It is thought that this is because elliptical galaxies are the end products of major mergers which use up the majority of gas during the merger, and thus further star formation after the merger is quenched.

text: Mergers are also locations of extreme amounts of

text: star formation

text: . The star formation rate (SFR) during a major merger can reach thousands of solar masses worth of new stars each year, depending on the gas content of each galaxy and its redshift. Typical merger SFRs are less than 100 new solar masses per year. This is large compared to our Galaxy, which makes only a few (~2) new stars each year. Though stars almost never get close enough to actually collide in galaxy mergers, giant

text: molecular clouds

text: rapidly fall to the center of the galaxy where they collide with other molecular clouds.  These collisions then induce condensations of these clouds into new stars. We can see this phenomenon in merging galaxies in the nearby universe. Yet, this process was more pronounced during the mergers that formed most elliptical galaxies we see today, which likely occurred 1-10 billion years ago, when there was much more gas (and thus more

text: molecular clouds

text: ) in galaxies. Also, away from the center of the galaxy gas clouds will run into each other producing shocks which stimulate the formation of new stars in gas clouds. The result of all this violence is that galaxies tend to have little gas available to form new stars after they merge. Thus if a galaxy is involved in a major merger, and then a few billion years pass, the galaxy will have very few young stars (see

text: Stellar evolution

text: ) left. This is what we see in today's elliptical galaxies, very little molecular gas and very few young stars. It is thought that this is because elliptical galaxies are the end products of major mergers which use up the majority of gas during the merger, and thus further star formation after the merger is quenched.

text: The Milky Way galaxy is about 100,000 light-years in diameter, and the Sun is about 25,000 light-years from the galactic center. The small common star UDF 2457 may be one of the farthest known stars inside the main body of the Milky Way.  Globular clusters (such as Messier 54 and NGC 2419) and stellar streams are located further out in the galactic halo.

text: The

text: Milky Way

text: galaxy is about 100,000

text: light-year

text: s in diameter, and the

text: Sun

text: is about 25,000 light-years from the

text: galactic center

text: . The small common star UDF 2457 may be one of the farthest known stars inside the main body of the Milky Way.

text: Globular cluster

text: s (such as

text: Messier 54

text: and

text: NGC 2419

text: ) and

text: stellar streams

text: are located further out in the

text: galactic halo

text: Stars,Star clusters,Galaxies,Galaxy clusters,Super clusters

text: One galaxy group located in Capricornus is HCG 87, a group of at least three galaxies located 400 million light-years from Earth (redshift 0.0296). It contains a large elliptical galaxy, a face-on spiral galaxy, and an edge-on spiral galaxy. The face-on spiral galaxy is experiencing abnormally high rates of star formation, indicating that it is interacting with one or both members of the group. Furthermore, the large elliptical galaxy and the edge-on spiral galaxy, both of which have active nuclei, are connected by a stream of stars and dust, indicating that they too are interacting. Astronomers predict that the three galaxies may merge millions of years in the future to form a giant elliptical galaxy.

text: One

text: galaxy group

text: located in Capricornus is

text: HCG 87

text: , a group of at least three galaxies located 400 million

text: light-years

text: from Earth (

text: redshift

text: 0.0296). It contains a large

text: elliptical galaxy

text: , a face-on

text: spiral galaxy

text: , and an edge-on spiral galaxy. The face-on spiral galaxy is experiencing abnormally high rates of

text: star formation

text: , indicating that it is

text: interacting

text: with one or both members of the group. Furthermore, the large elliptical galaxy and the edge-on spiral galaxy, both of which have

text: active nuclei

text: , are connected by a stream of stars and dust, indicating that they too are interacting. Astronomers predict that the three galaxies may

text: merge

text: millions of years in the future to form a giant elliptical galaxy.

text: So far, no clear example of a Bahcall–Wolf cusp has been found in any galaxy or star cluster.  This may be due in part to the difficulty of resolving such a feature.

text: So far, no clear example of a Bahcall–Wolf cusp has been found in any galaxy or star cluster.  This may be due in part to the difficulty of

text: resolving

text: such a feature.

text: From 2010–11, the headline sponsor was Galaxy. Prior to 2010, it was known as the British Book Awards and was promoted by the UK publishing industry trade journal Publishing News. It was also known as the Nibbies because of the golden nib-shaped trophy given to winners.

text: From 2010–11, the headline sponsor was

text: Galaxy

text: . Prior to 2010, it was known as the British Book Awards and was promoted by the

text: UK

text: publishing

text: industry trade journal Publishing News. It was also known as the Nibbies because of the golden

text: nib

text: -shaped trophy given to winners.

text: The visibility of diffuse objects such as star clusters and galaxies is much more strongly affected by light pollution than is that of planets and stars. Under typical dark conditions only a few such objects are visible. These include the Pleiades, h/χ Persei, the Andromeda galaxy, the Carina Nebula, the Orion Nebula, Omega Centauri, 47 Tucanae, the Ptolemy Cluster Messier 7 near the tail of Scorpius and the globular cluster M13 in Hercules. The Triangulum Galaxy (M33) is a difficult averted vision object and only visible at all if it is higher than 50° in the sky. The globular clusters M 3 in Canes Venatici and M 92 in Hercules are also visible with the naked eye under such conditions. Under really dark sky conditions, however, M33 is easy to see, even in direct vision. Many other Messier objects are also visible under such conditions. The most distant objects that have been seen by the naked eye are nearby bright galaxies such as Centaurus A, Bode's Galaxy, Sculptor Galaxy, and Messier 83.

text: The visibility of diffuse objects such as

text: star cluster

text: s and galaxies is much more strongly affected by light pollution than is that of planets and stars. Under typical dark conditions only a few such objects are visible. These include the

text: Pleiades

text: h/χ Persei

text: , the

text: Andromeda galaxy

text: , the

text: Carina Nebula

text: , the

text: Orion Nebula

text: Omega Centauri

text: 47 Tucanae

text: , the Ptolemy Cluster

text: Messier 7

text: near the tail of

text: Scorpius

text: and the

text: globular cluster M13

text: in

text: Hercules

text: . The

text: Triangulum Galaxy (M33)

text: is a difficult

text: averted vision

text: object and only visible at all if it is higher than 50° in the sky. The globular clusters

text: M 3

text: in

text: Canes Venatici

text: and

text: M 92

text: in Hercules are also visible with the naked eye under such conditions. Under really dark sky conditions, however, M33 is easy to see, even in direct vision. Many other

text: Messier objects

text: are also visible under such conditions. The most distant objects that have been seen by the naked eye are nearby bright galaxies such as

text: Centaurus A

text: Bode's Galaxy

text: Sculptor Galaxy

text: , and

text: Messier 83

text: In 1750 Thomas Wright, in his work An original theory or new hypothesis of the Universe, correctly speculated that the Milky Way might be a body of a huge number of stars held together by gravitational forces rotating about a Galactic Center, akin to the solar system but on a much larger scale. The resulting disk of stars can be seen as a band on the sky from our perspective inside the disk. In a treatise in 1755, Immanuel Kant elaborated on Wright's idea about the structure of the Milky Way. At the time, the existence of other galaxies had not been discovered.

text: In 1750

text: Thomas Wright

text: , in his work An original theory or new hypothesis of the Universe, correctly speculated that the

text: Milky Way

text: might be a body of a huge number of stars held together by

text: gravitational forces

text: rotating about a

text: Galactic Center

text: , akin to the solar system but on a much larger scale. The resulting disk of stars can be seen as a band on the sky from our perspective inside the disk. In a treatise in 1755,

text: Immanuel Kant

text: elaborated on Wright's idea about the structure of the Milky Way. At the time, the existence of other galaxies had not been discovered.

text: A spiral galaxy is organized into a flat, rotating disk, usually with a prominent bulge or bar at the center, and trailing bright arms that spiral outward. The arms are dusty regions of star formation within which massive young stars produce a blue tint. Spiral galaxies are typically surrounded by a halo of older stars. Both the Milky Way and our nearest galaxy neighbor, the Andromeda Galaxy, are spiral galaxies.

text: A spiral galaxy is organized into a flat, rotating disk, usually with a prominent bulge or bar at the center, and trailing bright arms that spiral outward. The arms are dusty regions of star formation within which massive young stars produce a blue tint. Spiral galaxies are typically surrounded by a halo of older stars. Both the

text: Milky Way

text: and our nearest galaxy neighbor, the

text: Andromeda Galaxy

text: , are spiral galaxies.

text: In a comprehensive 1982 paper, R. Brent Tully presented the conclusions of his research concerning the basic structure of the LS. It consists of two components: an appreciably flattened disk containing two-thirds of the supercluster's luminous galaxies, and a roughly spherical halo containing the remaining one-third.The disk itself is a thin (~1 Mpc) ellipsoid with a long axis / short axis ratio of at least 6 to 1, and possibly as high as 9 to 1.Data released in June 2003 from the 5-year Two-degree-Field Galaxy Redshift Survey (2dF) has allowed astronomers to compare the LS to other superclusters. The LS represents a typical poor (that is, lacking a high density core) supercluster of rather small size. It has one rich galaxy cluster in the center, surrounded by filaments of galaxies and poor groups.The Local Group is located on the outskirts of the LS in a small filament extending from the Fornax Cluster to the Virgo Cluster. The Virgo Supercluster's volume is very approximately 7000 times that of the Local Group or 100 billion times that of the Milky Way. See volumes of similar orders of magnitude.

text: In a comprehensive 1982 paper,

text: R. Brent Tully

text: presented the conclusions of his research concerning the basic structure of the LS. It consists of two components: an appreciably flattened disk containing two-thirds of the supercluster's luminous galaxies, and a roughly spherical halo containing the remaining one-third.The disk itself is a thin (~1

text: Mpc

text: ) ellipsoid with a long axis / short axis ratio of at least 6 to 1, and possibly as high as 9 to 1.Data released in June 2003 from the 5-year

text: Two-degree-Field Galaxy Redshift Survey (2dF)

text: has allowed astronomers to compare the LS to other superclusters. The LS represents a typical poor (that is, lacking a high density core) supercluster of rather small size. It has one rich galaxy cluster in the center, surrounded by filaments of galaxies and poor groups.The

text: Local Group

text: is located on the outskirts of the LS in a small filament extending from the

text: Fornax Cluster

text: to the

text: Virgo Cluster

text: . The Virgo Supercluster's volume is very approximately 7000 times that of the Local Group or 100 billion times that of the Milky Way. See

text: volumes of similar orders of magnitude

text: NGC 2841 is a giant spiral galaxy with properties similar to those of the Andromeda Galaxy. It is a prototypical flocculent spiral galaxy, a type of spiral galaxy whose arms are patchy and discontinuous.

text: NGC 2841 is a giant spiral galaxy with properties similar to those of the

text: Andromeda Galaxy

text: . It is a prototypical

text: flocculent spiral galaxy

text: , a type of spiral galaxy whose arms are patchy and discontinuous.

text: Galaxy-galaxy lensing is a specific type of weak (and occasionally strong) gravitational lensing, in which the foreground object responsible for distorting the shapes of background galaxies is itself an individual field galaxy (as opposed to a galaxy cluster or the large-scale structure of the cosmos).  Of the three typical mass regimes in weak lensing, galaxy-galaxy lensing produces a "mid-range" signal (shear correlations of ~1%) that is weaker than the signal due to cluster lensing, but stronger than the signal due to cosmic shear.

text: Galaxy-galaxy lensing is a specific type of weak (and occasionally strong)

text: gravitational lensing

text: , in which the foreground object responsible for distorting the shapes of background galaxies is itself an individual

text: field galaxy

text: (as opposed to a

text: galaxy cluster

text: or the

text: large-scale structure of the cosmos

text: ).  Of the three typical mass regimes in weak lensing, galaxy-galaxy lensing produces a "mid-range" signal (shear correlations of ~1%) that is weaker than the signal due to cluster lensing, but stronger than the signal due to cosmic shear.

text: Doppler shift studies of galaxy clusters by Fritz Zwicky in 1937 found that most galaxies were moving much faster than seemed to be possible from what was known about the mass of the cluster. Zwicky hypothesized that there must be a great deal of non-luminous matter in the galaxy clusters, which became known as dark matter. Since his discovery, astronomers have determined that a large portion of galaxies (and most of the universe) is made up of dark matter. In 2003, however, four galaxies (NGC 821, NGC 3379, NGC 4494, and NGC 4697) were found to have little to no dark matter influencing the motion of the stars contained within them; the reason behind the lack of dark matter is unknown.

text: Doppler shift studies of

text: galaxy cluster

text: s by

text: Fritz Zwicky

text: in 1937 found that most galaxies were moving much faster than seemed to be possible from what was known about the mass of the cluster. Zwicky hypothesized that there must be a great deal of non-luminous matter in the galaxy clusters, which became known as

text: dark matter

text: . Since his discovery, astronomers have determined that a large portion of galaxies (and most of the universe) is made up of dark matter. In 2003, however, four galaxies (NGC 821,

text: NGC 3379

text: , NGC 4494, and

text: NGC 4697

text: ) were found to have little to no dark matter influencing the motion of the stars contained within them; the reason behind the lack of dark matter is unknown.

text: A Type II supernova (plural: supernovae or supernovas) results from the rapid collapse and violent explosion of a massive star. A star must have at least 8 times, and no more than 40–50 times, the mass of the Sun () to undergo this type of explosion. It is distinguished from other types of supernovae by the presence of hydrogen in its spectrum. Type II supernovae are mainly observed in the spiral arms of galaxies and in H II regions, but not in elliptical galaxies.

text: A Type II supernova (plural: supernovae or supernovas) results from the rapid collapse and violent explosion of a massive

text: star

text: . A star must have at least 8 times, and no more than 40–50 times, the

text: mass of the Sun

text: () to undergo this type of explosion. It is distinguished from other types of

text: supernova

text: e by the presence of hydrogen in its

text: spectrum

text: . Type II supernovae are mainly observed in the

text: spiral arm

text: s of

text: galaxies

text: and in

text: H II region

text: s, but not in

text: elliptical galaxies

text: Theorized in 1988, and observed in 2005, there are stars moving faster than the escape velocity of the Milky Way, and are traveling out into intergalactic space. There are several theories for their existence. One of the mechanisms would be that the supermassive black hole at the center of the Milky Way ejects stars from the galaxy at a rate of about one every hundred thousand years. Another theorized mechanism might be a supernova explosion in a binary system.

text: Theorized in 1988, and observed in 2005, there are stars moving faster than the

text: escape velocity

text: of the Milky Way, and are traveling out into intergalactic space. There are several

text: theories for their existence

text: . One of the mechanisms would be that the

text: supermassive black hole

text: at the center of the

text: Milky Way

text: ejects stars from the galaxy at a rate of about one every hundred thousand years. Another theorized mechanism might be a supernova explosion in a binary system.

text: Scorpius regularly argues that the Peacekeepers are essentially the only thing protecting  the rest of the Milky Way Galaxy from being killed or enslaved by the Scarran Empire, which he thinks justifies their adoption of draconian measures.

text: DDO 75 (also known as Sextans A, PGC 29653 or UGCA 205) is an irregular galaxy located in the constellation Sextans, same as its neighbour DDO 70 (Sextans B). When it is observed from Earth, it appears as a square in shape.

text: DDO 75

text: (also known as

text: Sextans

text: A,

text: PGC

text: 29653 or

text: UGCA

text: 205) is an

text: irregular galaxy

text: located in the

text: constellation

text: Sextans

text: , same as its neighbour

text: DDO 70

text: Sextans B

text: ). When it is observed from

text: Earth

text: , it appears as a

text: square

text: in

text: shape

text: A typical marlin lure is a small (), medium () to large ( or more) artificial with a shaped plastic or metal head to which a plastic skirt is attached. The design of the lure head, particularly its face, gives the lure its individual action when trolled through the water. Lure actions range from an active side-to-side swimming pattern to pushing water aggressively on the surface to, most commonly, tracking along in a straight line with a regular surface pop and bubble trail. Besides the shape, weight, and size of the lure head, the length and thickness of skirting, the number and size of hooks, and the length and size of the leader used in lure rigging all influence the action of the lure: how actively it will run and how it will respond to different sea conditions. Experienced anglers often fine-tune their lures to get the action they want.

text: The Antlia Dwarf is located about  away, in the constellation Antlia. Its distance from the barycenter of the Local Group is about 1.7 Mpc. At this distance, it is situated well outside the Local Group and is a member of a separate group of dwarf galaxies called Antlia Group. The Antlia Dwarf is separated from the small spiral/irregular galaxy NGC 3109 by only 1.18 degrees on the sky, which corresponds to a physical separation of  to  depending on their radial separation.

text: The Antlia Dwarf is located about  away, in the constellation

text: Antlia

text: . Its distance from the

text: barycenter

text: of the Local Group is about 1.7 Mpc. At this distance, it is situated well outside the

text: Local Group

text: and is a member of a separate group of dwarf galaxies called Antlia Group. The Antlia Dwarf is separated from the small spiral/irregular galaxy

text: NGC 3109

text: by only 1.18 degrees on the sky, which corresponds to a physical separation of  to  depending on their radial separation.

text: cD galaxies are similar to lenticular galaxies (S0) or elliptical galaxies (E#), but many times larger, some having envelopes that exceed one million light years in radius. They appear elliptical-like, with large low surface brightness envelopes. It is currently thought that cD's are the result of galaxy mergers. Some cD's have multiple galactic nuclei. cD galaxies are one of the types frequently found to be the brightest cluster galaxy (BCG) of a cluster. Many fossil group galaxies are similar to cD BCG galaxies, leading some to theorize that the cD results from the creation of a fossil group, and then the new cluster accumulating around the fossil group. However, cD's themselves are not found as field galaxies, unlike fossil groups. cD's form around 20% of BCGs.

text: cD galaxies are similar to

text: lenticular galaxies

text: (S0) or

text: elliptical galaxies

text: (E#), but many times larger, some having envelopes that exceed one million

text: light year

text: s in radius. They appear elliptical-like, with large low surface brightness envelopes. It is currently thought that cD's are the result of

text: galaxy merger

text: s. Some cD's have multiple

text: galactic nuclei

text: . cD galaxies are one of the types frequently found to be the

text: brightest cluster galaxy

text: (BCG) of a cluster. Many

text: fossil group galaxies

text: are similar to cD BCG galaxies, leading some to theorize that the cD results from the creation of a fossil group, and then the new cluster accumulating around the fossil group. However, cD's themselves are not found as

text: field galaxies

text: , unlike fossil groups. cD's form around 20% of BCGs.

text: The Hubble classification system rates elliptical galaxies on the basis of their ellipticity, ranging from E0, being nearly spherical, up to E7, which is highly elongated. These galaxies have an ellipsoidal profile, giving them an elliptical appearance regardless of the viewing angle. Their appearance shows little structure and they typically have relatively little interstellar matter. Consequently, these galaxies also have a low portion of open clusters and a reduced rate of new star formation. Instead they are dominated by generally older, more evolved stars that are orbiting the common center of gravity in random directions. The stars contain low abundances of heavy elements because star formation ceases after the initial burst. In this sense they have some similarity to the much smaller globular clusters.

text: The Hubble classification system rates elliptical galaxies on the basis of their ellipticity, ranging from E0, being nearly spherical, up to E7, which is highly elongated. These galaxies have an

text: ellipsoid

text: al profile, giving them an elliptical appearance regardless of the viewing angle. Their appearance shows little structure and they typically have relatively little

text: interstellar matter

text: . Consequently, these galaxies also have a low portion of

text: open cluster

text: s and a reduced rate of new star formation. Instead they are dominated by generally older, more

text: evolved stars

text: that are orbiting the common center of gravity in random directions. The stars contain low abundances of heavy elements because star formation ceases after the initial burst. In this sense they have some similarity to the much smaller

text: globular cluster

text: s.

text: There are many other galaxies located in Hydra. NGC 3314, usually delineated as NGC 3314a and NGC 3314b, is a pair of galaxies that appear superimposed, despite the fact that they are not related or interacting in any way. The foreground galaxy, NGC 3314a, is at a distance of 140 million light-years, and is a face-on spiral galaxy. The background galaxy, NGC 3314b, is an oblique spiral galaxy, and has a nucleus that appears reddened because of NGC 3314a's dusty disk. ESO 510-G13 is a warped spiral galaxy located 150 million light-years from Earth. Though most galactic disks are flat because of their rate of rotation, their conformation can be changed, as is the case with this galaxy. Astronomers speculate that this is due to interactions with other galaxies. NGC 5068 may be a member of the M83 group, but its identity is disputed. It has a low surface brightness and has a diameter of 4.5 arcminutes. It is not perfectly circular, rather, it is elliptical and oriented on a west-northwest/east-southeast axis. However, it is of fairly uniform brightness throughout.

text: There are many other galaxies located in Hydra.

text: NGC 3314

text: , usually delineated as NGC 3314a and NGC 3314b, is a pair of galaxies that appear superimposed, despite the fact that they are not related or interacting in any way. The foreground galaxy, NGC 3314a, is at a distance of 140 million light-years, and is a face-on spiral galaxy. The background galaxy, NGC 3314b, is an oblique spiral galaxy, and has a nucleus that appears reddened because of NGC 3314a's dusty disk.

text: ESO 510-G13

text: is a warped

text: spiral galaxy

text: located 150 million light-years from Earth. Though most galactic disks are flat because of their rate of rotation, their conformation can be changed, as is the case with this galaxy. Astronomers speculate that this is due to

text: interactions

text: with other galaxies.

text: NGC 5068

text: may be a member of the M83 group, but its identity is disputed. It has a low surface brightness and has a diameter of 4.5 arcminutes. It is not perfectly circular, rather, it is elliptical and oriented on a west-northwest/east-southeast axis. However, it is of fairly uniform brightness throughout.

text: Samsung Galaxy (stylized as SAMSUNG Galaxy, previously Samsung GALAXY) is a series of mobile computing devices designed, manufactured and marketed by Samsung Electronics. The product line includes the Galaxy S series of high-end smartphones, the Galaxy Tab series of tablets, the Galaxy Note series of tablets and phablets with the added functionality of a stylus, and the first version of the Galaxy Gear smartwatch, with later versions dropping the Galaxy branding.

text: Samsung Galaxy (stylized as SAMSUNG Galaxy, previously Samsung GALAXY) is a series of

text: mobile computing

text: devices designed, manufactured and marketed by

text: Samsung Electronics

text: . The product line includes the

text: Galaxy S series

text: of high-end

text: smartphones

text: , the

text: Galaxy Tab series

text: of

text: tablets

text: , the

text: Galaxy Note series

text: of tablets and

text: phablet

text: s with the added functionality of a stylus, and the first version of the

text: Galaxy Gear

text: smartwatch

text: , with later versions dropping the Galaxy branding.

text: The distinction between the halo and the main body of the galaxy is clearest in spiral galaxies, where the spherical shape of the halo contrasts with the flat disc.  In an elliptical galaxy, there is no sharp transition between the body of the galaxy and the halo.

text: The distinction between the halo and the main body of the galaxy is clearest in

text: spiral galaxies

text: , where the spherical shape of the halo contrasts with the flat

text: disc

text: .  In an

text: elliptical galaxy

text: , there is no sharp transition between the body of the galaxy and the halo.

text: NGC 5034 is a spiral galaxy of indeterminate type.

text: NGC 5034 is a

text: spiral

text: galaxy

text: of indeterminate type.

text: Examination of M87 at far infrared wavelengths shows an excess emission at wavelengths longer than 25 μm. Normally such emission may be an indication of thermal emission by warm dust. However, in the case of M87, the emission appears to be fully explained by synchrotron radiation from the jet. Within the galaxy, silicate grains are expected to survive for no more than 46 million years because of the X-ray emission from the core. This dust may be destroyed by the hostile environment or expelled from the galaxy. The combined mass of dust in this galaxy is no more than 70,000 times the mass of the Sun. By comparison, the Milky Way contains about a hundred million (10) solar masses worth of dust.

text: Examination of M87 at far

text: infrared

text: wavelengths shows an excess emission at wavelengths longer than 25 μm. Normally such emission may be an indication of

text: thermal emission

text: by warm dust. However, in the case of M87, the emission appears to be fully explained by

text: synchrotron radiation

text: from the jet. Within the galaxy, silicate grains are expected to survive for no more than 46 million years because of the X-ray emission from the core. This dust may be destroyed by the hostile environment or expelled from the galaxy. The combined mass of dust in this galaxy is no more than 70,000 times the

text: mass of the Sun

text: . By comparison, the Milky Way contains about a hundred million (10) solar masses worth of dust.

text: Rival Android smartphones released in 2011 such as the Samsung Galaxy SII did lag behind the 300 PPI mark due to their 800 x 400 or qHD (960 x 540) resolutions, but by 2012 phones such as the Samsung Galaxy SIII and HTC One X achieved it with HD (720p) displays around 5-inches, and by 2013 the 300+ PPI mark was found on midrange phones such as the Moto G. From 2013-14, many flagship devices such as the Samsung Galaxy S4 and HTC One (M8) had 1080p (FHD) screens around 5-inches for a 400+ PPI which surpassed the Retina density on the iPhone 5. The latest major redesign of the iPhone, the iPhone 6, has a 1334 x 750 resolution on a 4.7-inch screen, while rivals such as the Samsung Galaxy S6 have a QHD display of 2560 x 1440 resolution, close to four times the number of pixels found in the iPhone 6, giving the S6 a 577 PPI that is almost twice that of the iPhone 6's 326 PPI. The larger iPhone 6 Plus features a "Retina HD Display", which is a 5.5-inch 1080p screen with 401 PPI, which barely meets or lags behind Android phablet rivals such as the OnePlus One and Samsung Galaxy Note 4. Aside from resolution, all generations of iPhone Retina displays receive high ratings for other aspects such as brightness and color accuracy, compared to those of contemporary smartphones, while some Android devices such as the LG G3 have sacrificed screen quality and battery life for high resolution. Ars Technica suggested the "superfluousness of so many flagship phone features—the move from 720p to 1080p to 1440p and beyond...things are all nice to have, but you’d be hard-pressed to argue that any of them are essential". Furthermore, developers can better optimize content for iOS due to Apple's few screen sizes in contrast to Android's wide display format variations.

text: Rival Android smartphones released in 2011 such as the

text: Samsung Galaxy SII

text: did lag behind the 300 PPI mark due to their 800 x 400 or qHD (960 x 540) resolutions, but by 2012 phones such as the

text: Samsung Galaxy SIII

text: and

text: HTC One X

text: achieved it with HD (720p) displays around 5-inches, and by 2013 the 300+ PPI mark was found on midrange phones such as the

text: Moto G

text: . From 2013-14, many flagship devices such as the

text: Samsung Galaxy S4

text: and

text: HTC One (M8)

text: had 1080p (FHD) screens around 5-inches for a 400+ PPI which surpassed the Retina density on the

text: iPhone 5

text: . The latest major redesign of the iPhone, the

text: iPhone 6

text: , has a 1334 x 750 resolution on a 4.7-inch screen, while rivals such as the

text: Samsung Galaxy S6

text: have a QHD display of 2560 x 1440 resolution, close to four times the number of pixels found in the iPhone 6, giving the S6 a 577 PPI that is almost twice that of the iPhone 6's 326 PPI. The larger

text: iPhone 6 Plus

text: features a "Retina HD Display", which is a 5.5-inch 1080p screen with 401 PPI, which barely meets or lags behind Android

text: phablet

text: rivals such as the

text: OnePlus One

text: and

text: Samsung Galaxy Note 4

text: . Aside from resolution, all generations of iPhone Retina displays receive high ratings for other aspects such as brightness and color accuracy, compared to those of contemporary smartphones, while some Android devices such as the

text: LG G3

text: have sacrificed screen quality and battery life for high resolution. Ars Technica suggested the "superfluousness of so many flagship phone features—the move from 720p to 1080p to 1440p and beyond...things are all nice to have, but you’d be hard-pressed to argue that any of them are essential". Furthermore, developers can better optimize content for iOS due to Apple's few screen sizes in contrast to Android's wide display format variations.

text: One study found that large galaxies merged with each other on average once over the past 9 billion years. Small galaxies were coalescing with large galaxies more frequently. Note that the Milky Way and the Andromeda Galaxy are thought to collide in about 4.5 billion years.  The merging of these galaxies would classify as major as they have similar sizes. The result would therefore be an elliptical galaxy.

text: One study found that large galaxies merged with each other on average once over the past 9 billion years. Small galaxies were coalescing with large galaxies more frequently. Note that the

text: Milky Way

text: and the

text: Andromeda Galaxy

text: are thought to

text: collide in about 4.5 billion years

text: .  The merging of these galaxies would classify as major as they have similar sizes. The result would therefore be an

text: elliptical galaxy

text: Other possible members galaxies (galaxies listed in only one or two of the lists from the above references) include the irregular galaxies UGC 891, UGC 1104, UGC 1171, UGC 1175, and UGCA 20.

text: Other possible members galaxies (galaxies listed in only one or two of the lists from the above references) include the irregular galaxies

text: UGC 891

text: UGC 1104

text: UGC 1171

text: UGC 1175

text: , and

text: UGCA 20

text: Dwarf elliptical galaxies have properties that are intermediate between those of regular elliptical galaxies and globular clusters.  Dwarf spheroidal galaxies appear to be a distinct class: their properties are more similar to those of irregulars and late spiral-type galaxies.

text: Dwarf elliptical galaxies

text: have properties that are intermediate between those of regular elliptical galaxies and

text: globular clusters

text: Dwarf spheroidal galaxies

text: appear to be a distinct class: their properties are more similar to those of irregulars and late spiral-type galaxies.

text: This is a metal-poor cluster, meaning the stars have a low abundance of elements other than hydrogen and helium—what astronomers term metallicity. As recently as 1995, it was considered the most metal-poor globular cluster in the Milky Way. The chemical abundances of the stars in NGC 5053 are more similar to those in the dwarf galaxy Sagittarius Dwarf Spheroidal Galaxy than to the Milky Way halo. Along with the kinematics of the globular cluster, this suggests that NGC 5053 may have been stripped from the dwarf galaxy.

text: This is a metal-poor cluster, meaning the stars have a low abundance of elements other than hydrogen and helium—what astronomers term

text: metallicity

text: . As recently as 1995, it was considered the most metal-poor globular cluster in the

text: Milky Way

text: . The chemical abundances of the stars in NGC 5053 are more similar to those in the dwarf galaxy

text: Sagittarius Dwarf Spheroidal Galaxy

text: than to the

text: Milky Way halo

text: . Along with the

text: kinematics

text: of the globular cluster, this suggests that NGC 5053 may have been stripped from the dwarf galaxy.

text: Boötes has two bright galaxies. NGC 5248 (Caldwell 45) is a type Sc galaxy (a variety of spiral galaxy) of magnitude 10.2. It measures 6.5 by 4.9 arcminutes. Fifty million light-years from Earth, NGC 5248 is a member of the Virgo Cluster of galaxies; it has dim outer arms and obvious H II regions, dust lanes, and young star clusters. NGC 5676 is another type Sc galaxy of magnitude 10.9. It measures 3.9 by 2.0 arcminutes. Other galaxies include NGC 5008, a type Sc emission-line galaxy, NGC 5548, a type S Seyfert galaxy, NGC 5653, a type S HII galaxy, NGC 5778 (also classified as NGC 5825), a type E galaxy that is the brightest of its cluster, NGC 5886, and NGC 5888, a type SBb galaxy. NGC 5698 is a barred spiral galaxy, notable for being the host of the 2005 supernova SN 2005bc, which peaked at magnitude 15.3.

text: Boötes has two bright galaxies.

text: NGC 5248

text: Caldwell

text: 45) is a

text: type Sc galaxy

text: (a variety of

text: spiral galaxy

text: ) of magnitude 10.2. It measures 6.5 by 4.9 arcminutes. Fifty million light-years from Earth, NGC 5248 is a member of the

text: Virgo Cluster

text: of galaxies; it has dim outer arms and obvious

text: H II region

text: s,

text: dust lane

text: s, and young

text: star cluster

text: s.

text: NGC 5676

text: is another type Sc galaxy of magnitude 10.9. It measures 3.9 by 2.0 arcminutes. Other galaxies include

text: NGC 5008

text: , a type Sc

text: emission-line galaxy

text: NGC 5548

text: , a type S

text: Seyfert galaxy

text: NGC 5653

text: , a type S HII galaxy,

text: NGC 5778

text: (also classified as NGC 5825), a type E galaxy that is the brightest of its cluster,

text: NGC 5886

text: , and

text: NGC 5888

text: , a type SBb galaxy.

text: NGC 5698

text: is a barred spiral galaxy, notable for being the host of the 2005 supernova

text: SN 2005bc

text: , which peaked at magnitude 15.3.

text: Collectively they are thought to make up about a quarter of all galaxies. Some irregular galaxies were once spiral or elliptical galaxies but were deformed by an uneven external gravitational force. Irregular galaxies may contain abundant amounts of gas and dust. This is not necessarily true for dwarf irregulars.

text: The Sagittarius Dwarf Spheroidal Galaxy is currently in the process of being consumed by the Milky Way and is expected to pass through it within the next 100 million years. The Sagittarius Stream is a stream of stars in polar orbit around the Milky Way leeched from the Sagittarius Dwarf. The Virgo Stellar Stream is a stream of stars that is believed to have once been an orbiting dwarf galaxy that has been completely distended by the Milky Way's gravity.

text: The Sagittarius Dwarf Spheroidal Galaxy is currently in the process of being

text: consumed

text: by the Milky Way and is expected to pass through it within the next 100 million years. The

text: Sagittarius Stream

text: is a stream of stars in polar orbit around the Milky Way leeched from the Sagittarius Dwarf. The

text: Virgo Stellar Stream

text: is a stream of stars that is believed to have once been an orbiting dwarf galaxy that has been completely distended by the Milky Way's gravity.

text: The largest galaxies are giant ellipticals. Many elliptical galaxies are believed to form due to the interaction of galaxies, resulting in a collision and merger. They can grow to enormous sizes (compared to spiral galaxies, for example), and giant elliptical galaxies are often found near the core of large galaxy clusters.

text: The largest galaxies are giant ellipticals. Many elliptical galaxies are believed to form due to the

text: interaction of galaxies

text: , resulting in a collision and merger. They can grow to enormous sizes (compared to spiral galaxies, for example), and giant elliptical galaxies are often found near the core of large galaxy clusters.

text: Using this information the shape of the Milky Way has been determined to be a spiral galaxy, though the exact number and position of the spiral arms is the subject of ongoing research.

text: Using this information the shape of the Milky Way has been determined to be a

text: spiral galaxy

text: , though the exact number and position of the spiral arms is the subject of ongoing research.

text: Acampe produce slow-growing, medium-sized vines that form very large vegetative masses in nature.  They are noted for their thick, leathery, distichous leaves. They produce fragrant small to medium-sized yellow flowers, barred with brown stripes, in a few to many-flowered racemose inflorescence. The brittle sepals and petals look alike. The ear-shaped, fringed, white labellum (lip) is saccate (sac-shaped) or has a spur, and has red markings at its base. The fleshy column is short and has two waxy pollinia.

text: Acampe produce slow-growing, medium-sized

text: vine

text: s that form very large vegetative masses in nature.  They are noted for their thick, leathery,

text: distichous

text: leaves

text: . They produce fragrant small to medium-sized yellow

text: flower

text: s, barred with brown stripes, in a few to many-flowered

text: racemose

text: inflorescence

text: . The brittle

text: sepal

text: s and

text: petal

text: s look alike. The ear-shaped, fringed, white

text: labellum

text: (lip) is

text: saccate

text: (sac-shaped) or has a spur, and has red markings at its base. The fleshy

text: column

text: is short and has two waxy

text: pollinia

text: The largest satellite galaxy of the Milky Way is the Large Magellanic Cloud.

text: The largest satellite galaxy of the

text: Milky Way

text: is the

text: Large Magellanic Cloud

text: of an elliptical galaxy varies as a function of apparent distance

text: of an

text: elliptical galaxy

text: varies as a function of apparent distance

text: NGC 247 is one of several galaxies that is gravitationally bound to the Sculptor Galaxy (NGC 253). These galaxies form a small core in the center of the Sculptor Group, which is one of the nearest groups of galaxies to the Milky Way. Most other galaxies associated with the Sculptor Group are only weakly gravitationally bound to this core.

text: NGC 247 is one of several galaxies that is gravitationally bound to the

text: Sculptor Galaxy

text: (NGC 253). These galaxies form a small core in the center of the

text: Sculptor Group

text: , which is one of the nearest

text: groups of galaxies

text: to the

text: Milky Way

text: . Most other galaxies associated with the Sculptor Group are only weakly gravitationally bound to this core.

text: Unlike most primitive rhinoceroses, the front teeth of Paraceratherium were reduced to a single pair of incisors in either jaw, which were large and conical, and have been described as tusks. The upper incisors pointed downwards; the lower ones were shorter and pointed forwards. Among known rhinoceroses, this arrangement is unique to Paraceratherium and the related Urtinotherium. The incisors may have been larger in males. The canine teeth otherwise found behind the incisors were lost. The incisors were separated from the row of cheek teeth by a large diastema (gap). This feature is found in mammals where the incisors and cheek teeth have different specialisations. The upper molars, except for the third upper molar that was V-shaped, had a pi-shaped (π) pattern and a reduced metastyle. The premolars only partially formed the pi pattern. Each molar was the size of a human fist; among mammals they were only exceeded in size by proboscideans, though they were small relative to the size of the skull. The lower cheek teeth were L-shaped, which is typical of rhinoceroses.

text: Unlike most primitive rhinoceroses, the front teeth of Paraceratherium were reduced to a single pair of incisors in either jaw, which were large and conical, and have been described as tusks. The upper incisors pointed downwards; the lower ones were shorter and pointed forwards. Among known rhinoceroses, this arrangement is unique to Paraceratherium and the related Urtinotherium. The incisors may have been larger in males. The

text: canine teeth

text: otherwise found behind the incisors were lost. The incisors were separated from the row of cheek teeth by a large

text: diastema

text: (gap). This feature is found in mammals where the incisors and cheek teeth have different specialisations. The upper molars, except for the third upper molar that was V-shaped, had a pi-shaped (π) pattern and a reduced

text: metastyle

text: . The premolars only partially formed the pi pattern. Each molar was the size of a human fist; among mammals they were only exceeded in size by proboscideans, though they were small relative to the size of the skull. The lower cheek teeth were L-shaped, which is typical of rhinoceroses.

text: The kinematic connection between spiral and lenticular galaxies is most clear when analyzing the Tully–Fisher relation for spiral and lenticular samples. If lenticular galaxies are an evolved stage of spiral galaxies then they should have a similar Tully–Fisher relation with spirals, but with an offset in the luminosity / absolute magnitude axis. This would result from brighter, redder stars dominating the stellar populations of lenticulars. An example of this effect can be seen in the adjacent plot. One can clearly see that the best-fit lines for the spiral galaxy data and the lenticular galaxy have the same slope (and thus follow the same Tully–Fisher relation), but are offset by ΔI ≈ 1.5. This implies that lenticular galaxies were once spiral galaxies but are now dominated by old, red stars.

text: These are mostly dwarf galaxies or poorly defined spiral galaxies (with the designation Sm) that have low surface brightnesses (i.e. they emit little light per unit area).  Low surface brightness galaxies are actually quite common. The exception is NGC 2857 (Arp 1), which is an Sc spiral galaxy (which means that it has a definite structure with loosely wound spiral arms and a faint but well-defined nucleus).

text: These are mostly dwarf galaxies or poorly defined spiral galaxies (with the designation Sm) that have low surface brightnesses (i.e. they emit little light per unit area).  Low surface brightness galaxies are actually quite common. The exception is

text: NGC 2857

text: (Arp 1), which is an Sc spiral galaxy (which means that it has a definite structure with loosely wound spiral arms and a faint but well-defined nucleus).

text: The term "particle" is usually applied differently to three classes of sizes. The term macroscopic particle, usually refers to particles much larger than atoms and molecules. These are usually abstracted as point-like particles, even though they have volumes, shapes, structures, etc. Examples of macroscopic particles would include powder, dust, sand, pieces of debris during a car accident, or even objects as big as the stars of a galaxy.

text: The term "particle" is usually applied differently to three classes of sizes. The term

text: macroscopic particle

text: , usually refers to particles much larger than

text: atom

text: s and

text: molecule

text: s. These are usually

text: abstracted

text: as

text: point-like particles

text: , even though they have volumes, shapes, structures, etc. Examples of macroscopic particles would include

text: powder

text: dust

text: sand

text: , pieces of

text: debris

text: during a

text: car accident

text: , or even objects as big as the

text: star

text: s of a

text: galaxy

text: Below is a list of notable spiral galaxies with their own articles. The classification column refers to the galaxy morphological classification used by astronomers to describe galaxy structure.

text: Below is a list of notable spiral galaxies with their own articles. The classification column refers to the

text: galaxy morphological classification

text: used by astronomers to describe galaxy structure.

text: BCGs are divided into various classes of galaxies: giant ellipticals (gE), D galaxies and cD galaxies. cD and D galaxies both exhibit an extended diffuse envelope surrounding an elliptical-like nucleus akin to regular elliptical galaxies. The light profiles of BCGs are often described by a Sersic surface brightness law, a double Sersic profile or a de Vaucouleurs law. The different parametrizations of the light profile of BCG's, as well as the faintness of the diffuse envelope lead to discrepancies in the reported values of the sizes of these objects.

text: BCGs are divided into various classes of galaxies:

text: giant ellipticals

text: (gE),

text: D galaxies

text: and

text: cD galaxies

text: . cD and D galaxies both exhibit an extended diffuse envelope surrounding an elliptical-like nucleus akin to regular elliptical galaxies. The light profiles of BCGs are often described by a

text: Sersic surface brightness law

text: , a double Sersic profile or a

text: de Vaucouleurs

text: law. The different parametrizations of the light profile of BCG's, as well as the faintness of the diffuse envelope lead to discrepancies in the reported values of the sizes of these objects.

text: Super star cluster (SSC) is a very large region of star formation thought to be the precursor of a globular cluster.

text: In some cases, the spectra show both broad and narrow permitted lines, which is why they are classified as an intermediate type between Type I and Type II, such as Type 1.5 Seyfert. The spectra of some of these galaxies have changed from Type 1.5 to Type II in a matter of a few years. However, the characteristic broad Hα emission line has rarely, if ever, disappeared. The origin of the differences between Type I and Type II Seyfert galaxies is not known yet. There are a few cases where galaxies have been identified as Type II only because the broad components of the spectral lines have been very hard to detect. It is believed by some that all Type II Seyferts are in fact Type I, where the broad components of the lines are impossible to detect because of the angle we are at with respect to the galaxy. Specifically, in Type I Seyfert galaxies, we observe the central compact source more or less directly, therefore sampling the high velocity clouds in the broad line emission region moving around the supermassive black hole thought to be at the center of the galaxy. By contrast, in Type II Seyfert galaxies, the active nuclei are obscured and only the colder outer regions located further away from the clouds' broad line emission region are seen. This theory is known as the "Unification scheme" of Seyfert galaxies. However, it is not yet clear if this hypothesis can explain all the observed differences between the two types.

text: In some cases, the spectra show both broad and narrow permitted lines, which is why they are classified as an intermediate type between Type I and Type II, such as Type 1.5 Seyfert. The spectra of some of these galaxies have changed from Type 1.5 to Type II in a matter of a few years. However, the characteristic broad

text: Hα

text: emission line has rarely, if ever, disappeared. The origin of the differences between Type I and Type II Seyfert galaxies is not known yet. There are a few cases where galaxies have been identified as Type II only because the broad components of the spectral lines have been very hard to detect. It is believed by some that all Type II Seyferts are in fact Type I, where the broad components of the lines are impossible to detect because of the angle we are at with respect to the galaxy. Specifically, in Type I Seyfert galaxies, we observe the central compact source more or less directly, therefore sampling the high velocity clouds in the broad line emission region moving around the supermassive black hole thought to be at the center of the galaxy. By contrast, in Type II Seyfert galaxies, the active nuclei are obscured and only the colder outer regions located further away from the clouds' broad line emission region are seen. This theory is known as the "Unification scheme" of Seyfert galaxies. However, it is not yet clear if this hypothesis can explain all the observed differences between the two types.

text: NGC 5258 is a spiral galaxy located in the constellation Virgo.  The galaxy is notably interacting with the spiral galaxy NGC 5257.  The two galaxies are listed together as Arp 240 in the Atlas of Peculiar Galaxies.  Both galaxies are distorted by the gravitational interaction, and both are connected by a tidal bridge, as can be seen in images of these galaxies.

text: NGC 5258 is a

text: spiral galaxy

text: located in the

text: constellation

text: Virgo

text: .  The galaxy is notably

text: interacting

text: with the spiral galaxy

text: NGC 5257

text: Arp 240

text: in the

text: Atlas of Peculiar Galaxies

text: In the De Vaucouleurs system for classifying galaxies, NGC 1614 has a galaxy morphological classification of SB(s)c pec. The SB indicates this is a barred spiral galaxy, while the '(s)' means it lacks a ring-like structure around the nucleus. The trailing 'c' describes the spiral arm structure as being loosely wound. The peculiar nature of the galaxy is noted with the 'pec.' abbreviation. The galaxy is bright at the center, with two nearly symmetrical inner spiral arms. It is a luminous infrared source, ranking 55th in the 2003 IRAS Revised Bright Galaxy Sample, and is the second most luminous galaxy within 75 Mpc.

text: In the

text: De Vaucouleurs system

text: for classifying galaxies, NGC 1614 has a

text: galaxy morphological classification

text: of SB(s)c pec. The SB indicates this is a

text: barred spiral galaxy

text: , while the '(s)' means it lacks a ring-like structure around the nucleus. The trailing 'c' describes the spiral arm structure as being loosely wound. The peculiar nature of the galaxy is noted with the 'pec.' abbreviation. The galaxy is bright at the center, with two nearly symmetrical inner spiral arms. It is a luminous infrared source, ranking 55th in the 2003 IRAS Revised Bright Galaxy Sample, and is the second most luminous galaxy within 75 Mpc.

text: Satellite galaxies that orbit from  of the edge of the disc of the Milky Way Galaxy to the edge of the dark matter halo of the Milky Way at  from the center of the galaxy, are generally depleted in hydrogen gas compared to those that orbit more distantly. The reason is the dense hot gas halo of the Milky Way, which strips cold gas from the satellites. Satellites beyond that region still retain copious quantities of gas.

text: Satellite galaxies that orbit from  of the edge of the

text: disc

text: of the Milky Way Galaxy to the edge of the

text: dark matter halo

text: of the Milky Way at  from the center of the galaxy, are generally depleted in hydrogen gas compared to those that orbit more distantly. The reason is the dense hot gas halo of the Milky Way, which strips cold gas from the satellites. Satellites beyond that region still retain copious quantities of gas.

text: A set of stars with similar space motion and ages is known as a kinematic group. These are stars that could share a common origin, such as the evaporation of an open cluster, the remains of a star forming region, or collections of overlapping star formation bursts at differing time periods in adjacent regions. Most stars are born within molecular clouds known as stellar nurseries. The stars formed within such a cloud compose gravitationally bound open clusters containing dozens to thousands of members with similar ages and compositions. These clusters dissociate with time. Groups of young stars that escape a cluster, or are no longer bound to each other, form stellar associations. As these stars age and disperse, their association is no longer readily apparent and they become moving groups of stars.

text: A set of stars with similar space motion and ages is known as a kinematic group. These are stars that could share a common origin, such as the evaporation of an

text: open cluster

text: , the remains of a star forming region, or collections of overlapping star formation bursts at differing time periods in adjacent regions. Most stars are born within

text: molecular cloud

text: s known as

text: stellar nurseries

text: . The stars formed within such a cloud compose gravitationally bound

text: open clusters

text: containing dozens to thousands of members with similar ages and compositions. These clusters dissociate with time. Groups of young stars that escape a cluster, or are no longer bound to each other, form stellar associations. As these stars age and disperse, their association is no longer readily apparent and they become moving groups of stars.

text: After only five months at Choice FM, he won his 1st best DJ award at the MOBO Awards ceremony, where he was approached by various radio stations. He left Choice FM to host a networked Sunday show on Galaxy FM and was offered the 9pm-1am time slot, following the stations headlining talent Hed Kandi. The popularity of his radio show quickly began to overtake competitive shows on other stations in the Rajarratings), where he quickly gained a large fan base. The Steve Sutherland Show quickly became one of the most popular urban shows in the United Kingdom. His show broadcast on the entire Galaxy Network (Galaxy Birmingham, Galaxy Manchester, Galaxy North East, Galaxy Scotland, Galaxy South Coast, Galaxy Yorkshire and Galaxy Digital).

text: After only five months at Choice FM, he won his 1st best DJ award at the

text: MOBO Awards

text: ceremony, where he was approached by various radio stations. He left Choice FM to host a networked Sunday show on

text: Galaxy FM

text: and was offered the 9pm-1am time slot, following the stations headlining talent

text: Hed Kandi

text: . The popularity of his radio show quickly began to overtake competitive shows on other stations in the

text: Rajar

text: ratings), where he quickly gained a large fan base. The

text: Steve Sutherland Show

text: quickly became one of the most popular urban shows in the United Kingdom. His show broadcast on the entire Galaxy Network (

text: Galaxy Birmingham

text: Galaxy Manchester

text: Galaxy North East

text: Galaxy Scotland

text: Galaxy South Coast

text: Galaxy Yorkshire

text: and

text: Galaxy Digital

text: The HDF galaxies contained a considerably larger proportion of disturbed and irregular galaxies than the local universe; galaxy collisions and mergers were more common in the young universe as it was much smaller than today. It is believed that giant elliptical galaxies form when spirals and irregular galaxies collide.

text: The HDF galaxies contained a considerably larger proportion of disturbed and irregular galaxies than the local universe; galaxy collisions and mergers were more common in the young universe as it was much smaller than today. It is believed that giant

text: elliptical galaxies

text: form when spirals and irregular galaxies collide.

text: As with many other rich galaxy clusters, Virgo's intracluster medium is filled with a hot, rarefied plasma at temperatures of 30 million Kelvin that emits X-Rays. Within the intracluster medium are found a large number of intergalactic stars (up to 10% of the stars in the cluster), including some planetary nebulae, that it is theorized were expelled from their home galaxies on interactions with other galaxies, as well as some globular clusters, possibly stripped off dwarf galaxies, and even at least one star formation region.

text: As with many other rich galaxy clusters, Virgo's

text: intracluster medium

text: is filled with a hot, rarefied

text: plasma

text: at temperatures of 30 million

text: Kelvin

text: that emits

text: X-Rays

text: . Within the intracluster medium are found a large number of

text: intergalactic star

text: s (up to 10% of the stars in the cluster), including some

text: planetary nebula

text: e, that it is theorized were expelled from their home galaxies on

text: interactions with other galaxies

text: , as well as some

text: globular cluster

text: s, possibly stripped off

text: dwarf galaxies

text: , and even at least one

text: star formation

text: region

text: This galaxy is presumed to be the primary location of the 2004-2009 science fiction television series Stargate Atlantis.  While it's mentioned the show takes place in "the Pegasus galaxy" it has not explicitly stated if it is the Irregular or Spheroidal. However, when the Pegasus galaxy has been seen from the Midway station an irregular galaxy is shown. Also, in the discussion regarding the new McKay–Carter Intergalactic Gate Bridge, General Hank Landry states that the distance between the Pegasus and Milky Way galaxies is "three million light-years", suggesting that the series takes place in the Pegasus Dwarf Irregular Galaxy.

text: This galaxy is presumed to be the primary location of the 2004-2009

text: science fiction

text: television series

text: Stargate Atlantis

text: .  While it's mentioned the show takes place in "the Pegasus galaxy" it has not explicitly stated if it is the Irregular or

text: Spheroidal

text: . However, when the Pegasus galaxy has been seen from the Midway station an irregular galaxy is shown. Also, in the discussion regarding the new

text: McKay–Carter Intergalactic Gate Bridge

text: , General

text: Hank Landry

text: Milky Way

text: galaxies is "three million light-years", suggesting that the series takes place in the Pegasus Dwarf Irregular Galaxy.

text: A disc is a component of disk galaxies, such as spiral galaxies, or lenticular galaxies.

text: A disc is a component of

text: disk galaxies

text: , such as

text: spiral galaxies

text: , or

text: lenticular galaxies

text: The type-cD galaxy (also cD-type galaxy, cD galaxy) is a galaxy morphology classification, a subtype of type-D giant elliptical galaxy. Characterized by a large halo of stars, they can be found near the centres of some rich galaxy clusters. They are also known as supergiant ellipticals or central dominant galaxies.

text: The type-cD galaxy (also cD-type galaxy, cD galaxy) is a

text: galaxy

text: morphology classification, a subtype of

text: type-D

text: giant

text: elliptical galaxy

text: . Characterized by a large

text: halo

text: of

text: star

text: s, they can be found near the centres of some rich

text: galaxy cluster

text: s. They are also known as supergiant ellipticals or central dominant galaxies.

text: The Sculptor Dwarf Irregular Galaxy and the dwarf galaxy UGCA 442 are both companions of the spiral galaxy NGC 7793.  These galaxies all lie within the Sculptor Group, a weakly bound, filament-like group of galaxies located near the Local Group.

text: The Sculptor Dwarf Irregular Galaxy and the

text: dwarf galaxy

text: UGCA 442

text: are both companions of the

text: spiral galaxy

text: NGC 7793

text: .  These galaxies all lie within the

text: Sculptor Group

text: , a weakly bound, filament-like

text: group of galaxies

text: located near the

text: Local Group

text: In episode 25, Kittan meets his demise by protecting the other members of Team Dai-Gurren. Super Galaxy Dai-Gurren, unable to escape the incredibly dense space sea produced by the Death Spiral Machine, is ordered by Simon to move towards the center of the sea, where the Machine rests surrounded by a powerful shield. After the ship's weapons fail to get anywhere near the shield, Kittan offers to take the Space King Kittan on a mission to destroy the shield and fire spiral-based missiles at the core of the Death Spiral Machine, but not before stealing a kiss from Yoko, and apologizing for "[his] selfishness". Though he successfully breaks through the shield, the Space King Kittan is crushed by the immense gravity of the space sea, leaving Team Dai-Gurren shocked at what they think is the death of Kittan. However, the original King Kittan, wielding one of the drills that broke off from the Gurren-Lagann when it was attempting to transform Super Galaxy Dai-Gurren into humanoid form, flies towards the Machine's core, screaming his final speech. Kittan awakens his own Spiral Energy, melding the drill to his King Kittan, and performing his own variation of the Giga Drill Breaker (King Kittan Giga Drill Break) to destroy the Death Spiral Machine. The resulting explosion engulfs and kills Kittan, who acknowledges his interest in Spiral energy before his demise, but also frees the Super Galaxy Dai-Gurren from the space sea, allowing Simon to transform it into Super Galaxy Gurren-Lagann and fulfill Kittan's dying wish.

text: Surface brightness fluctuation (SBF) is a secondary distance indicator used to estimate distances to galaxies.  It is useful to 100 Mpc (parsec).  The method measures the variance in a galaxy's light distribution arising from fluctuations in the numbers of and luminosities of individual stars per resolution element. The technique uses the fact that galaxies are made up of a finite number of stars.  The number of stars in any small patch of a galaxy will vary from point to point, creating a noise-like fluctuation in its surface brightness.  While the various stars present in a galaxy will cover an enormous range of luminosity, the SBF can be characterized as having an average brightness. A galaxy twice as far away appears twice as smooth as a result of the averaging. Older elliptical galaxies have fairly consistent stellar populations, thus it closely approximates a standard candle.  In practice, corrections are required to account for variations in age or metallicity from galaxy to galaxy. Calibration of the method is made empirically from Cepheids or theoretically from stellar population models.

text: Surface brightness fluctuation (SBF) is a secondary

text: distance indicator

text: used to estimate distances to galaxies.  It is useful to 100 Mpc (

text: parsec

text: ).  The method measures the variance in a galaxy's light distribution arising from fluctuations in the numbers of and luminosities of individual stars per resolution element. The technique uses the fact that galaxies are made up of a finite number of stars.  The number of stars in any small patch of a galaxy will vary from point to point, creating a noise-like fluctuation in its surface brightness.  While the various stars present in a galaxy will cover an enormous range of luminosity, the SBF can be characterized as having an average brightness. A galaxy twice as far away appears twice as smooth as a result of the averaging. Older

text: elliptical galaxies

text: have fairly consistent stellar populations, thus it closely approximates a

text: standard candle

text: .  In practice, corrections are required to account for variations in age or metallicity from galaxy to galaxy. Calibration of the method is made empirically from Cepheids or theoretically from stellar population models.

text: Roughly 80% of all galaxies located within  of the Milky Way in groups or clusters of galaxies. Most low-surface-brightness galaxies are field galaxies. The median Hubble-type of field galaxies is Sb, a type of spiral galaxy.

text: Roughly 80% of all galaxies located within  of the Milky Way in groups or clusters of galaxies. Most

text: low-surface-brightness galaxies

text: are field galaxies. The median Hubble-type of field galaxies is Sb, a type of

text: spiral galaxy

text: Interactions with nearby galaxies are thought to have influenced star formation in NGC 4449 and, in fact, in 2012 two small galaxies have been discovered interacting with this galaxy: a very low surface brightness disrupted dwarf spheroidal with the same stellar mass as NGC 4449's halo but with a ratio of dark matter to stellar matter between 5 and 10 times that of NGC 4449 and a highly flattened globular cluster with two tails of young stars that may be the nucleus of a gas-rich galaxy. Both satellites have apparently been disrupted by NGC 4449 and are now being absorbed by it.

text: Interactions with nearby galaxies are thought to have influenced star formation in NGC 4449 and, in fact, in 2012 two small galaxies have been discovered interacting with this galaxy: a very low

text: surface brightness

text: disrupted

text: dwarf spheroidal

text: with the same stellar mass as NGC 4449's

text: halo

text: but with a ratio of

text: dark matter

text: to stellar matter between 5 and 10 times that of NGC 4449 and a highly flattened

text: globular cluster

text: with two

text: tails

text: of young stars that may be the nucleus of a gas-rich galaxy. Both satellites have apparently been disrupted by NGC 4449 and are now being absorbed by it.

text: In all machining work, there are measurable amounts of difference between the design specification of an object, and its actual manufactured size. In locksmithing, the allowable tolerance is decided by the range of minute differences between a key's size and shape in comparison to the size and shape required to turn the tumblers within the lock. Key relevance is the measure of similarity between the key and the optimal size needed to fit the lock, or it is the similarity between a duplicate key and the original it is seeking to replicate.

text: Dwarf spiral galaxies, particularly the dwarf counterparts of Sa-Sc type spiral galaxies, are quite rare.  In contrast, dwarf elliptical galaxies, dwarf irregular galaxies, and the dwarf versions of Magellanic type galaxies (which may be considered transitory between spiral and irregular in terms of morphology) are very common.

text: Dwarf spiral galaxies, particularly the dwarf counterparts of

text: Sa-Sc type

text: spiral galaxies, are quite rare.  In contrast,

text: dwarf elliptical galaxies

text: , dwarf

text: irregular galaxies

text: , and the dwarf versions of

text: Magellanic type

text: galaxies (which may be considered transitory between spiral and irregular in terms of morphology) are very common.

text: The masses of stars clusters can be measured by integrating the stellar mass function.  Although only the most massive cluster members can be detected, the mass function can be estimated to lower levels and the cluster mass is calculated to be around .

text: The masses of stars clusters can be measured by

text: integrating

text: the stellar

text: mass function

text: .  Although only the most massive cluster members can be detected, the mass function can be estimated to lower levels and the cluster mass is calculated to be around .

text: ULAS J0015+01 has been thought to either be a remnant of the Milky Way's formation or a merge with a different galaxy. Analysis of the surrounding environment does not favor the presence of a star within such a place of low density important for star formation. Another explanation was that this star was part of a population of stars that was stripped from their parent galaxy by the Milky Way. If it were originally part of the Milky Way, it would have been ejected at a high velocity of around 600 km/s. Another hypothesis was it is part of an unknown galaxy with low surface brightness, but that seems unlikely. No other stars have been discovered past ULAS J0015+01 or ULAS J0744+25, which almost completely gets rid of the unknown galaxy hypothesis.

text: ULAS J0015+01 has been thought to either be a remnant of the Milky Way's formation or a merge with a different galaxy. Analysis of the surrounding environment does not favor the presence of a star within such a place of low density important for star formation. Another explanation was that this star was part of a

text: population of stars

text: that was stripped from their parent galaxy by the Milky Way. If it were originally part of the Milky Way, it would have been ejected at a high velocity of around 600 km/s. Another hypothesis was it is part of an unknown galaxy with low surface brightness, but that seems unlikely. No other stars have been discovered past ULAS J0015+01 or ULAS J0744+25, which almost completely gets rid of the unknown galaxy hypothesis.

text: HVGC-1 is the first discovered hypervelocity globular cluster. Discovered in 2014, it was found escaping the supergiant elliptical galaxy Messier 87, in the Virgo Cluster. It is one of thousands of globular clusters found in M87. It is the first hypervelocity star cluster so far discovered. The globular is located at decimal degrees (RA,DEC) (187.72791°,+12.68295°).

text: HVGC-1 is the first discovered

text: hypervelocity

text: globular cluster

text: . Discovered in 2014, it was found escaping the supergiant elliptical galaxy

text: Messier 87

text: , in the

text: Virgo Cluster

text: . It is one of thousands of

text: globular cluster

text: s found in M87. It is the first hypervelocity

text: star cluster

text: so far discovered. The globular is located at decimal degrees (RA,DEC) (187.72791°,+12.68295°).

text: The vimana (shrine) is at the back of the mantapa. Each side of the vimana measures 10.5 m and has five vertical sections. Each vertical section comprises a large double storeyed niche in the centre and two heavy pillar-like sections on either side. The two pillar-like sections adjoining the niche are rotated about their vertical axis to produce a star-shaped plan for the shrine. The pillar-like section and the niche bear many ornate sculptures, belonging to an earlier style. There are some sixty large sculptures of deities from both Vaishnava and Shaiva faiths. From the shape of the vimana it has been inferred that the tower above it would have been of the Bhumija style when it existed and not the regular star shaped tower that followed the shape of the vimana. The Bhumija towers, which are intact on the miniature shrines at the entrance of the hall are actually a type of nagara (North Indian) tower, being curvilinear in shape. This shape of tower is quite uncommon in pure dravidian architecture. The shrine has a life size (about 6 ft) image of Keshava (a form of Vishnu) with four hands. Each hand holds an attribute; the discus (chakra), the mace (gadha), the lotus-flower (padma) and the conch (Shanka), in clockwise direction. The entrance to the shrine is flanked by life size sculptures of door guardians (dvarapalaka).

text: The

text: vimana

text: (shrine) is at the back of the mantapa. Each side of the vimana measures 10.5 m and has five vertical sections. Each vertical section comprises a large double storeyed niche in the centre and two heavy pillar-like sections on either side. The two pillar-like sections adjoining the niche are rotated about their vertical axis to produce a star-shaped plan for the shrine. The pillar-like section and the niche bear many ornate sculptures, belonging to an earlier style. There are some sixty large sculptures of deities from both

text: Vaishnava

text: and

text: Shaiva

text: faiths. From the shape of the vimana it has been inferred that the tower above it would have been of the

text: Bhumija

text: style when it existed and not the regular star shaped tower that followed the shape of the vimana. The Bhumija towers, which are intact on the miniature shrines at the entrance of the hall are actually a type of nagara (North Indian) tower, being curvilinear in shape. This shape of tower is quite uncommon in pure

text: dravidian

text: architecture. The shrine has a life size (about 6 ft) image of Keshava (a form of Vishnu) with four hands. Each hand holds an attribute; the discus (chakra), the mace (gadha), the lotus-flower (padma) and the conch (Shanka), in clockwise direction. The entrance to the shrine is flanked by life size sculptures of door guardians (dvarapalaka).

text: Eggen's argument that groups of this type are in fact cluster remnants has been debated. It has been noted that because such phenomena may also be the result of other dynamical mechanisms. Famaey B, et al. report that about 85% of stars in the Hyades Stream have been shown to be completely unrelated to the original cluster on the grounds of dissimilar age and metallicity; their common motion is attributed to tidal effects of the massive rotating bar at the center of the Milky Way Galaxy.  Among the remaining members of the Hyades Stream, the exoplanet host star Iota Horologii has recently been proposed as an escaped member of the primordial Hyades Cluster.

text: Eggen's argument that groups of this type are in fact cluster remnants has been debated. It has been noted that because such phenomena may also be the result of other dynamical mechanisms. Famaey B, et al. report that about 85% of stars in the Hyades Stream have been shown to be completely unrelated to the original cluster on the grounds of dissimilar age and

text: metallicity

text: ; their common motion is attributed to tidal effects of the massive rotating

text: bar

text: at the center of the

text: Milky Way Galaxy

text: .  Among the remaining members of the Hyades Stream, the

text: exoplanet

text: host star

text: Iota Horologii

text: VISTA observations will support research in many astronomical areas. Within our galaxy, VISTA is expected to find many new brown dwarf stars and be able to test ideas about the nature of dark matter. One VISTA survey is designed to find and study huge numbers of variable stars in our galaxy by taking images of the same areas of sky at different times. Using VISTA data astronomers will be able to map the structure of our galaxy in much more detail than ever before. Another VISTA survey will study our neighbouring small galaxies, the Magellanic Clouds, and their surroundings. VISTA data will also be used to create a 3D map of about 5% of the entire observable Universe. Further out, VISTA will be a powerful tool for discovering remote quasars and studying the evolution of galaxies and clusters of galaxies. It will help to probe the nature of dark energy by finding very distant galaxy clusters.  Infrared measurements from the VVV astronomical survey have been employed to bolster the cosmic distance ladder, namely by providing reliable distances to star clusters and Cepheid variable stars.

text: VISTA observations will support research in many astronomical areas. Within our galaxy, VISTA is expected to find many new brown dwarf stars and be able to test ideas about the nature of dark matter. One VISTA survey is designed to find and study huge numbers of variable stars in our galaxy by taking images of the same areas of sky at different times. Using VISTA data astronomers will be able to map the structure of our galaxy in much more detail than ever before. Another VISTA survey will study our neighbouring small galaxies, the Magellanic Clouds, and their surroundings. VISTA data will also be used to create a 3D map of about 5% of the entire observable Universe. Further out, VISTA will be a powerful tool for discovering remote quasars and studying the evolution of galaxies and clusters of galaxies. It will help to probe the nature of dark energy by finding very distant galaxy clusters.

text: Infrared

text: measurements from the VVV astronomical survey have been employed to bolster the

text: cosmic distance ladder

text: , namely by providing reliable distances to

text: star clusters

text: and

text: Cepheid

text: variable stars

text: Many dwarf galaxies may orbit a single larger galaxy; the Milky Way has at least a dozen such satellites, with an estimated 300–500 yet to be discovered. Dwarf galaxies may also be classified as elliptical, spiral, or irregular. Since small dwarf ellipticals bear little resemblance to large ellipticals, they are often called dwarf spheroidal galaxies instead.

text: Many dwarf galaxies may orbit a single larger galaxy; the Milky Way has at least a dozen such satellites, with an estimated 300–500 yet to be discovered. Dwarf galaxies may also be classified as

text: elliptical

text: spiral

text: , or

text: irregular

text: . Since small dwarf ellipticals bear little resemblance to large ellipticals, they are often called

text: dwarf spheroidal galaxies

text: instead.

text: Before the advent of modern cosmology, there was considerable talk about the size and shape of the universe. In 1920, the famous Shapley-Curtis debate took place between Harlow Shapley and Heber D. Curtis over this issue. Shapley argued for a small universe the size of the Milky Way galaxy and Curtis argued that the Universe was much larger. The issue was resolved in the coming decade with Hubble's improved observations.

text: Before the advent of

text: modern cosmology

text: , there was considerable talk about the

text: size

text: and

text: shape

text: of the

text: universe

text: . In 1920, the famous

text: Shapley-Curtis debate

text: took place between

text: Harlow Shapley

text: and

text: Heber D. Curtis

text: over this issue. Shapley argued for a small universe the size of the

text: Milky Way galaxy

text: and Curtis argued that the Universe was much larger. The issue was resolved in the coming decade with Hubble's improved observations.

text: Lots can come in various sizes and shapes.  To be considered a single lot, the land described as the "lot" must be contiguous.  Two separate parcels are considered two lots, not one.  Often a lot is sized for a single house or other building.  Many lots are rectangular in shape, although other shapes are possible as long as the boundaries are well-defined.  Methods of determining or documenting the boundaries of lots include metes and bounds, quadrant method, and use of a plat diagram.  Use of the metes and bounds method may be compared to drawing a polygon.  Metes are points which are like the vertices (corners) of a polygon.  Bounds are line segments between two adjacent metes.  Bounds are usually straight lines, but can be curved as long as they are clearly defined.

text: Lots can come in various sizes and shapes.  To be considered a single lot, the land described as the "lot" must be contiguous.  Two separate parcels are considered two lots, not one.  Often a lot is sized for a single

text: house

text: or other building.  Many lots are rectangular in shape, although other shapes are possible as long as the boundaries are well-defined.  Methods of

text: determining or documenting the boundaries of lots

text: include

text: metes and bounds

text: quadrant method

text: , and use of a

text: plat

text: diagram.  Use of the metes and bounds method may be compared to drawing a

text: polygon

text: .  Metes are points which are like the vertices (corners) of a polygon.  Bounds are

text: line segment

text: s between two adjacent metes.  Bounds are usually straight lines, but can be curved as long as they are clearly defined.

text: Benson's second book, Far Out: A Space-Time Chronicle, was published by Abrams Books in October 2009. A companion volume to Beyond, Far Out covers such deep space phenomena as nebulae, star clusters, galaxies, and galaxy clusters. It also contains a series of short "sidebar" stories that trace various epochs of Earth history and link those periods to the main astronomical subjects of the books. These shorter stories are tied to the astronomical phenomena being depicted according to the light travel time between the Earth and the deep space objects in question. Reviewing the book for The New York Times, Dennis Overbye wrote "Actually 'exquisite' does not really do justice to the aesthetic and literary merits of the book, published in the fall... You can sit and look through this book for hours and never be bored by the shapes, colors and textures into which cosmic creation can arrange itself, or you can actually read the accompanying learned essays. Mr. Benson’s prose is up to its visual surroundings, no mean feat."

text: The constellation also contains the Sculptor Dwarf, a dwarf galaxy which is a member of the Local Group, as well as the Sculptor Group, the group of galaxies closest to the Local Group. The Sculptor Galaxy (NGC 253), a barred spiral galaxy and the largest member of the group, lies near the border between Sculptor and Cetus. Another prominent member of the group is the irregular galaxy NGC 55.

text: The constellation also contains the

text: Sculptor Dwarf

text: , a

text: dwarf galaxy

text: which is a member of the

text: Local Group

text: , as well as the

text: Sculptor Group

text: , the group of galaxies closest to the Local Group. The

text: Sculptor Galaxy

text: (NGC 253), a

text: barred spiral galaxy

text: and the largest member of the group, lies near the border between Sculptor and

text: Cetus

text: . Another prominent member of the group is the

text: irregular galaxy

text: NGC 55

text: Like many other galaxies of similar type, the Milky Way consists of a large mass of stars shaped into the form of a relatively flat disc by gravity. The disc is rotating, with the dense central body of stars moving at greater speeds than those towards the rim of the disc.  As a result, the pattern of stars within the Galaxy as viewed from directly above or below the disc has formed into a spiral.

text: Like many other galaxies of similar type, the Milky Way consists of a large mass of

text: star

text: s shaped into the form of a relatively flat disc by

text: gravity

text: . The disc is rotating, with the dense central body of stars moving at greater speeds than those towards the rim of the disc.  As a result, the pattern of stars within the Galaxy as viewed from directly above or below the disc has formed into a spiral.

text: SDSS J1229+1122 (SDSS J122952.66+112227.8) is a blue supergiant O-type star in the tail of dwarf irregular galaxy IC 3418. It illuminates a nebula clump of gas, and was discovered from the spectrum of the illumination source. The clump of gas resides in a tail caused by ram pressure stripping of gas from the galaxy by the galaxy cluster. It was determined to be a blue supergiant through analysis of its spectrum. As of 2013, it is the most distant known star, at  (stars more distant than this are only known through events that they cause, such as stellar explosions of supernovae and gamma ray bursts). The discovery was made by Drs. Youichi Ohyama and Ananda Hota, using the Subaru Telescope. The star and its galaxy are in the Virgo Cluster of galaxies. The clump of gas that the star illuminates is referred to as D3 or IC3418 D3, and lies within a filamentary structure referred to as F1 or IC3418 F1. The galactic tail and all within it are escaping the galaxy to become intracluster flotsam, unattached to any galaxy, just the cluster.

text: SDSS J1229+1122 (

text: SDSS

text: J

text: 122952.66+112227.8) is a

text: blue supergiant

text: O-type star in the tail of

text: dwarf irregular

text: galaxy

text: IC 3418

text: . It illuminates a

text: nebula

text: clump of gas, and was discovered from the spectrum of the illumination source. The clump of gas resides in a tail caused by ram pressure stripping of gas from the galaxy by the galaxy cluster. It was determined to be a blue supergiant through analysis of its spectrum. As of 2013, it is the most distant known star, at  (stars more distant than this are only known through events that they cause, such as stellar explosions of

text: supernova

text: e and

text: gamma ray burst

text: s). The discovery was made by Drs. Youichi Ohyama and Ananda Hota, using the

text: Subaru Telescope

text: . The star and its galaxy are in the

text: Virgo Cluster

text: of galaxies. The clump of gas that the star illuminates is referred to as D3 or IC3418 D3, and lies within a filamentary structure referred to as F1 or IC3418 F1. The galactic tail and all within it are escaping the galaxy to become intracluster flotsam, unattached to any galaxy, just the cluster.

text: These radio sources are almost universally found hosted by elliptical galaxies, though there is one well-documented exception, namely NGC 4151. Some Seyfert galaxies show weak, small radio jets, but they are not radio-luminous enough to be classified as radio-loud. Such information as there is about the host galaxies of radio-loud quasars and blazars suggests that they are also hosted by elliptical galaxies.

text: These radio sources are almost universally found

text: hosted

text: by

text: elliptical galaxies

text: , though there is one well-documented exception, namely

text: NGC 4151

text: . Some

text: Seyfert galaxies

text: show weak, small radio jets, but they are not radio-luminous enough to be classified as radio-loud. Such information as there is about the host galaxies of radio-loud

text: quasar

text: s and

text: blazar

text: s suggests that they are also hosted by elliptical galaxies.

text: The Bullet Cluster is one of the hottest known clusters of galaxies. It provides an observable constraint for cosmological models, which may diverge at temperatures beyond their predicted critical cluster temperature. Observed from Earth, the subcluster passed through the cluster center 150 million years ago, creating a "bow-shaped shock wave located near the right side of the cluster" formed as "70 million degree Celsius gas in the sub-cluster plowed through 100 million degree Celsius gas in the main cluster at a speed of about 6 million miles per hour". This energy output is equivalent to that of 10 typical quasars.

text: The Bullet Cluster is one of the

text: hottest

text: known

text: clusters of galaxies

text: . It provides an observable constraint for cosmological models, which may diverge at temperatures beyond their predicted critical cluster temperature. Observed from

text: Earth

text: , the subcluster passed through the cluster center 150

text: million years ago

text: , creating a "bow-shaped

text: shock wave

text: located near the right side of the cluster" formed as "70 million degree Celsius gas in the sub-cluster plowed through

text: 100 million degree

text: Celsius gas in the main cluster at a speed of about 6 million miles per hour". This energy output is equivalent to that of 10 typical quasars.

text: Currently, astronomers know little about the shape and size of our galaxy relative to what they know about other galaxies; it is difficult to observe the entire Milky Way from the inside. A good analogy is trying to observe a marching band as a member of the band. Observing other galaxies is much easier because humans are outside those galaxies. Steven Majewski and his team planned to use SIM Lite to help determine not only the shape and size of the Galaxy but also the distribution of its mass and the motion of its stars.

text: Research at the department is made in a number of scientific areas, including exoplanets, stars, star clusters, cosmology, gravitational-wave astronomy, the high-redshift universe, AGN, galaxies and galaxy clusters. This is a mixture of observational astronomy, over the entire electromagnetic spectrum, computational theoretical astronomy, and analytic theoretical research.

text: Research at the department is made in a number of scientific areas, including

text: exoplanets

text: star

text: s, star clusters,

text: cosmology

text: gravitational-wave astronomy

text: , the high-

text: redshift

text: universe,

text: AGN

text: galaxies

text: and

text: galaxy clusters

text: . This is a mixture of observational astronomy, over the entire electromagnetic spectrum, computational theoretical astronomy, and analytic theoretical research.

text: To measure this tangential alignment, it is necessary to measure the ellipticities of the background galaxies and construct a statistical estimate of their systematic alignment.  The fundamental problem is that galaxies are not intrinsically circular, so their measured ellipticity is a combination of their intrinsic ellipticity and the gravitational lensing shear.  Typically, the intrinsic ellipticity is much greater than the shear (by a factor of 3-300, depending on the foreground mass).  The measurements of many background galaxies must be combined to average down this "shape noise". The orientation of intrinsic ellipticities of galaxies should be almost entirely random, so any systematic alignment between multiple galaxies can generally be assumed to be caused by lensing.

text: To measure this tangential alignment, it is necessary to measure the

text: ellipticities

text: of the background galaxies and construct a statistical estimate of their systematic alignment.  The fundamental problem is that galaxies are not intrinsically circular, so their measured ellipticity is a combination of their intrinsic ellipticity and the gravitational lensing shear.  Typically, the intrinsic ellipticity is much greater than the shear (by a factor of 3-300, depending on the foreground mass).  The measurements of many background galaxies must be combined to average down this "shape noise". The orientation of intrinsic ellipticities of galaxies should be almost entirely random, so any systematic alignment between multiple galaxies can generally be assumed to be caused by lensing.

text: NGC 6745 is an irregular spiral galaxy in Lyra that is at a distance of 208 million light-years. Several million years ago, it collided with a smaller galaxy, which created a region filled with young, hot, blue stars. Astronomers do not know if the collision was simply a glancing blow or a prelude to a full-on merger, which would end with the two galaxies incorporated into one larger, probably elliptical galaxy.

text: NGC 6745

text: is an irregular

text: spiral galaxy

text: in Lyra that is at a distance of 208 million light-years. Several million years ago, it

text: collided

text: with a smaller galaxy, which created a region filled with young, hot, blue stars. Astronomers do not know if the collision was simply a glancing blow or a prelude to a full-on merger, which would end with the two galaxies incorporated into one larger, probably

text: elliptical galaxy

text: Although the vast majority of galaxies in the Universe are moving away from the Milky Way, the Andromeda Galaxy, the largest member of the Local Group of galaxies, is heading toward it at about 120 km/s. In 4 billion years, Andromeda and the Milky Way will collide, causing both to deform as tidal forces distort their outer arms into vast tidal tails. If this initial disruption occurs, astronomers calculate a 12% chance that the Solar System will be pulled outward into the Milky Way's tidal tail and a 3% chance that it will become gravitationally bound to Andromeda and thus a part of that galaxy. After a further series of glancing blows, during which the likelihood of the Solar System's ejection rises to 30%, the galaxies' supermassive black holes will merge. Eventually, in roughly 6 billion years, the Milky Way and Andromeda will complete their merger into a giant elliptical galaxy. During the merger, if there is enough gas, the increased gravity will force the gas to the centre of the forming elliptical galaxy. This may lead to a short period of intensive star formation called a starburst. In addition, the infalling gas will feed the newly formed black hole, transforming it into an active galactic nucleus. The force of these interactions will likely push the Solar System into the new galaxy's outer halo, leaving it relatively unscathed by the radiation from these collisions.

text: Although the vast majority of galaxies in the Universe are moving away from the Milky Way, the Andromeda Galaxy, the largest member of the

text: Local Group

text: of galaxies, is heading toward it at about 120 km/s. In 4 billion years, Andromeda and the Milky Way will collide, causing both to deform as

text: tidal force

text: s distort their outer arms into vast

text: tidal tails

text: . If this initial disruption occurs, astronomers calculate a 12% chance that the Solar System will be pulled outward into the Milky Way's tidal tail and a 3% chance that it will become

text: gravitationally

text: bound to Andromeda and thus a part of that galaxy. After a further series of glancing blows, during which the likelihood of the Solar System's ejection rises to 30%, the galaxies'

text: supermassive black hole

text: s will merge. Eventually, in roughly 6 billion years, the Milky Way and Andromeda will complete their merger into a giant

text: elliptical galaxy

text: . During the merger, if there is enough gas, the increased gravity will force the gas to the centre of the forming elliptical galaxy. This may lead to a short period of intensive star formation called a

text: starburst

text: . In addition, the infalling gas will feed the newly formed black hole, transforming it into an

text: active galactic nucleus

text: . The force of these interactions will likely push the Solar System into the new galaxy's outer halo, leaving it relatively unscathed by the radiation from these collisions.

text: The best-known polar-ring galaxies are S0s (lenticular galaxies), but from the physical point of view they are part of a wider category of galaxies, including several ellipticals.

text: The best-known polar-ring galaxies are

text: (lenticular galaxies), but from the physical point of view they are part of a wider category of galaxies, including several

text: ellipticals

text: The spiral arms in these galaxies have an asymmetric appearance. One spiral arm may appear to be considerably brighter than the other. In the photographic plates produced by Arp, the bright arm would look dark or "heavy". While most of these galaxies (such as M101 and NGC 6946) are simply asymmetric spiral galaxies, NGC 6365 is an interacting pair of galaxies where one of the two galaxies is viewed edge-on and just happens to lie where the spiral arm for the other face-on galaxy would be visible.

text: The spiral arms in these galaxies have an asymmetric appearance. One spiral arm may appear to be considerably brighter than the other. In the photographic plates produced by Arp, the bright arm would look dark or "heavy". While most of these galaxies (such as

text: and

text: NGC 6946

text: ) are simply asymmetric spiral galaxies,

text: NGC 6365

text: is an interacting pair of galaxies where one of the two galaxies is viewed edge-on and just happens to lie where the spiral arm for the other face-on galaxy would be visible.

text: Dwingeloo 2 is a small irregular galaxy discovered in 1996 and located about 10 million light-years away from the Earth. Its discovery was a result of Dwingeloo Obscured Galaxy Survey (DOGS) of the Zone of Avoidance. Dwingeloo 2 is a companion galaxy of Dwingeloo 1.

text: Dwingeloo 2 is a small

text: irregular galaxy

text: discovered in 1996 and located about 10 million

text: light-year

text: s away from the Earth. Its discovery was a result of Dwingeloo Obscured Galaxy Survey (DOGS) of the

text: Zone of Avoidance

text: . Dwingeloo 2 is a companion galaxy of

text: Dwingeloo 1

text: Unknown eons later the force bubble crashes on a planet named Caldor in another galaxy, where almost immediately Aknaton goads Vanth into shooting him in a fit of rage and guilt over the obliteration of the Milky Way. Mortally wounded, Aknaton confesses that he goaded Vanth into killing him because he cannot live with the guilt over what he has done. As he dies, he tells Vanth that he saved him and brought him here because this galaxy (later identified as the Empirical Galaxy) is at a point where it might or might not go the way of the Milky Way, developing Zygoteans of its own. Aknaton wants Vanth to change the destiny of this new galaxy, or, failing that, find the Infinity Horn and give this galaxy the same mercy killing given the Milky Way.

text: Unknown eons later the force bubble crashes on a planet named

text: Caldor

text: in another galaxy, where almost immediately Aknaton goads Vanth into shooting him in a fit of rage and guilt over the obliteration of the Milky Way. Mortally wounded, Aknaton confesses that he goaded Vanth into killing him because he cannot live with the guilt over what he has done. As he dies, he tells Vanth that he saved him and brought him here because this galaxy (later identified as the

text: Empirical Galaxy

text: ) is at a point where it might or might not go the way of the Milky Way, developing Zygoteans of its own. Aknaton wants Vanth to change the destiny of this new galaxy, or, failing that, find the Infinity Horn and give this galaxy the same mercy killing given the Milky Way.

text: The area of a shape can be measured by comparing the shape to squares of a fixed size. In the International System of Units (SI), the standard unit of area is the square metre (written as m), which is the area of a square whose sides are one metre long.  A shape with an area of three square metres would have the same area as three such squares.  In mathematics, the unit square is defined to have area one, and the area of any other shape or surface is a dimensionless real number.

text: The area of a shape can be measured by comparing the shape to

text: square

text: s of a fixed size. In the

text: International System of Units

text: (SI), the standard unit of area is the

text: square metre

text: (written as m), which is the area of a square whose sides are one

text: metre

text: long.  A shape with an area of three square metres would have the same area as three such squares.  In

text: mathematics

text: , the

text: unit square

text: is defined to have area one, and the area of any other shape or surface is a

text: dimensionless

text: real number

text: The Triangulum Galaxy, also known as Messier 33, was discovered by Giovanni Battista Hodierna in the 17th century. A distant member of the Local Group, it is about 2.3 million light-years away, and at magnitude 5.8 it is bright enough to be seen by the naked eye under the darkest skies. Under light-polluted skies, it is challenging or invisible even in a small telescope or binoculars. Because of its low surface brightness, low power is required. It is a spiral galaxy with a diameter of 46,000 light-years and is thus smaller than both the Andromeda Galaxy and the Milky Way. A distance of less than 300 kiloparsecs between it and Andromeda supports the hypothesis that it is a satellite of the larger galaxy. Within the constellation, it lies near the border of Pisces, 3.5 degrees west-northwest of Alpha Trianguli and 7 degrees southwest of Beta Andromedae. Within the galaxy, NGC 604 is an H II region where star formation takes place.

text: The

text: Triangulum Galaxy

text: , also known as Messier 33, was discovered by

text: Giovanni Battista Hodierna

text: in the 17th century. A distant member of the

text: Local Group

text: , it is about 2.3 million light-years away, and at magnitude 5.8 it is bright enough to be seen by the naked eye under the darkest skies. Under

text: light-polluted

text: skies, it is challenging or invisible even in a small telescope or binoculars. Because of its low surface brightness, low power is required. It is a

text: spiral galaxy

text: with a diameter of 46,000 light-years and is thus smaller than both the

text: Andromeda Galaxy

text: and the

text: Milky Way

text: . A distance of less than 300

text: kiloparsecs

text: between it and Andromeda supports the hypothesis that it is a satellite of the larger galaxy. Within the constellation, it lies near the border of Pisces, 3.5 degrees west-northwest of Alpha Trianguli and 7 degrees southwest of

text: Beta Andromedae

text: . Within the galaxy,

text: NGC 604

text: is an

text: H II region

text: where star formation takes place.

text: A globular cluster is a spherical collection of stars that orbits a galactic core  as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is derived from the Latin globulus—a small sphere. A globular cluster is sometimes known more simply as a globular.

text: A globular cluster is a

text: spherical

text: collection of

text: star

text: s that orbits a

text: galactic core

text: as a

text: satellite

text: . Globular clusters are very tightly bound by

text: gravity

text: , which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of

text: star cluster

text: is derived from the

text: Latin

text: globulus—a small sphere. A globular cluster is sometimes known more simply as a globular.

text: Most identified dwarf spiral galaxies are located outside clusters. Strong gravitational interactions between galaxies and interactions between galaxies and intracluster gas are expected to destroy the disks of most dwarf spiral galaxies.   Nonetheless, dwarf galaxies with spiral-like structure have been identified within the Virgo Cluster and Coma Cluster.

text: Most identified dwarf spiral galaxies are located outside

text: clusters

text: . Strong gravitational interactions between galaxies and interactions between galaxies and

text: intracluster gas

text: are expected to destroy the disks of most dwarf spiral galaxies.   Nonetheless, dwarf galaxies with spiral-like structure have been identified within the

text: Virgo Cluster

text: and

text: Coma Cluster

text: 1936 Elliptical galaxies

text: Elliptical galaxies

text: Post-graduation, Shapley received a fellowship to Princeton University for graduate work, where he studied under Henry Norris Russell and used the period-luminosity relation for Cepheid variable stars (discovered by Henrietta Swan Leavitt) to determine distances to globular clusters. He was instrumental in moving astronomy away from the idea that Cepheids were spectroscopic binaries, and toward the concept that they were pulsators. He was the first to realize that the Milky Way Galaxy was much larger than previously believed, and that the Sun's place in the galaxy was in a nondescript location. This discovery by Shapley is a part of the Copernican principle, according to which the Earth is not at the center of our Solar System, our galaxy, or our Universe.

text: Post-graduation, Shapley received a fellowship to

text: Princeton University

text: for graduate work, where he studied under

text: Henry Norris Russell

text: and used the period-luminosity relation for

text: Cepheid variable star

text: s (discovered by

text: Henrietta Swan Leavitt

text: ) to determine distances to

text: globular cluster

text: s. He was instrumental in moving astronomy away from the idea that Cepheids were spectroscopic binaries, and toward the concept that they were pulsators. He was the first to realize that the

text: Milky Way Galaxy

text: was much larger than previously believed, and that the Sun's place in the galaxy was in a nondescript location. This discovery by Shapley is a part of the

text: Copernican principle

text: , according to which the Earth is not at the center of our Solar System, our galaxy, or our Universe.

text: The weight attached to each end of the chain could have many different sizes and shapes. The weights were usually exactly matched in size and shape. On some of the related chain and weight weapons the weights could be completely different from each other, with one weight being much longer than the other like a handle on one end, or one weight could be round while the other weight could be rectangular. Weight shapes include round, hexagonal, or rectangular.  The weight could be fairly light or quite heavy with the typical weight being from 2 ounces (56 grams) to 4 ounces (112 grams).

text: The Coma Supercluster contains the Coma and Leo Cluster of galaxies. The Coma Cluster, which forms Berenice's imaginary tresses, is 230 to 300 million light-years away. It is one of the largest known clusters, with at least 10,000 galaxies (mainly elliptical, with a few spiral galaxies). Due to its distance from Earth, most of the galaxies are visible only through large telescopes. Its brightest members are NGC 4889 and NGC 4874, both with a magnitude of 13; most others are magnitude 15 or dimmer. NGC 4889 is a giant elliptical galaxy with one of the largest known black holes (21 billion solar masses), and NGC 4921 is the cluster's brightest spiral galaxy. After observing the Coma Cluster, astronomer Fritz Zwicky first postulated the existence of dark matter during the 1930s. The massive galaxy Dragonfly 44 discovered in 2015 was found to consist almost entirely of dark matter. Its mass is very similar to that of the Milky Way.

text: The

text: Coma Supercluster

text: contains the

text: Coma

text: and

text: Leo Cluster

text: of galaxies. The Coma Cluster, which forms Berenice's imaginary tresses, is 230 to 300 million light-years away. It is one of the largest known clusters, with at least 10,000 galaxies (mainly

text: elliptical

text: , with a few

text: spiral galaxies

text: ). Due to its distance from Earth, most of the galaxies are visible only through large telescopes. Its brightest members are

text: NGC 4889

text: and

text: NGC 4874

text: , both with a magnitude of 13; most others are magnitude 15 or dimmer. NGC 4889 is a giant elliptical galaxy with one of the largest known

text: black hole

text: s (21 billion

text: solar mass

text: es), and

text: NGC 4921

text: is the cluster's brightest spiral galaxy. After observing the Coma Cluster, astronomer

text: Fritz Zwicky

text: first postulated the existence of

text: dark matter

text: during the 1930s. The massive galaxy

text: Dragonfly 44

text: discovered in 2015 was found to consist almost entirely of dark matter. Its mass is very similar to that of the

text: Milky Way

text: Secondary crater size is dictated by the size of its parent primary crater. Primary craters can vary from microscopic to thousands of kilometers wide. The morphology of primary craters ranges from bowl-shaped to large, wide basins, where multi-ringed structures are observed. Two factors dominate the morphologies of these craters: material strength and gravity. The bowl-shaped morphology suggests that the topography is supported by the strength of the material, while the topography of the basin-shaped craters is overcome by gravitational forces and collapses toward flatness. The morphology, and size, of secondary craters is limited. Secondary craters exhibit a maximum diameter of < 5% of its parent primary crater. The size of a secondary crater is also dependent on its distance from its primary. The morphology of secondaries is simple but distinctive. Secondaries that form closer to their primaries appear more elliptical with shallower depths. These may form rays or crater chains. The more distant secondaries appear similar in circularity to their parent primaries, but these are often seen in an array of clusters.

text: The most common result of the gravitational merger between two or more galaxies is an irregular galaxy, but elliptical galaxies may also result.

text: The most common result of the gravitational merger between two or more galaxies is an irregular galaxy, but

text: elliptical galaxies

text: may also result.

text: The galaxy is a result of a collision of two galaxies. This collision is an opportunity for astronomers to study such mergers and to predict the future of our Milky Way after its expected collision with the Andromeda galaxy.

text: The galaxy is a result of a collision of two galaxies. This collision is an opportunity for astronomers to study such mergers and to predict the future of our

text: Milky Way

text: after its expected collision with the

text: Andromeda galaxy

text: The Planetarium uses the Zeiss Model M1015 star projector, manufactured by Carl Zeiss, Inc. of Germany. It is the first of its kind to be installed anywhere in the world. It projects 7,600 stars down to magnitude 6, 25 star clusters and nebulae, the sun, moon, and the five planets visible to the human eye. The Zeiss can show the daily motions of the sky, the sun, the moon, and the positions of the stars on almost any given day, as well as various astronomical grids and scales. Auxiliary equipment allows projection of rainbows, clouds, solar and lunar eclipses, rotating galaxies, double star systems, and varied constellations.

text: The Planetarium uses the

text: Zeiss

text: Model M1015

text: star projector

text: , manufactured by

text: Carl Zeiss

text: , Inc. of

text: Germany

text: . It is the first of its kind to be installed anywhere in the world. It projects 7,600 stars down to

text: magnitude

text: 6, 25

text: star cluster

text: s and

text: nebulae

text: , the

text: sun

text: moon

text: , and the five planets visible to the human eye. The Zeiss can show the daily motions of the sky, the sun, the moon, and the positions of the stars on almost any given day, as well as various astronomical grids and scales. Auxiliary equipment allows projection of rainbows, clouds, solar and lunar eclipses, rotating galaxies, double star systems, and varied constellations.

text: There are about 50 small galaxies confirmed to be within  of the Milky Way, but not all of them are necessarily in orbit, and some may themselves be in orbit of other satellite galaxies. The only ones visible to the naked eye are the Large and Small Magellanic Clouds, which have been observed since prehistory. Measurements with the Hubble Space Telescope in 2006 suggest the Magellanic Clouds may be moving too fast to be orbiting the Milky Way. Of the galaxies confirmed to be in orbit, the largest is the Sagittarius Dwarf Elliptical Galaxy, which has a diameter of  or roughly a fifth that of the Milky Way.

text: There are about 50 small galaxies confirmed to be within  of the Milky Way, but not all of them are necessarily in orbit, and some may themselves be in orbit of other satellite galaxies. The only ones visible to the naked eye are the

text: Large

text: and

text: Small

text: Magellanic Clouds, which have been observed since prehistory. Measurements with the Hubble Space Telescope in 2006 suggest the Magellanic Clouds may be moving too fast to be orbiting the

text: Milky Way

text: . Of the galaxies confirmed to be in orbit, the largest is the

text: Sagittarius Dwarf Elliptical Galaxy

text: , which has a diameter of  or roughly a fifth that of the Milky Way.

text: The Coma Supercluster (SCl 117) is a nearby supercluster of galaxies comprising the Coma Cluster (Abell 1656) and the Leo Cluster (Abell 1367). Located 300 million light-years from Earth, it is in the center of the Great Wall. The Coma Supercluster is the nearest massive cluster of galaxies to our own Virgo Supercluster. It is roughly spherical, about 20 million light-years in diameter and contains more than 3,000 galaxies. It is located in the constellation Coma Berenices.  Being one of the first superclusters to be discovered, the Coma Supercluster helped astronomers understand the large scale structure of the universe.

text: The Coma Supercluster (SCl 117) is a nearby

text: supercluster

text: of

text: galaxies

text: comprising the

text: Coma Cluster

text: (Abell 1656) and the

text: Leo Cluster

text: (Abell 1367). Located 300 million

text: light-year

text: s from

text: Earth

text: , it is in the center of the

text: Great Wall

text: . The Coma Supercluster is the nearest massive cluster of galaxies to our own

text: Virgo Supercluster

text: . It is roughly spherical, about 20 million light-years in diameter and contains more than 3,000 galaxies. It is located in the constellation

text: Coma Berenices

text: .  Being one of the first superclusters to be discovered, the Coma Supercluster helped

text: astronomer

text: s understand the

text: large scale structure of the universe

text: The Ford Galaxie is a full-size car that was built in the United States by Ford for model years 1959 through 1974. The name was used for the top models in Ford's full-size range from 1958 until 1961, in a marketing attempt to appeal to the excitement surrounding the Space Race. For 1962, all full-size Fords wore the Galaxie badge, with "500" and "500/XL" denoting the higher series. The Galaxie 500/LTD was introduced for 1965 followed by the Galaxie 500 7-Litre for 1966. The Galaxie 500 part was dropped from the LTD in 1966, and from the XL in 1967; however the basic series structuring levels were maintained. The "regular" Galaxie 500 continued below the LTD as Ford's mid-level full-size model from 1965 until its demise at the end of the 1974 model year.

text: The Ford Galaxie is a

text: full-size car

text: that was built in the United States by

text: Ford

text: for model years 1959 through 1974. The name was used for the top models in Ford's full-size range from 1958 until 1961, in a marketing attempt to appeal to the excitement surrounding the

text: Space Race

text: . For 1962, all full-size Fords wore the Galaxie badge, with "500" and "500/XL" denoting the higher series. The Galaxie 500/LTD was introduced for 1965 followed by the Galaxie 500 7-Litre for 1966. The Galaxie 500 part was dropped from the LTD in 1966, and from the XL in 1967; however the basic series structuring levels were maintained. The "regular" Galaxie 500 continued below the

text: LTD

text: as Ford's mid-level full-size model from 1965 until its demise at the end of the 1974 model year.

text: In 4161, Irravel stops at the Pleiades cluster and meets distant descendants of the Conjoiners living amongst a race known as the Islanders, who inhabit the planets in the star cluster. Markarian is still fleeing her. She learns that the Greenflies are now consuming whole star systems at a massive rate, surging outward in a fractal pattern in massive swarming tendril-like waves made of substantial fractions of the mass orbiting each star. She also discovers that herself, Markarian, Mirsky, and Seven, their confrontation having unleashed the Greenfly upon the galaxy, have receded into the mists of prehistory and become mythologised as primordial figures. The Islanders put on a play, in which Irravel (unknown to the Islanders) plays herself in a  highly ritualised performance, where it is customary for a human bearing the by-then common ancestral name Irravel to play the character. During the feast later that evening, she tries to tell them that she truly is the same person depicted in the Islanders' play, but they disbelieve her, as many Irravels make such insistences with no particular claim to legitimacy. She leaves the next morning, still in pursuit of Markarian.

text: In 4161, Irravel stops at the

text: Pleiades

text: The Leo Triplet (also known as the M66 Group) is a small group of galaxies about 35 million light-years away in the constellation Leo.  This galaxy group consists of the spiral galaxies M65, M66, and NGC 3628.

text: The Leo Triplet (also known as the M66 Group) is a small

text: group of galaxies

text: about

text: 35 million

text: light-year

text: s away in the

text: constellation

text: Leo

text: .  This galaxy group consists of the

text: spiral galaxies

text: , and

text: NGC 3628

text: The Carina Dwarf Spheroidal Galaxy is a dwarf galaxy in the Carina constellation.  It was discovered in 1977 with the UK Schmidt Telescope by Cannon et al. The Carina Dwarf Spheroidal galaxy is a satellite galaxy of the Milky Way and is receding from it at 230 km/s. The diameter of the galaxy is about 1600 light-years, which is 75 times smaller than the Milky Way. Most of the stars in the galaxy formed 7 billion years ago, although it also experienced bursts of star formation about 13 and 3 billion years ago. It is also being tidally disrupted by the Milky Way galaxy.

text: The Carina Dwarf Spheroidal Galaxy is a

text: dwarf galaxy

text: in the

text: Carina

text: constellation

text: .  It was discovered in 1977 with the

text: UK Schmidt Telescope

text: by Cannon et al. The Carina Dwarf Spheroidal galaxy is a

text: satellite galaxy

text: of the Milky Way and is receding from it at 230 km/s. The diameter of the galaxy is about 1600 light-years, which is 75 times smaller than the Milky Way. Most of the stars in the galaxy formed 7 billion years ago, although it also experienced bursts of star formation about 13 and 3 billion years ago. It is also being

text: tidally

text: disrupted by the Milky Way galaxy.

text: A dwarf spiral galaxy is the dwarf version of a spiral galaxy.  Dwarf galaxies are characterized as having low luminosities, small diameters (less than 5 kpc), low surface brightnesses, and low hydrogen masses. The galaxies may be considered a subclass of low-surface-brightness galaxies.

text: A dwarf spiral galaxy is the dwarf version of a

text: spiral galaxy

text: .  Dwarf galaxies are characterized as having low

text: luminosities

text: , small diameters (less than 5

text: kpc

text: ), low surface brightnesses, and low

text: hydrogen

text: masses. The galaxies may be considered a subclass of

text: low-surface-brightness galaxies

text: These are objects that appear to be a series of irregular clumps with no coherent structure. Many of these objects are simply nearby dwarf galaxies. Some of these objects are interacting galaxies, while others are small groups of galaxies. In both cases, many of the constituent galaxies are irregular galaxies. The superposition of two or more such irregular galaxies can easily look like a single larger irregular galaxy, which is why the Atlas of Peculiar Galaxies (and other catalogs) often classify these pairs and groups as single objects.

text: These are objects that appear to be a series of irregular clumps with no coherent structure. Many of these objects are simply nearby

text: dwarf galaxies

text: . Some of these objects are interacting galaxies, while others are small

text: groups of galaxies

text: . In both cases, many of the constituent galaxies are irregular galaxies. The superposition of two or more such irregular galaxies can easily look like a single larger irregular galaxy, which is why the Atlas of Peculiar Galaxies (and other catalogs) often classify these pairs and groups as single objects.

text: A quasar () is a compact region surrounding a supermassive black hole and emitting enormous amounts of electromagnetic energy as mass from the core of a surrounding galaxy, under the influence of the black hole's gravity, falls onto its accretion disk. Although ranging in size from only 10 to 10,000 times the Schwarzschild radius of the enclosed black hole, quasars are the most energetic form of active galactic nucleus (AGN), emitting radio waves and visible light up to 100 times the luminosity of the entire Milky Way Galaxy.

text: A quasar () is a compact region surrounding a

text: supermassive black hole

text: and emitting enormous amounts of

text: electromagnetic energy

text: as mass from the core of a surrounding galaxy, under the influence of the black hole's

text: gravity

text: , falls onto its

text: accretion disk

text: . Although ranging in size from only 10 to 10,000 times the

text: Schwarzschild radius

text: of the enclosed

text: black hole

text: , quasars are the most energetic form of

text: active galactic nucleus

text: (AGN), emitting

text: radio waves

text: and

text: visible light

text: up to 100 times the luminosity of the entire

text: Milky Way Galaxy

text: Curtis on the other side contended that Andromeda and other such "nebulae" were separate galaxies, or "island universes" (a term invented by the 18th-century philosopher Immanuel Kant, who also believed that the "spiral nebulae" were extragalactic). He showed that there were more novae in Andromeda than in the Milky Way. From this he could ask why there were more novae in one small section of the galaxy than the other sections of the galaxy, if Andromeda was not a separate galaxy but simply a nebula within the Earth's galaxy. This led to supporting Andromeda as a separate galaxy with its own signature age and rate of nova occurrences. He also cited dark lanes present in other galaxies similar to the dust clouds found in the Earth's own galaxy and massive doppler shifts found in other galaxies.

text: Curtis on the other side contended that Andromeda and other such "nebulae" were separate galaxies, or "

text: island universe

text: s" (a term invented by the 18th-century philosopher

text: Immanuel Kant

text: , who also believed that the "spiral nebulae" were extragalactic). He showed that there were more

text: nova

text: e in Andromeda than in the Milky Way. From this he could ask why there were more novae in one small section of the galaxy than the other sections of the galaxy, if Andromeda was not a separate galaxy but simply a nebula within the Earth's galaxy. This led to supporting Andromeda as a separate galaxy with its own signature age and rate of

text: nova

text: occurrences. He also cited dark lanes present in other galaxies similar to the dust clouds found in the Earth's own galaxy and massive

text: doppler shift

text: s found in other galaxies.

text: The telepaths however were nothing but martyrs taking part in a plot set by the Second Foundation to mislead the people of Terminus into thinking that the threat of the Second Foundation no longer exists, thus having the original Seldon Plan restored while its location remains secret. The Second Foundation is actually located on Trantor—the former capital of the Galactic Empire—in the center of the galaxy. It was called "Star's End" due to the ancient saying that "All roads lead to Trantor, and that is where all stars end". The location was also said to fit the "other end of the galaxy" location since the galaxy is not in fact a disc, but a spiral—and from the edge, the other end of a spiral lies at the center. The book also noted that Hari Seldon was a social scientist, not a physical one. When the two Foundations were founded, they could be described as being at opposite social ends of the Galaxy, with Trantor at the very center of galactic power and prestige, and Terminus at the other extreme, something the First Foundation failed to realize because its members were inclined to analyze Seldon's statement in physical terms.

text: The telepaths however were nothing but martyrs taking part in a plot set by the Second Foundation to mislead the people of Terminus into thinking that the threat of the Second Foundation no longer exists, thus having the original Seldon Plan restored while its location remains secret. The Second Foundation is actually located on

text: Trantor

text: —the former capital of the Galactic Empire—in the center of the galaxy. It was called "Star's End" due to the ancient saying that "All roads lead to Trantor, and that is where all stars end". The location was also said to fit the "other end of the galaxy" location since the galaxy is not in fact a disc, but a spiral—and from the edge, the other end of a spiral lies at the center. The book also noted that

text: Hari Seldon

text: was a

text: social

text: scientist, not a

text: physical

text: one. When the two Foundations were founded, they could be described as being at opposite social ends of the Galaxy, with Trantor at the very center of galactic power and prestige, and Terminus at the other extreme, something the First Foundation failed to realize because its members were inclined to analyze Seldon's statement in physical terms.

text: The Andromeda Galaxy is currently approximately 2.5 million light years away from our galaxy, the Milky Way Galaxy, and they are moving towards each other at approximately 300 kilometers (186 miles) per second. Approximately five billion years from now, or 19 billion years after the Big Bang, the Milky Way and the Andromeda Galaxy will collide with one another and merge into one large galaxy based on current evidence. Up until 2012, there was no way to know whether the possible collision was definitely going to happen or not. In 2012, researchers came to the conclusion that the collision is definite after using the Hubble Space Telescope between 2002 and 2010 to track the motion of Andromeda.

text: The

text: Andromeda Galaxy

text: is currently approximately 2.5 million light years away from our galaxy, the

text: Milky Way Galaxy

text: , and they are moving towards each other at approximately 300 kilometers (186 miles) per second. Approximately five billion years from now, or 19 billion years after the Big Bang, the Milky Way and the Andromeda Galaxy will collide with one another and merge into one large galaxy based on current evidence. Up until 2012, there was no way to know whether the possible collision was definitely going to happen or not. In 2012, researchers came to the conclusion that the collision is definite after using the Hubble Space Telescope between 2002 and 2010 to track the motion of Andromeda.

text: In 2005, astronomers discovered a completely new type of star cluster in the Andromeda Galaxy, which is, in several ways, very similar to globular clusters (although less dense). Currently, there are not any intermediate clusters (also known as extended globular clusters) discovered in the Milky Way. The three discovered in Andromeda Galaxy are M31WFS C1 M31WFS C2, and M31WFS C3.

text: In 2005, astronomers discovered a completely new type of star cluster in the Andromeda Galaxy, which is, in several ways, very similar to globular clusters (although less dense). Currently, there are not any intermediate clusters (also known as extended globular clusters) discovered in the Milky Way. The three discovered in

text: Andromeda Galaxy

text: are

text: M31WFS C1

text: M31WFS C2

text: , and

text: M31WFS C3

text: In 2005, astronomers discovered a completely new type of star cluster in the Andromeda Galaxy. The new-found clusters contain hundreds of thousands of stars, a similar number of stars that can be found in globular clusters. What distinguishes them from the globular clusters is that they are much larger—several hundred light-years across—and hundreds of times less dense. The distances between the stars are, therefore, much greater within the newly discovered extended clusters.

text: Unlike those of most sports, baseball playing fields can vary significantly in size and shape. While the dimensions of the infield are specifically regulated, the only constraint on outfield size and shape for professional teams following the rules of Major League and Minor League Baseball is that fields built or remodeled since June 1, 1958, must have a minimum distance of  from home plate to the fences in left and right field and  to center. Major league teams often skirt even this rule. For example, at Minute Maid Park, which became the home of the Houston Astros in 2000, the Crawford Boxes in left field are only  from home plate. There are no rules at all that address the height of fences or other structures at the edge of the outfield. The most famously idiosyncratic outfield boundary is the left-field wall at Boston's Fenway Park, in use since 1912: the Green Monster is  from home plate down the line and  tall.

text: Unlike those of most sports, baseball playing fields can vary significantly in size and shape. While the dimensions of the infield are specifically regulated, the only constraint on outfield size and shape for professional teams following the rules of Major League and Minor League Baseball is that fields built or remodeled since June 1, 1958, must have a minimum distance of  from home plate to the fences in left and right field and  to center. Major league teams often skirt even this rule. For example, at

text: Minute Maid Park

text: , which became the home of the

text: Houston Astros

text: in 2000, the

text: Crawford Boxes

text: in left field are only  from home plate. There are no rules at all that address the height of fences or other structures at the edge of the outfield. The most famously idiosyncratic outfield boundary is the left-field wall at Boston's

text: Fenway Park

text: , in use since 1912: the

text: Green Monster

text: is  from home plate down the line and  tall.

text: Centaurus is rich in galaxies as well. NGC 4622 is a face-on spiral galaxy located 200 million light-years from Earth (redshift 0.0146). Its spiral arms wind in both directions, which makes it nearly impossible for astronomers to determine the rotation of the galaxy. Astronomers theorize that a collision with a smaller companion galaxy near the core of the main galaxy could have led to the unusual spiral structure. NGC 5253, a peculiar irregular galaxy, is located near the border with Hydra and M83, with which it likely had a close gravitational interaction 1-2 billion years ago. This may have sparked the galaxy's high rate of star formation, which continues today and contributes to its high surface brightness. NGC 5253 includes a large nebula and at least 12 large star clusters. In the eyepiece, it is a small galaxy of magnitude 10 with dimensions of 5 arcminutes by 2 arcminutes and a bright nucleus. NGC 4945 is a spiral galaxy seen edge-on from Earth, 13 million light-years away. It is visible with any amateur telescope, as well as binoculars under good conditions; it has been described as "shaped like a candle flame", being long and thin (16' by 3'). In the eyepiece of a large telescope, its southeastern dust lane becomes visible. Another galaxy is NGC 5102, found by star-hopping from Iota Centauri. In the eyepiece, it appears as an elliptical object 9 arcminutes by 2.5 arcminutes tilted on a southwest-northeast axis.

text: Centaurus is rich in galaxies as well.

text: NGC 4622

text: is a face-on

text: spiral galaxy

text: located 200 million light-years from Earth (redshift 0.0146). Its

text: spiral arms

text: wind in both directions, which makes it nearly impossible for astronomers to determine the rotation of the galaxy. Astronomers theorize that a

text: collision

text: with a smaller companion galaxy near the core of the main galaxy could have led to the unusual spiral structure.

text: NGC 5253

text: , a peculiar

text: irregular galaxy

text: , is located near the border with Hydra and

text: , with which it likely had a close gravitational interaction 1-2 billion years ago. This may have sparked the galaxy's high rate of star formation, which continues today and contributes to its high surface brightness. NGC 5253 includes a large nebula and at least 12 large star clusters. In the eyepiece, it is a small galaxy of magnitude 10 with dimensions of 5 arcminutes by 2 arcminutes and a bright nucleus. NGC 4945 is a spiral galaxy seen edge-on from Earth, 13 million light-years away. It is visible with any amateur telescope, as well as

text: binoculars

text: under good conditions; it has been described as "shaped like a candle flame", being long and thin (16' by 3'). In the eyepiece of a large telescope, its southeastern dust lane becomes visible. Another galaxy is

text: NGC 5102

text: , found by star-hopping from

text: Iota Centauri

text: . In the eyepiece, it appears as an elliptical object 9 arcminutes by 2.5 arcminutes tilted on a southwest-northeast axis.

text: In the Local Group, the Milky Way and M31 (the Andromeda Galaxy) are gravitationally bound, and currently approaching each other at high speed. Simulations show that the Milky Way and M31 are on a collision course and are expected to collide in less than five billion years. During this collision, it is expected that the Sun and the rest of the Solar System will be ejected from its current path around the Milky Way. After the collision takes place, the merging of these two galaxies would cause a giant elliptical galaxy to form.

text: In the

text: Local Group

text: , the Milky Way and M31 (the

text: Andromeda Galaxy

text: ) are gravitationally bound, and currently approaching each other at high speed. Simulations show that the Milky Way and M31 are on a collision course and are expected to collide in less than five billion years. During this collision, it is expected that the Sun and the rest of the Solar System will be ejected from its current path around the Milky Way. After the collision takes place, the merging of these two galaxies would cause a giant elliptical galaxy to form.

text: The BOSS Great Wall is a galaxy wall, a subtype of galaxy filaments, that was discovered early 2016. It is one of the largest superstructures in the observable universe. It contains perhaps 10 000 times the mass of the Milky Way. It is 1 billion light years across, and contains 830 visible galaxies, as well as many others that are invisible (dark galaxies). It contains five times the density compared to the standard cosmological density of the universe. Its redshift is about z=0.47 (z times Hubble length ≈ 6800 million light years). Although this structure may look grand in size to us, we may not be able to call it one solid structure just yet. This part of the sky has five times as many galaxies as an average space in the sky, but we know the universe is still expanding. This brings about the question of whether they are all moving together or are slowly separating as the universe expands.

text: The BOSS Great Wall is a

text: galaxy wall

text: , a subtype of

text: galaxy filaments

text: , that was discovered early 2016. It is one of the largest superstructures in the

text: observable universe

text: . It contains perhaps 10 000 times the mass of the

text: Milky Way

text: . It is 1 billion light years across, and contains 830 visible galaxies, as well as many others that are invisible (

text: dark galaxies

text: ). It contains five times the density compared to the standard cosmological density of the universe. Its

text: redshift

text: is about z=0.47 (z times

text: Hubble length

text: ≈ 6800 million light years). Although this structure may look grand in size to us, we may not be able to call it one solid structure just yet. This part of the sky has five times as many galaxies as an average space in the sky, but we know the universe is still expanding. This brings about the question of whether they are all moving together or are slowly separating as the universe expands.

text: UGCA 86 is an irregular galaxy within the IC 342/Maffei Group.

text: UGCA 86 is an

text: irregular galaxy

text: within the

text: IC 342/Maffei Group

text: NGC 4555 is important because of its isolation. Most elliptical galaxies are found in the cores of groups and clusters of galaxies, and almost all those for which dark matter estimates are available are located in the centres of these larger systems. In these circumstances it impossible to know whether the dark matter is associated with the galaxy or the surrounding cluster. NGC 4555, as a field galaxy is not part of any group or cluster, and therefore provides strong evidence that dark matter can be associated with individual ellipticals.

text: NGC 4555 is important because of its isolation. Most elliptical galaxies are found in the cores of

text: groups and clusters of galaxies

text: , and almost all those for which dark matter estimates are available are located in the centres of these larger systems. In these circumstances it impossible to know whether the dark matter is associated with the galaxy or the surrounding cluster. NGC 4555, as a

text: field galaxy

text: is not part of any group or cluster, and therefore provides strong evidence that dark matter can be associated with individual ellipticals.

text: The Samsung Galaxy S II is a touchscreen-enabled, slate-format Android smartphone with the Galaxy S product line.

text: The

text: Samsung Galaxy S II

text: is a

text: touchscreen

text: -enabled,

text: slate

text: -format

text: Android

text: smartphone

text: with the

text: Galaxy S

text: product line.

text: It is possible to differentiate the cannibalism model from the merging model by considering the formation period of the BCGs. In the cannibalism model, there are numerous small galaxies present in the evolved cluster, whereas in the merging model, a hierarchical cosmological model is expected due to the collapse of clusters. It has been shown that the orbit decay of cluster galaxies is not effective enough to account for the growth of BCGs. The merging model is now generally accepted as the most likely one, but recent observations are at odds with some of its predictions. For example, it has been found that the stellar mass of BCG's was assembled much earlier than the merging model predicts.

text: As stated above, the star formation in Messier 90 appears truncated.  Consequently, the galaxy's spiral arms appear to be smooth and featureless, rather than knotted like galaxies with extended star formation., which justifies why this galaxy, along with NGC 4921 in the Coma Cluster has been classified as the prototype of an anemic galaxy. Some authors go even further and consider it is a passive spiral galaxy, similar to those found on galaxy clusters with high redshift.

text: As stated above, the

text: star formation

text: in Messier 90 appears truncated.  Consequently, the galaxy's spiral arms appear to be smooth and featureless, rather than knotted like galaxies with extended star formation., which justifies why this galaxy, along with

text: NGC 4921

text: in the

text: Coma Cluster

text: has been classified as the prototype of an

text: anemic galaxy

text: . Some authors go even further and consider it is a

text: passive spiral galaxy

text: , similar to those found on galaxy clusters with high

text: redshift

text: On the left (in the sense that the sequence is usually drawn) lie the ellipticals. Elliptical galaxies have smooth, featureless light distributions and appear as ellipses in photographic images. They are denoted by the letter E, followed by an integer n representing their degree of ellipticity in the sky. By convention, n is ten times the ellipticity of the galaxy, rounded to the nearest integer, where the ellipticity is defined as  1 − }} for an ellipse with semimajor and semiminor axes of lengths a and b respectively. The ellipticity increases from left to right on the Hubble diagram, with near-circular (E0) galaxies situated on the very left of the diagram. It is important to note that the ellipticity of a galaxy on the sky is only indirectly related to the true 3-dimensional shape (for example, a flattened, discus-shaped galaxy can appear almost round if viewed face-on or elliptical if viewed at an angle). Observationally, the most flattened elliptical galaxies have ellipticities e = 0.7 (denoted E7). This is consistent with their being truly ellipsoidal structures rather than disks viewed at a range of angles.

text: On the left (in the sense that the sequence is usually drawn) lie the

text: ellipticals

text: . Elliptical galaxies have smooth, featureless light distributions and appear as ellipses in photographic images. They are denoted by the letter E, followed by an integer n representing their degree of ellipticity in the sky. By convention, n is ten times the

text: ellipticity

text: of the galaxy, rounded to the nearest integer, where the ellipticity is defined as  1 − }} for an ellipse with semimajor and semiminor axes of lengths a and b respectively. The ellipticity increases from left to right on the Hubble diagram, with near-circular (E0) galaxies situated on the very left of the diagram. It is important to note that the ellipticity of a galaxy on the sky is only indirectly related to the true 3-dimensional shape (for example, a flattened, discus-shaped galaxy can appear almost round if viewed face-on or elliptical if viewed at an angle). Observationally, the most flattened elliptical galaxies have ellipticities e = 0.7 (denoted E7). This is consistent with their being truly

text: ellipsoid

text: al structures rather than disks viewed at a range of angles.

text: Approximately 200 billion () or, more recently, at least 2 trillion galaxies exist in the observable universe. Most of the galaxies are 1,000 to 100,000 parsecs in diameter and usually separated by distances on the order of millions of parsecs (or megaparsecs). The space between galaxies is filled with a tenuous gas having an average density of less than one atom per cubic meter. The majority of galaxies are gravitationally organized into associations known as galaxy groups, clusters, and superclusters. At the largest scale, these associations are generally arranged into sheets and filaments surrounded by immense voids.  The largest structure of galaxies yet recognised is a cluster of superclusters, that has been named Laniakea

text: Approximately 200 billion () or, more recently, at least 2 trillion galaxies exist in the

text: observable universe

text: . Most of the galaxies are 1,000 to 100,000

text: parsec

text: s in diameter and usually separated by distances on the order of millions of parsecs (or megaparsecs). The

text: space

text: between galaxies is filled with a tenuous gas having an average density of less than one

text: atom

text: per cubic meter. The majority of galaxies are gravitationally organized into associations known as

text: galaxy group

text: s,

text: clusters

text: , and

text: superclusters

text: . At the

text: largest scale

text: , these associations are generally arranged into

text: sheets and filaments

text: surrounded by immense

text: voids

text: .  The largest structure of galaxies yet recognised is a cluster of superclusters, that has been named

text: Laniakea

text: The comet galaxy is currently being ripped to pieces. Moving through a cluster at speeds of greater than 2 million mph, is one of the main reasons the gas and stars of the galaxy are being stripped away by the tidal forces of the cluster. Other factors adding to the damage of the galaxy are the cluster's scorching gas plasma. As the galaxy speeds through, its gas and stars are still being stripped away by the tidal forces exerted by the cluster - just as the tidal forces exerted by the moon and Sun push and pull the Earth's oceans. Also contributing to this destructive process is the pressure of the cluster's hot gas plasma reaching temperatures as high as 10-100 million degrees. Scientists estimate that the total duration of the transformation process is close to one billion years. What is seen now in the Hubble's image is roughly 200 million years into the process. Even though the Comet Galaxy’s mass is slightly greater than the Milky Way, it will lose all its gas and dust, and so not be able to generate stars later in life. It will become a gas-poor galaxy with an old population of red stars.

text: The comet galaxy is currently being ripped to pieces. Moving through a cluster at speeds of greater than 2 million mph, is one of the main reasons the gas and stars of the galaxy are being stripped away by the

text: tidal forces

text: of the cluster. Other factors adding to the damage of the galaxy are the cluster's scorching

text: gas plasma

text: . As the galaxy speeds through, its gas and stars are still being stripped away by the tidal forces exerted by the cluster - just as the tidal forces exerted by the

text: moon

text: and

text: Sun

text: push and pull the Earth's

text: ocean

text: s. Also contributing to this destructive process is the pressure of the cluster's hot gas plasma reaching temperatures as high as 10-100 million degrees. Scientists estimate that the total duration of the transformation process is close to one billion years. What is seen now in the Hubble's image is roughly 200 million years into the process. Even though the Comet Galaxy’s mass is slightly greater than the Milky Way, it will lose all its gas and dust, and so not be able to generate stars later in life. It will become a gas-poor galaxy with an old population of red stars.

text: Based on the description of these objects, it appears that Arp originally thought that the elliptical galaxies were pushing away spiral arms in companion galaxies. However, the tidal spiral arms may actually look distorted because of the interaction. Some of these "repelled" spiral arms are on the opposite side of the spiral galaxy from the elliptical galaxy. Simulations have shown that such features can be formed through gravitational interactions alone; no repelling forces are needed.

text: The constellation of Andromeda lies well away from the galactic plane, so it does not contain any of the open clusters or bright nebulae of the Milky Way. Because of its distance in the sky from the band of obscuring dust, gas, and abundant stars of our home galaxy, Andromeda's borders contain many visible distant galaxies. The most famous deep-sky object in Andromeda is the spiral galaxy cataloged as Messier 31 (M31) or NGC 224 but known colloquially as the Andromeda Galaxy  for the constellation. M31 is one of the most distant objects visible to the naked eye, 2.2 million light-years from Earth (estimates range up to 2.5 million light-years); it is seen under a dark, transparent sky as a hazy patch in the north of the constellation. M31 is the largest neighboring galaxy to the Milky Way and the largest member of the Local Group of galaxies. In absolute terms, M31 is approximately 200,000 light-years in diameter, twice the size of the Milky Way. It is an enormous – 192.4 by 62.2 arcminutes in apparent size – barred spiral galaxy similar in form to the Milky Way and at an approximate magnitude of 3.5, is one of the brightest deep-sky objects in the northern sky. Despite being visible to the naked eye, the "little cloud" near Andromeda's figure was not recorded until AD 964, when the Arab astronomer al-Sufi wrote his Book of Fixed Stars. M31 was first observed telescopically shortly after its invention, by Simon Marius in 1612.

text: The constellation of Andromeda lies well away from the

text: galactic plane

text: , so it does not contain any of the

text: open cluster

text: s or bright

text: nebula

text: e of the Milky Way. Because of its distance in the sky from the band of obscuring dust, gas, and abundant stars of our home galaxy, Andromeda's borders contain many visible distant galaxies. The most famous

text: deep-sky object

text: in Andromeda is the

text: spiral galaxy

text: cataloged as Messier 31 (M31) or NGC 224 but known colloquially as the

text: Andromeda Galaxy

text: for the constellation. M31 is one of the most distant objects visible to the naked eye, 2.2 million light-years from Earth (estimates range up to 2.5 million light-years); it is seen under a dark, transparent sky as a hazy patch in the north of the constellation. M31 is the largest neighboring galaxy to the Milky Way and the largest member of the

text: Local Group

text: of galaxies. In absolute terms, M31 is approximately 200,000 light-years in diameter, twice the size of the Milky Way. It is an enormous – 192.4 by 62.2 arcminutes in

text: apparent size

text: barred spiral galaxy

text: similar in form to the Milky Way and at an approximate magnitude of 3.5, is one of the brightest deep-sky objects in the northern sky. Despite being visible to the naked eye, the "little cloud" near Andromeda's figure was not recorded until AD 964, when the Arab astronomer

text: al-Sufi

text: wrote his

text: Book of Fixed Stars

text: . M31 was first observed telescopically shortly after its invention, by

text: Simon Marius

text: in 1612.

text: The Milky Way has several smaller galaxies gravitationally bound to it, as part of the Milky Way subgroup, which is part of the local galaxy cluster, the Local Group.

text: The

text: Milky Way

text: has several smaller

text: galaxies gravitationally bound to it

text: , as part of the Milky Way

text: subgroup

text: , which is part of the local galaxy cluster, the

text: Local Group

text: Corona Borealis contains few galaxies observable with amateur telescopes. NGC 6085 and 6086 are a faint spiral and elliptical galaxy respectively close enough to each other to be seen in the same visual field through a telescope. Abell 2142 is a huge (six million light-year diameter), X-ray luminous galaxy cluster that is the result of an ongoing merger between two galaxy clusters. It has a redshift of 0.0909 (meaning it is moving away from us at 27,250 km/s) and a visual magnitude of 16.0. It is about 1.2 billion light-years away. Another galaxy cluster in the constellation, RX J1532.9+3021, is approximately 3.9 billion light-years from Earth. At the cluster's center is a large elliptical galaxy containing one of the most massive and most powerful supermassive black holes yet discovered.  Abell 2065 is a highly concentrated galaxy cluster containing more than 400 members, the brightest of which are 16th magnitude; the cluster is more than one billion light-years from Earth. On a larger scale still, Abell 2065, along with Abell 2061, Abell 2067, Abell 2079, Abell 2089, and Abell 2092, make up the Corona Borealis Supercluster. Another galaxy cluster, Abell 2162, is a member of the Hercules Superclusters.

text: Corona Borealis contains few galaxies observable with amateur telescopes.

text: NGC 6085

text: and

text: are a faint

text: spiral

text: and

text: elliptical galaxy

text: respectively close enough to each other to be seen in the same visual field through a telescope.

text: Abell 2142

text: is a huge (six million light-year diameter),

text: X-ray

text: luminous

text: galaxy cluster

text: that is the result of an ongoing merger between two galaxy clusters. It has a

text: redshift

text: of 0.0909 (meaning it is moving away from us at 27,250 km/s) and a visual magnitude of 16.0. It is about 1.2

text: billion

text: light-years away. Another galaxy cluster in the constellation, RX J1532.9+3021, is approximately 3.9 billion

text: light-year

text: s from Earth. At the cluster's center is a large elliptical galaxy containing one of the

text: most massive

text: and most powerful

text: supermassive black hole

text: s yet discovered.

text: Abell 2065

text: is a highly concentrated galaxy cluster containing more than 400 members, the brightest of which are 16th magnitude; the cluster is more than one billion light-years from Earth. On a larger scale still, Abell 2065, along with

text: Abell 2061

text: Abell 2067

text: Abell 2079

text: Abell 2089

text: , and

text: Abell 2092

text: , make up the

text: Corona Borealis Supercluster

text: . Another galaxy cluster,

text: Abell 2162

text: , is a member of the

text: Hercules Superclusters

text: DDO 169 (also known as UGC 8331) is an irregular galaxy located in the constellation Canes Venatici. It is a member of the M51 Group of galaxies and measures approximately 5 x 1.5 kiloparsecs (16,000 x 5,000 lightyears). The galaxy's large-scale structure is very unorganized and it has two clusters of stars in its outer portions in addition to the cluster in the center. These clusters make it practically impossible to determine the galaxy's rotation curve and contributes to a large variation in distance figures that are derived with different methods. The exact distance to the galaxy is not known, although a 1998 paper estimated the distance as 8.23 megaparsecs.

text: DDO 169 (also known as UGC 8331) is an

text: irregular galaxy

text: located in the constellation

text: Canes Venatici

text: . It is a member of the

text: M51 Group

text: of galaxies and measures approximately 5 x 1.5

text: kiloparsecs

text: (16,000 x 5,000

text: lightyears

text: ). The galaxy's large-scale structure is very unorganized and it has two clusters of stars in its outer portions in addition to the cluster in the center. These clusters make it practically impossible to determine the galaxy's

text: rotation curve

text: and contributes to a large variation in distance figures that are derived with different methods. The exact distance to the galaxy is not known, although a 1998 paper estimated the distance as 8.23

text: megaparsec

text: s.

text: These studies also suggest that M33, the Triangulum Galaxy—the third largest and brightest galaxy of the Local Group—will participate in this event too. Its most likely fate is to end up orbiting the merger remnant of the Milky Way and Andromeda galaxies and finally to merge with it in an even further future, but a collision with the Milky Way before it collides with the Andromeda Galaxy or being ejected from the Local Group cannot be ruled out.

text: These studies also suggest that M33, the

text: Triangulum Galaxy

text: —the third largest and brightest galaxy of the Local Group—will participate in this event too. Its most likely fate is to end up orbiting the merger remnant of the Milky Way and Andromeda galaxies and finally to merge with it in an even further future, but a collision with the Milky Way before it collides with the Andromeda Galaxy or being ejected from the Local Group cannot be ruled out.

text: The Milky Way and Andromeda galaxies each contain a central supermassive black hole, these being Sagittarius A* (ca. ) and an object within the P2 concentration of Andromeda's nucleus (). These black holes will converge near the center of the newly formed galaxy, transferring orbital energy to stars that will be moved to higher orbits by gravitationally interacting with them, in a process that may take millions of years. When they come within one light year of one another, they will emit gravitational waves that will radiate further orbital energy until they merge completely. Gas taken up by the combined black hole could create a luminous quasar or an active galactic nucleus. As of 2006, simulations indicated that the Sun might be brought near the center of the combined galaxy, potentially coming near one of the black holes before being ejected entirely out of the galaxy.

text: The Milky Way and Andromeda galaxies each contain a central

text: supermassive black hole

text: , these being

text: Sagittarius A*

text: (ca. ) and an object within the

text: P2 concentration of Andromeda's nucleus

text: (). These black holes will converge near the center of the newly formed galaxy, transferring

text: orbital energy

text: to stars that will be moved to higher orbits by gravitationally interacting with them, in a process that may take millions of years. When they come within one light year of one another, they will emit

text: gravitational wave

text: s that will radiate further orbital energy until they merge completely. Gas taken up by the combined black hole could create a luminous

text: quasar

text: or an

text: active galactic nucleus

text: . As of 2006, simulations indicated that the Sun might be brought near the center of the combined galaxy, potentially coming near one of the black holes before being ejected entirely out of the galaxy.

text: NGC 5474 is a  peculiar dwarf galaxy in the constellation Ursa Major.  It is one of several companion galaxies of the Pinwheel Galaxy (M101), a grand-design spiral galaxy.Among the Pinwheel Galaxy's companions, this galaxy is the closest to the Pinwheel Galaxy itself.  The gravitational interaction between NGC 5474 and the Pinwheel Galaxy have strongly distorted the galaxy.  As a result, the disk is offset relative to the nucleus.  The star formation in this galaxy (as traced by hydrogen spectral line emission) is also offset from the nucleus. NGC 5474 shows some signs of a spiral structure. As a result, this galaxy is often classified as a dwarf spiral galaxy, a relatively rare group of dwarf galaxies.

text: NGC 5474 is a

text: peculiar

text: dwarf galaxy

text: in the

text: constellation

text: Ursa Major

text: .  It is one of several companion galaxies of the

text: Pinwheel Galaxy (M101)

text: , a

text: grand-design spiral galaxy

text: .Among the Pinwheel Galaxy's companions, this galaxy is the closest to the Pinwheel Galaxy itself.  The gravitational interaction between NGC 5474 and the Pinwheel Galaxy have strongly distorted the galaxy.  As a result, the

text: disk

text: is offset relative to the

text: nucleus

text: .  The star formation in this galaxy (as traced by

text: hydrogen

text: spectral line

text: emission) is also offset from the nucleus. NGC 5474 shows some signs of a spiral structure. As a result, this galaxy is often classified as a

text: dwarf spiral galaxy

text: , a relatively rare group of dwarf galaxies.

text: Active elliptical galaxies of a form similar to M87 are believed to form as a result of one or more mergers between smaller galaxies. There is now little dust remaining to form the diffuse nebulae where new stars are created, so the stellar population is dominated by old, population II stars that contain relatively low abundances of elements other than hydrogen and helium. The elliptical shape of this galaxy is maintained by random orbital motions of its member stars, in contrast to the more orderly rotational motions found in a spiral galaxy such as the Milky Way.

text: Active elliptical galaxies of a form similar to M87 are believed to form as a result of one or more mergers between smaller galaxies. There is now little dust remaining to form the

text: diffuse nebula

text: e where new stars are created, so the stellar population is dominated by old,

text: population II

text: stars that contain relatively low abundances of elements other than hydrogen and helium. The elliptical shape of this galaxy is maintained by random orbital motions of its member stars, in contrast to the more orderly rotational motions found in a

text: spiral galaxy

text: such as the Milky Way.

text: This gives clues as to the composition of the ISM in the various galaxies.  Previously, the different average extinction curves in the Milky Way, LMC, and SMC were thought to be the result of the different metallicities of the three galaxies: the LMC's metallicity is about 40% of that of the Milky Way, while the SMC's is about 10%.  Finding extinction curves in both the LMC and SMC which are similar to those found in the Milky Way and finding extinction curves in the Milky Way that look more like those found in the LMC2 supershell of the LMC and in the SMC Bar has given rise to a new interpretation.  The variations in the curves seen in the Magellanic Clouds and Milky Way may instead be caused by processing of the dust grains by nearby star formation.  This interpretation is supported by work in starburst galaxies (which are undergoing intense star formation episodes) that their dust lacks the 2175 Å bump.

text: This gives clues as to the composition of the ISM in the various galaxies.  Previously, the different average extinction curves in the Milky Way, LMC, and SMC were thought to be the result of the different

text: metallicities

text: of the three galaxies: the LMC's metallicity is about 40% of that of the

text: Milky Way

text: , while the SMC's is about 10%.  Finding extinction curves in both the LMC and SMC which are similar to those found in the Milky Way and finding extinction curves in the Milky Way that look more like those found in the LMC2 supershell of the LMC and in the SMC Bar has given rise to a new interpretation.  The variations in the curves seen in the Magellanic Clouds and Milky Way may instead be caused by processing of the dust grains by nearby star formation.  This interpretation is supported by work in starburst galaxies (which are undergoing intense star formation episodes) that their dust lacks the 2175 Å bump.

text: NGC 4088 is a grand design spiral galaxy.  This means that the spiral arms in the galaxy's disk are sharply defined.  In visible light, one of the spiral arms appears to have a disconnected segment. Halton Arp included this galaxy in the Atlas of Peculiar Galaxies as one of several examples where this phenomenon occurs.

text: NGC 4088 is a grand design spiral galaxy.  This means that the spiral arms in the galaxy's disk are sharply defined.  In visible light, one of the spiral arms appears to have a disconnected segment.

text: Halton Arp

text: included this galaxy in the

text: Atlas of Peculiar Galaxies

text: as one of several examples where this phenomenon occurs.

text: O type main-sequence stars and the most massive of the B type blue-white stars become supergiants. Because of their extreme masses they have short lifespans of 30 million years down to a few hundred thousand years. They are mainly observed in young galactic structures such as open clusters, the arms of spiral galaxies, and in irregular galaxies. They are less abundant in spiral galaxy bulges, and are rarely observed in elliptical galaxies, or globular clusters, which are composed mainly of old stars.

text: O type main-sequence stars and the most massive of the B type blue-white stars become supergiants. Because of their extreme masses they have short lifespans of 30 million years down to a few hundred thousand years. They are mainly observed in young galactic structures such as

text: open cluster

text: s, the arms of

text: spiral galaxies

text: , and in

text: irregular galaxies

text: . They are less abundant in spiral galaxy bulges, and are rarely observed in

text: elliptical galaxies

text: , or

text: globular cluster

text: s, which are composed mainly of old stars.

text: Mainstream astronomical theory before Galaxy Zoo held that elliptical (or 'early type') galaxies were red in color and spiral (or 'late type') galaxies were blue in color: several papers published as a result of Galaxy Zoo have proved otherwise. A population of blue ellipticals was found. These are galaxies which have changed their shape from spiral to oval, but still have young stars in them. Indeed, Galaxy Zoo came about through Schawinski's searching for blue elliptical galaxies, as near the end of 2006, he had spent most of his waking hours trying to find these rare galaxies. Blueness in galaxies means that new stars are forming. However ellipticals are almost always red, indicating that they are full of old and dead stars. Thus, blue ellipticals are paradoxical, but give clues to star-formation in different types of galaxies.

text: Mainstream astronomical theory before Galaxy Zoo held that

text: elliptical

text: (or 'early type') galaxies were red in color and

text: spiral

text: (or 'late type') galaxies were blue in color: several papers published as a result of Galaxy Zoo have proved otherwise. A population of blue ellipticals was found. These are galaxies which have changed their shape from spiral to oval, but still have young stars in them. Indeed, Galaxy Zoo came about through Schawinski's searching for blue elliptical galaxies, as near the end of 2006, he had spent most of his waking hours trying to find these rare galaxies. Blueness in galaxies means that new stars are forming. However ellipticals are almost always red, indicating that they are full of old and dead stars. Thus, blue ellipticals are paradoxical, but give clues to star-formation in different types of galaxies.

text: The Chandra X-ray Observatory, originating at MSFC, was launched on July 3, 1999, and is operated by the Smithsonian Astrophysical Observatory. With an angular resolution of 0.5 arcsecond (2.4 µrad), it has a thousand times better resolution than the first orbiting X-ray telescopes. Its highly eliptical orbit allows continuous observations up to 85 percent of its 65-hour orbital period. With its ability to make X-ray images of star clusters, supernova remnants, galactic eruptions, and collisions between clusters of galaxies - in its first decade of operation it has transformed astronomer's view of the high-energy universe.

text: The

text: Chandra X-ray Observatory

text: , originating at MSFC, was launched on July 3, 1999, and is operated by the

text: Smithsonian Astrophysical Observatory

text: . With an

text: angular resolution

text: of 0.5

text: arcsecond

text: (2.4 µrad), it has a thousand times better resolution than the first orbiting X-ray telescopes. Its highly

text: eliptical

text: orbit allows continuous observations up to 85 percent of its 65-hour

text: orbital period

text: . With its ability to make X-ray images of star clusters, supernova remnants, galactic eruptions, and collisions between clusters of galaxies - in its first decade of operation it has transformed astronomer's view of the high-energy universe.

text: NGC 3227 is an intermediate spiral galaxy that is interacting with the dwarf elliptical galaxy NGC 3226.  The two galaxies are one of several examples of a spiral with a dwarf elliptical companion that are listed in the Atlas of Peculiar Galaxies.  Both galaxies may be found in the constellation Leo.

text: NGC 3227 is an

text: intermediate spiral galaxy

text: that is interacting with the

text: dwarf elliptical galaxy

text: NGC 3226

text: Atlas of Peculiar Galaxies

text: .  Both galaxies may be found in the

text: constellation

text: Leo

text: Interferometric measurements of stellar positions over the course of the mission would have permitted SIM to precisely measure the distances between stars throughout the Milky Way. This would have allowed astronomers to create a "roadmap" of the Galaxy which will answer many questions about its shape and size.

text: Interferometric measurements of stellar positions over the course of the mission would have permitted SIM to precisely measure the distances between stars throughout the

text: Milky Way

text: . This would have allowed astronomers to create a "roadmap" of the Galaxy which will answer many questions about its shape and size.

text: IC 10 is an irregular galaxy in the constellation Cassiopeia. It was discovered by Lewis Swift in 1887 and in 1935 Nicholas Mayall became the first to suggest that the object is extragalactic. Edwin Hubble suspected it might belong to the Local Group of galaxies, but its status remained uncertain for decades. The radial velocity of IC 10 was measured in 1962, and it was found to be approaching the Milky Way at approximately350 km/s, strengthening the evidence for its membership in the Local Group. Its membership in the group was finally confirmed in 1996 by direct measurements of itsdistance based on observations of Cepheids. Despite its closeness, the galaxy is rather difficult to study because it lies near the plane of the Milky Way and is therefore heavily obscured by interstellar matter.

text: IC 10 is an

text: irregular galaxy

text: in the

text: constellation

text: Cassiopeia

text: . It was discovered by

text: Lewis Swift

text: in 1887 and in 1935

text: Nicholas Mayall

text: became the first to suggest that the object is extragalactic.

text: Edwin Hubble

text: suspected it might belong to the

text: Local Group

text: of

text: galaxies

text: , but its status remained uncertain for decades. The

text: radial velocity

text: of IC 10 was measured in 1962, and it was found to be approaching the

text: Milky Way

text: at approximately350 km/s, strengthening the evidence for its membership in the Local Group. Its membership in the group was finally confirmed in 1996 by direct measurements of itsdistance based on observations of

text: Cepheid

text: s. Despite its closeness, the galaxy is rather difficult to study because it lies near the plane of the

text: Milky Way

text: and is therefore heavily obscured by

text: interstellar matter

text: One of the nearest Dwarf elliptical galaxies is M32, a satellite of the Andromeda Galaxy. In 1944 Walter Baade confirmed dwarf ellipticals NGC 147 and NGC 185 as members of the Local Group by resolving them into individual stars, thanks to their relatively little distance. In the 1950s, dEs were also discovered in the nearby Fornax and Virgo clusters.

text: One of the nearest Dwarf elliptical galaxies is

text: , a satellite of the

text: Andromeda Galaxy

text: . In 1944

text: Walter Baade

text: confirmed dwarf ellipticals

text: NGC 147

text: and

text: NGC 185

text: as members of the

text: Local Group

text: by resolving them into individual stars, thanks to their relatively little distance. In the 1950s, dEs were also discovered in the nearby

text: Fornax

text: and

text: Virgo clusters

text: The Church later appeared in a Guardians of the Galaxy storyline, where it was governed by the Protégé and controlled a large portion of the Milky Way. The Skrull heroine Replica was a devout member. She would later give herself to Protégé in order to save the Guardians.

text: The Church later appeared in a

text: Guardians of the Galaxy

text: storyline, where it was governed by the

text: Protégé

text: and controlled a large portion of the

text: Milky Way

text: . The

text: Skrull

text: heroine

text: Replica

text: was a devout member. She would later give herself to Protégé in order to save the Guardians.

text: A peculiar galaxy is a galaxy which is unusual in its size, shape, or composition. Peculiar galaxies come about as a result of  interactions between galaxies, and they may contain atypical amounts of dust or gas, may have higher or lower surface brightness than a typical galaxy, or may have features such as nuclear jets. They can be highly irregular in shape due to the immense gravitational forces which act on them during encounters with other galaxies. They are the result of recent mergers between two or more normal (i.e. spiral galaxies, elliptical galaxies, etc.) galaxies. Specifically, Peculiar galaxies may be from galaxy mergers and collisions that happened in the recent past. Peculiar galaxies are of similar size to regular sized Spiral and Elliptical galaxies, and seem to have features and properties similar to these galaxy types. Astronomers have identified two types of peculiar galaxies, interacting galaxies and active galactic nuclei (AGN). Also, during collisions it is expected that there would be a spike in activity such as star formation or ignition of the nucleus of one or both galaxies; a common property of Peculiar galaxies as well. Peculiar galaxies are designated by "p" or "pec" in some catalogs. They are snapshots of galaxy mergers in the first millions of years after the collision. That's when the resulting galaxy is in an active state and still maintains some common features of the host galaxies. They constitute between 5% and 10% of the known galaxy population, although most ‘normal’ galaxies will show peculiar features if examined carefully. Peculiar galaxies show a great diversity of form. The vast majority can be attributed to strong gravitational tides generated in the close passage of two galaxies, to the extent that the terms ‘peculiar galaxy’ and ‘interacting galaxy’ are now virtually synonymous. Many peculiar galaxies are experiencing episodes of enhanced star formation, called starbursts. They also show a greater tendency to host ACTIVE GALACTIC NUCLEI (AGN) compared with the normal galaxy population

text: A peculiar galaxy is a

text: galaxy

text: which is unusual in its size, shape, or composition. Peculiar galaxies come about as a result of  interactions between galaxies, and they may contain atypical amounts of dust or gas, may have higher or lower surface brightness than a typical galaxy, or may have features such as nuclear

text: jets

text: . They can be highly irregular in shape due to the immense

text: gravitational

text: The presence of a dwarf galaxy in the vicinity of BX442 offers a clue as to how the premature spiral structure may have emerged in what would otherwise be a somewhat chaotic lumpy collection of stars, as is the case with most other early galaxies. A recent study of one of the satellite galaxies of the Milky Way, known as the Sagittarius Dwarf Elliptical Galaxy (SagDEG), suggest that SagDEG may have helped generate some the Milky Way's spiral structure when it passed repeatedly through the plane of our galaxy over the past few hundred million years.  Similarly, many of the most well-known grand design spiral galaxies (such as the Whirlpool Galaxy) also have nearby companions.  A computer simulation has shown that the dwarf companion of BX442 could have had the same effect. However, the chaotic motions of the stars in the youthful BX442 suggest that, if this is the case, the present spiral structure will not be long-lived in cosmic terms, and may have disappeared within a hundred million years or so.

text: The presence of a dwarf galaxy in the vicinity of BX442 offers a clue as to how the premature spiral structure may have emerged in what would otherwise be a somewhat chaotic lumpy collection of stars, as is the case with most other early galaxies. A recent study of one of the satellite galaxies of the Milky Way, known as the Sagittarius Dwarf Elliptical Galaxy (

text: SagDEG

text: ), suggest that SagDEG may have helped generate some the Milky Way's spiral structure when it passed repeatedly through the plane of our galaxy over the past few hundred million years.  Similarly, many of the most well-known grand design spiral galaxies (such as the

text: Whirlpool Galaxy

text: ) also have nearby companions.  A computer simulation has shown that the dwarf companion of BX442 could have had the same effect. However, the chaotic motions of the stars in the youthful BX442 suggest that, if this is the case, the present spiral structure will not be long-lived in cosmic terms, and may have disappeared within a hundred million years or so.

text: Unlike most spiral galaxies, NGC 4618 has a single spiral arm, which gives the galaxy an asymmetric appearance.  This galaxy was included in the Atlas of Peculiar Galaxies as one of three examples of nearby galaxies with single spiral arms. Although NGC 4618 is labeled as peculiar, many similar galaxies have been identified.

text: Unlike most

text: spiral galaxies

text: , NGC 4618 has a single

text: spiral arm

text: , which gives the galaxy an asymmetric appearance.  This galaxy was included in the

text: Atlas of Peculiar Galaxies

text: as one of three examples of nearby galaxies with single spiral arms. Although NGC 4618 is labeled as peculiar, many similar galaxies have been identified.

text: Whether searching to limit the stress or the deformation, macrostructure, structural element and microstructure have each, a weight Vρ, when ρ is the volumic weight of materials, in N/m³, function of the sollicitations {F} (for "force" in général) applied to them, of their size {L} (for length or "size" in general) , of their shape {G} (for geometry or "shape" in general), and of their constituting material {M} (for "material" in general).

text: Rainer Spurzem is a German astronomer at the Astronomisches Rechen-Institut in Heidelberg, Germany. His speciality is the N-body simulation of galaxies and star clusters.

text: Rainer Spurzem is a

text: German

text: astronomer

text: at the

entity_name: Astronomical Calculation Institute (Heidelberg University)

text: Astronomisches Rechen-Institut

text: in

text: Heidelberg

text: , Germany. His speciality is the

text: N-body simulation

text: of

text: galaxies

text: and

text: star clusters

text: NGC 4088 and NGC 4085 are members of the M109 Group, a group of galaxies located in the constellation Ursa Major.  This large group contains between 41 and 58 galaxies, including the spiral galaxy M109.

text: NGC 4088 and NGC 4085 are members of the

text: M109 Group

text: , a

text: group of galaxies

text: located in the

text: constellation

text: Ursa Major

text: .  This large group contains between 41 and 58 galaxies, including the

text: spiral galaxy

text: NGC 7753 is the primary galaxy.  It is a barred spiral galaxy with a small nucleus.  NGC 7752 is the satellite galaxy of NGC 7753.  It is a barred lenticular galaxy that is apparently attached to one of NGC 7753's spiral arms, it would resemble the Whirlpool Galaxy (M51A) and its satellite NGC 5195 (M51B).  On January 2, 2006, a supernova (SN 2006A) was observed in NGC 7753.  It was the only supernova observed in the NGC 7752 and NGC 7753 galaxies (so far).

text: NGC 7753 is the primary galaxy.  It is a

text: barred spiral galaxy

text: with a small nucleus.  NGC 7752 is the

text: satellite galaxy

text: of NGC 7753.  It is a

text: barred lenticular galaxy

text: that is apparently attached to one of NGC 7753's

text: spiral arm

text: s, it would resemble the

text: Whirlpool Galaxy

text: (M51A) and its satellite

text: NGC 5195

text: (M51B).  On January 2, 2006, a

text: supernova

text: SN 2006A

text: ) was observed in NGC 7753.  It was the only supernova observed in the NGC 7752 and NGC 7753 galaxies (so far).

text: th cluster of galaxies with common expected velocity. In this case it is far from obvious how to determine a priori how many clusters (of common velocities) there should be and any model for this would be highly suspect and should be checked against the data. By using a Dirichlet process prior for the distribution of cluster means we circumvent the need to explicitly specify ahead of time how many clusters there are, although the concentration parameter still controls it implicitly.

text: Some of the irregular galaxies, especially of the Magellanic type, are small spiral galaxies that are being distorted by the gravity of a larger neighbor.

text: Some of the irregular galaxies, especially of the

text: Magellanic type

text: , are small

text: spiral galaxies

text: that are being distorted by the gravity of a larger neighbor.

text: By plotting the turnoff point of the stars in star clusters, one can estimate the cluster's age.

text: By plotting the turnoff point of the stars in

text: star clusters

text: , one can estimate the cluster's age.

text: Under the auspices of SETI's Project Phoenix, scientists Margaret Turnbull and Jill Tarter developed the "HabCat" (or Catalogue of Habitable Stellar Systems) in 2002. The catalogue was formed by winnowing the nearly 120,000 stars of the larger Hipparcos Catalogue into a core group of 17,000 "HabStars", and the selection criteria that were used provide a good starting point for understanding which astrophysical factors are necessary to habitable planets. According to research published in August 2015, very large galaxies may be more favorable to the formation and development of habitable planets than smaller galaxies, like the Milky Way galaxy.

text: Under the auspices of

entity_name: Search for extraterrestrial intelligence

text: SETI

text: 's

text: Project Phoenix

text: , scientists

text: Margaret Turnbull

text: and

text: Jill Tarter

text: developed the "

text: HabCat

text: " (or Catalogue of Habitable Stellar Systems) in 2002. The catalogue was formed by winnowing the nearly 120,000 stars of the larger

text: Hipparcos Catalogue

text: into a core group of 17,000 "HabStars", and the selection criteria that were used provide a good starting point for understanding which astrophysical factors are necessary to habitable planets. According to research published in August 2015, very large galaxies may be more favorable to the formation and development of habitable planets than smaller galaxies, like the

text: Milky Way

text: galaxy.

text: Ultra-compact dwarf galaxies (UCD) are a  class of very compact galaxies with very high stellar populations, discovered in the 2000s. They are thought to be on the order of 200 light years across, containing about 100 million stars. It is theorised that these are the cores of nucleated dwarf elliptical galaxies that have been stripped of gas and outlying stars by tidal interactions, travelling through the hearts of rich clusters. UCDs have been found in the Virgo Cluster, Fornax Cluster, Abell 1689, and the Coma Cluster, amongst others. In particular, an unprecedentedly large sample of ~ 100 UCDs has been found in the core region of the Virgo cluster by the Next Generation Virgo Cluster Survey team. The first ever relatively robust studies of the global properties of Virgo UCDs suggest that UCDs have distinct dynamical and structural properties from normal globular clusters. An extreme  example of UCD is M60-UCD1, about 54 million light years away, which contains approximately 200 million solar masses within a 160 light year radius; its central region packs in stars about 25 times closer together than stars in Earth's region in the Milky Way.  M59-UCD3 is approximately the same size as M60-UCD1 with a half-light radius, r, of approximately 20 parsecs but is 40% more luminous with an apparent relative magnitude of approximately −14.6.  This makes M59-UCD3 the densest known galaxy.

text: Ultra-compact dwarf galaxies (UCD) are a  class of very compact galaxies with very high stellar populations, discovered in the 2000s. They are thought to be on the order of 200 light years across, containing about 100 million stars. It is theorised that these are the cores of nucleated dwarf elliptical galaxies that have been stripped of gas and outlying stars by

text: tidal interactions

text: , travelling through the hearts of rich clusters. UCDs have been found in the

text: Virgo Cluster

text: Fornax Cluster

text: Abell 1689

text: , and the

text: Coma Cluster

text: , amongst others. In particular, an unprecedentedly large sample of ~ 100 UCDs has been found in the core region of the Virgo cluster by the

text: Next Generation Virgo Cluster Survey

text: team. The first ever relatively robust studies of the global properties of Virgo UCDs suggest that UCDs have distinct dynamical and structural properties from normal globular clusters. An extreme  example of UCD is

text: , about 54 million light years away, which contains approximately 200 million solar masses within a 160 light year radius; its central region packs in stars about 25 times closer together than stars in Earth's region in the Milky Way.

text: is approximately the same size as M60-UCD1 with a half-light radius, r, of approximately 20

text: parsecs

text: but is 40% more luminous with an apparent relative magnitude of approximately −14.6.  This makes M59-UCD3 the densest known galaxy.

text: Raindrops have sizes ranging from  mean diameter, above which they tend to break up. Smaller drops are called cloud droplets, and their shape is spherical. As a raindrop increases in size, its shape becomes more oblate, with its largest cross-section facing the oncoming airflow. Large rain drops become increasingly flattened on the bottom, like hamburger buns; very large ones are shaped like parachutes. Contrary to popular belief, their shape does not resemble a teardrop. The biggest raindrops on Earth were recorded over Brazil and the Marshall Islands in 2004 — some of them were as large as . The large size is explained by condensation on large smoke particles or by collisions between drops in small regions with particularly high content of liquid water.

text: Raindrops have sizes ranging from  mean diameter, above which they tend to break up. Smaller drops are called cloud droplets, and their shape is spherical. As a raindrop increases in size, its shape becomes more oblate, with its largest cross-section facing the oncoming airflow. Large rain drops become increasingly flattened on the bottom, like

text: hamburger

text: buns; very large ones are shaped like

text: parachute

text: s. Contrary to popular belief, their shape does not resemble a teardrop. The biggest raindrops on Earth were recorded over

text: Brazil

text: and the

text: Marshall Islands

text: in 2004 — some of them were as large as . The large size is explained by condensation on large

text: smoke

text: particles or by collisions between drops in small regions with particularly high content of liquid water.

text: Life without complex chemistry is unknown.  Such chemistry requires metals, namely elements other than hydrogen or helium and thereby suggests that a planetary system rich in metals is a necessity for life. The only known mechanism for creating and dispersing metals is a supernova explosion. The absorption spectrum of a star reveals the presence of metals within, and studies of stellar spectra reveal that many, perhaps most, stars are poor in metals. Low metallicity characterizes the early universe: globular clusters and other stars that formed when the universe was young, stars in most galaxies other than large spirals, and stars in the outer regions of all galaxies.  Metal-rich central stars capable of supporting complex life are therefore believed to be most common in the quiet suburbs of the larger spiral galaxies—where radiation also happens to be weak.

text: Life without complex chemistry is unknown.  Such chemistry requires

text: metals

text: , namely elements other than hydrogen or helium and thereby suggests that a planetary system rich in

text: metals

text: is a necessity for life. The only known mechanism for creating and dispersing metals is a

text: supernova

text: explosion. The

text: absorption spectrum

text: of a star reveals the presence of metals within, and studies of stellar spectra reveal that many, perhaps most, stars are poor in metals. Low metallicity characterizes the early universe: globular clusters and other stars that formed when the universe was young, stars in most galaxies other than large

text: spirals

text: , and stars in the outer regions of all galaxies.  Metal-rich central stars capable of supporting complex life are therefore believed to be most common in the quiet suburbs of the larger spiral galaxies—where radiation also happens to be weak.

text: Some UDGs found in the Coma Cluster, about 330 million light years from Earth, have diameters of  (more than half the size of our galaxy) with 1% of the stars of the Milky Way Galaxy. The distribution of ultra diffuse galaxies in the Coma Cluster is the same as luminous galaxies; this suggests that the cluster environment strips the gas from the galaxies, while allowing them to populate the cluster the same as more luminous galaxies. The similar distribution in the higher tidal force zones suggests a larger dark matter fraction to hold the galaxies together under the higher stress.

text: Some UDGs found in the

text: Coma Cluster

text: , about 330 million light years from Earth, have diameters of  (more than half the size of our galaxy) with 1% of the stars of the

text: Milky Way Galaxy

text: . The distribution of ultra diffuse galaxies in the Coma Cluster is the same as luminous galaxies; this suggests that the cluster environment strips the gas from the galaxies, while allowing them to populate the cluster the same as more luminous galaxies. The similar distribution in the higher tidal force zones suggests a larger dark matter fraction to hold the galaxies together under the higher stress.

text: Observations with the Hubble Space Telescope show an elliptical galaxy with blobs and a filamentary structure. The radio jets being generated by the active galactic nucleus are interacting with the interstellar medium, producing extended narrow line regions. These features are commonly associated with many active galaxies.  The axial ratio of the elliptical galaxy is 1.4, meaning it is about 1.4 times large along the primary axis than along the perpendicular axis.

text: Observations with the

text: Hubble Space Telescope

text: show an

text: elliptical galaxy

text: with blobs and a filamentary structure. The radio jets being generated by the

text: active galactic nucleus

text: are interacting with the

text: interstellar medium

text: , producing extended narrow line regions. These features are commonly associated with many active galaxies.  The axial ratio of the elliptical galaxy is 1.4, meaning it is about 1.4 times large along the primary axis than along the perpendicular axis.

text: There is a certain process used to recover materials from appliances. Parts are generally removed in order from largest to smallest. Metals are extracted first and then plastics. Materials are sorted by either size, shape, or density. Sizing is a good means of sorting to quicken future processing. It also classifies fractions that show composition. Materials report to larger or finer fractions based on original dimension, toughness, or brittleness. Shape classification contributes to the dynamics of the material. Classification by density is important when it comes to determining the use of a material.

text: There is a certain process used to recover materials from appliances. Parts are generally removed in order from largest to smallest. Metals are extracted first and then plastics. Materials are sorted by either size, shape, or

text: density

text: . Sizing is a good means of sorting to quicken future processing. It also classifies fractions that show composition. Materials report to larger or finer fractions based on original dimension, toughness, or brittleness. Shape classification contributes to the dynamics of the material. Classification by density is important when it comes to determining the use of a material.

text: Galaxies have random rotations and inclinations. As a result, the shear effects in weak lensing need to be determined by statistically preferred orientations. The primary source of error in lensing measurement is due to the convolution of the PSF with the lensed image. The KSB method measures the ellipticity of a galaxy image. The shear is proportional to the ellipticity. The objects in lensed images are parameterized according to their weighted quadrupole moments. For a perfect ellipse, the weighted quadrupole moments are related to the weighted ellipticity. KSB calculate how a weighted ellipticity measure is related to the shear and use the same formalism to remove the effects of the PSF.

text: In geometry, two subsets of a Euclidean space have the same shape if one can be transformed to the other by a combination of translations, rotations (together also called rigid transformations), and uniform scalings. In other words, the shape of a set of points is all the geometrical information that is invariant to translations, rotations, and size changes. Having the same shape is an equivalence relation, and accordingly a precise mathematical definition of the notion of shape can be given as being an equivalence class of subsets of a Euclidean space having the same shape.

text: In geometry, two subsets of a

text: Euclidean space

text: have the same shape if one can be transformed to the other by a combination of

text: translations

text: rotation

text: s (together also called

text: rigid transformation

text: s), and

text: uniform scaling

text: s. In other words, the shape of a set of points is all the geometrical information that is invariant to translations, rotations, and size changes. Having the same shape is an

text: equivalence relation

text: , and accordingly a precise mathematical definition of the notion of shape can be given as being an

text: equivalence class

text: of subsets of a Euclidean space having the same shape.

text: The galaxy is located in the constellation Fornax, and is estimated to have contained roughly a billion stars,  although it was only at most one tenth of the diameter of our own galaxy, the Milky Way, and had less than 1% of the mass of the Milky Way's stars. According to Lehnert (of the Observatoire de Paris), it was forming the same number of stars per year as our galaxy, but they were much smaller and less massive, making it "intensely star forming".

text: The galaxy is located in the constellation

text: Fornax

text: , and is estimated to have contained roughly a billion

text: star

text: s,  although it was only at most one tenth of the diameter of our own galaxy, the

text: Milky Way

text: , and had less than 1% of the mass of the Milky Way's stars. According to Lehnert (of the

text: Observatoire de Paris

text: ), it was forming the same number of stars per year as our galaxy, but they were much smaller and less massive, making it "intensely star forming".

text: Apple filed a new U.S. lawsuit in February 2012, asserting Samsung's violation of five Apple patents. The products being cited are: Admire, Galaxy Nexus, Galaxy Note, Galaxy Note II, Galaxy SII, Galaxy SII Epic 4G Touch, Galaxy SII Skyrocket, Galaxy SIII, Galaxy Tab II 10.1, and Stratosphere. Samsung has responded with a counterclaim, in which it states that two patents for nine phones and tablets have been infringed on by Apple. The products that Samsung is citing are: iPhone 4, iPhone 4S, iPhone 5, iPad 2, iPad 3, iPad 4, iPad mini, iPod touch (5th generation), iPod touch (4th generation), and MacBook Pro. Samsung stands to gain US$6 million if the jury rules in its favor, while Apple is seeking US$2 billion in damages and could proceed with similar lawsuits against other Android handset makers, as the relevant patent issues extend beyond Samsung's software technology.

text: KKH 060 is an irregular galaxy and a low surface brightness galaxy located in the direction of the  constellation Leo at a distance of 4.89 million light years from Earth. The galaxy is close to the Local Group, but is not considered to be a member of it.

text: KKH 060 is an

text: irregular galaxy

text: and a

text: low surface brightness galaxy

text: located in the direction of the

text: constellation Leo

text: at a distance of 4.89 million light years from

text: Earth

text: . The galaxy is close to the

text: Local Group

text: , but is not considered to be a member of it.

text: is instantiated as

text: is instantiated as

text: Hubble's early estimate of his constant was 550 km/s/Mpc, and the inverse of that is 1.8 billion years. It was believed by many geologists such as Arthur Holmes in the 1920s that the Earth was probably over 2 billion years old, but with large uncertainty. The possible discrepancy between the ages of the Earth and the universe was probably one motivation for the development of the Steady State theory in 1948 as an alternative to the Big Bang; in the (now obsolete) steady state theory, the universe is infinitely old and on average unchanging with time. The steady state theory postulated spontaneous creation of matter to keep the average density constant as the universe expands, and therefore most galaxies still have an age less than 1/H. However, if H had been 550 km/s/Mpc, our Milky Way galaxy would be exceptionally large compared to most other galaxies, so it could well be much older than an average galaxy, therefore eliminating the age problem.

text: Hubble's early estimate of his constant was 550 km/s/Mpc, and the inverse of that is 1.8 billion years. It was believed by many geologists such as

text: Arthur Holmes

text: in the 1920s that the Earth was probably over 2 billion years old, but with large uncertainty. The possible discrepancy between the ages of the Earth and the universe was probably one motivation for the development of the

text: Steady State theory

text: in 1948 as an alternative to the Big Bang; in the (now obsolete) steady state theory, the universe is infinitely old and on average unchanging with time. The steady state theory postulated spontaneous creation of matter to keep the average density constant as the universe expands, and therefore most galaxies still have an age less than 1/H. However, if H had been 550 km/s/Mpc, our Milky Way galaxy would be exceptionally large compared to most other galaxies, so it could well be much older than an average galaxy, therefore eliminating the age problem.

text: In August 2004 InFocus announced that Ranson who was President and Chief Operation Officer would be the next CEO and a member of the board of directors. He would replace of former Chief Executive Officer and Chairman John Harker who had led the company since 1992, however Harker would continue in the role of Chairman.

text: In August 2004 InFocus announced that Ranson who was President and Chief Operation Officer would be the next CEO and a member of the board of directors. He would replace of former Chief Executive Officer and Chairman

text: John Harker

text: who had led the company since 1992, however Harker would continue in the role of

text: Chairman

text: Coma Berenices contains the northern portion of the Virgo Cluster (also known as the Coma–Virgo Cluster), about 60 million light-years away. The portion includes five Messier galaxies. M85 (NGC 4382), considered elliptical or lenticular, is one of the cluster's brighter members at magnitude nine. M85 is interacting with the spiral galaxy NGC 4394 and the elliptical galaxy MCG-3-32-38. M88 (NGC 4501) is a multi-arm spiral galaxy seen at about 30° from edge-on. It has a highly-regular shape with well-developed, symmetrical arms. Among the first galaxies recognized as spiral, it has a supermassive black hole in its center. M91 (NGC 4548), a barred spiral galaxy with a bright, diffuse nucleus, is the faintest object in Messier's catalog at magnitude 10.2. M98 (NGC 4192), a bright, elongated spiral galaxy seen nearly edge-on, appears elliptical because of its unusual angle. The magnitude-10 galaxy, a member of the Virgo Cluster, has no redshift. M99 (NGC 4254) is a spiral galaxy seen face-on. Like M98 it is a magnitude-10 member of the Virgo Cluster, and has an unusually long arm on its west side. M100 (NGC 4321), a magnitude-nine spiral galaxy seen face-on. is one of the cluster's brightest. Photographs reveal a brilliant core, two prominent spiral arms, an array of secondary arms and several dust lanes.

text: Coma Berenices contains the northern portion of the

text: Virgo Cluster

text: (also known as the Coma–Virgo Cluster), about 60 million light-years away. The portion includes five Messier galaxies.

text: (NGC 4382), considered

text: elliptical

text: or

text: lenticular

text: , is one of the cluster's brighter members at magnitude nine. M85 is interacting with the spiral galaxy

text: NGC 4394

text: and the elliptical galaxy

text: (NGC 4501) is a multi-arm spiral galaxy seen at about 30° from edge-on. It has a highly-regular shape with well-developed, symmetrical arms. Among the first galaxies recognized as spiral, it has a

text: supermassive black hole

text: in its center.

text: (NGC 4548), a

text: barred spiral galaxy

text: with a bright, diffuse nucleus, is the faintest object in Messier's catalog at magnitude 10.2.

text: (NGC 4192), a bright, elongated spiral galaxy seen nearly edge-on, appears elliptical because of its unusual angle. The magnitude-10 galaxy, a member of the Virgo Cluster, has no

text: redshift

text: (NGC 4254) is a

text: spiral galaxy

text: seen face-on. Like M98 it is a magnitude-10 member of the Virgo Cluster, and has an unusually long arm on its west side.

text: (NGC 4321), a magnitude-nine spiral galaxy seen face-on. is one of the cluster's brightest. Photographs reveal a brilliant core, two prominent spiral arms, an array of secondary arms and several

text: dust lane

text: s.

text: In most markets, the program was replaced by Judge Alex; that program also tapes at KRIV.

text: In most markets, the program was replaced by

text: Judge Alex

text: ; that program also tapes at KRIV.

text: After the Wei general Cao Xiu was defeated at Shi Ting, the forces under Lu Xun pursued him. These enemy forces unexpectedly ran into divisions under Zhu Ling and other generals. Surprised by the sudden appearance of Wei forces, the pursuing army fled and Cao Xiu was able to make his escape back to Wei

text: After the Wei general

text: Cao Xiu

text: was

text: defeated at Shi Ting

text: , the forces under

text: Lu Xun

text: pursued him. These enemy forces unexpectedly ran into divisions under Zhu Ling and other generals. Surprised by the sudden appearance of Wei forces, the pursuing army fled and Cao Xiu was able to make his escape back to Wei

text: A barred irregular galaxy is an irregular version of a barred spiral galaxy. Examples include the Large Magellanic Cloud and NGC 6822. Some barred irregular galaxies (like the Large Magellanic Cloud) may be dwarf spiral galaxies, which have been distorted into an irregular shape by tidal interactions with a more massive neighbor.

text: A barred irregular galaxy is an

text: irregular

text: version of a

text: barred spiral galaxy

text: . Examples include the

text: Large Magellanic Cloud

text: and

text: NGC 6822

text: . Some barred irregular galaxies (like the Large Magellanic Cloud) may be

text: dwarf spiral galaxies

text: , which have been distorted into an irregular shape by

text: tidal interactions

text: with a more massive neighbor.

text: In some nations, Muslim ethnic groups enjoy considerable autonomy.

text: In some nations, Muslim ethnic groups enjoy considerable

text: autonomy

text: There are many dwarf galaxies in the Local Group; these small galaxies frequently orbit larger galaxies, such as the Milky Way, the Andromeda Galaxy and the Triangulum Galaxy. A 2007 paper has suggested that many dwarf galaxies were created by galactic tide

text: There are many dwarf galaxies in the

text: Local Group

text: ; these small galaxies frequently orbit larger galaxies, such as the

text: Milky Way

text: , the

text: Andromeda Galaxy

text: and the

text: Triangulum Galaxy

text: . A 2007 paper has suggested that many dwarf galaxies were created by

text: galactic tide

text: Wynfrid Lawrence Henry Duckworth (5 June 1870 – 14 February 1956) was a British anatomist, and former Master of Jesus College, Cambridge. The Duckworth Laboratory (Department of Biological Anthropology) at Cambridge University is named after him.

text: In September 2015, Torres received a four-match ban from the Confederation of African Football for abusing a referee during the 2017 Africa Cup of Nations qualification game against Zambia three months earlier. He was sacked in March of the following year, after a 1–3 loss to Liberia.

text: In September 2015, Torres received a four-match ban from the

text: Confederation of African Football

text: for abusing a referee during the

entity_name: 2017 Africa Cup of Nations qualification

text: 2017 Africa Cup of Nations qualification

text: game against

text: Zambia

text: three months earlier. He was sacked in March of the following year, after a 1–3 loss to

text: Liberia

text: The soundtrack for the film was composed by Shyam.Oru Madhura Kinavin was a trend setting song especially for youths and was a huge hit. Its remixed and used in Pritviraj's movie Teja Bhai and Family (2011) and sung by Vijay Yesudas was also a hit.

text: The soundtrack for the film was composed by

text: Shyam

text: .Oru Madhura Kinavin was a trend setting song especially for youths and was a huge hit. Its remixed and used in Pritviraj's movie

text: Teja Bhai and Family

text: (2011) and sung by Vijay Yesudas was also a hit.

text: Chat rooms, particularly those intended for children, usually have rules that they require users to follow. The rules are generally posted before entry, either on a web page or an MOTD-type banner in the case of IRC and other text-based chat systems. Rules usually do not allow users to use offensive/rude language, or to promote hate, violence, and other negative issues. Many also disallow impersonating another user. Chat rooms often do not allow advertising or "flooding", which is continually filling the screen with repetitive text. Typing with caps lock on is usually considered shouting (suggesting anger) and is discouraged. Offenders of these rules can be "kicked" (temporarily ejected from the room, but allowed back in) or banned completely either on a temporary or permanent basis.

text: Chat rooms, particularly those intended for children, usually have rules that they require users to follow. The rules are generally posted before entry, either on a

text: web page

text: or an

text: MOTD

text: -type banner in the case of IRC and other text-based chat systems. Rules usually do not allow users to use offensive/rude language, or to promote hate, violence, and other negative issues. Many also disallow impersonating another user. Chat rooms often do not allow advertising or "flooding", which is continually filling the screen with repetitive text. Typing with

text: caps lock

text: on is usually considered shouting (suggesting anger) and is discouraged. Offenders of these rules can be "kicked" (temporarily ejected from the room, but allowed back in) or banned completely either on a temporary or permanent basis.

text: The Călugărul River is a tributary of the Conțeasca River in Romania.

text: The Călugărul River is a

text: tributary

text: of the

text: Conțeasca River

text: in

text: Romania

text: The rotating disc of a spiral galaxy, consisting of stars and solar systems, may become unstable in a way that the stars in the outer parts of the "arms" are released from the galaxy system, resulting in the collapse of the remaining stars into a bar-shaped galaxy. This occurs in approximately 1/3 of the known spiral galaxies.

text: Public celebrations of Carnival waned in the 19th century after Mexico’s independence and later Liberal movements discouraged it as an element of the country’s colonial past. From the late 19th century to the early 20th, the festival as a major public event has made something of a comeback in areas such as Veracruz, northwestern Mexico and the Yucatán Peninsula. The large scale celebrations have mostly become divorced from their religious roots with commercialization in the latter 20th century. However, the numerous smaller celebrations in rural areas have maintained indigenous and religious elements, making its manifestation varied depending on which indigenous cultures the celebration melded.

text: Public celebrations of Carnival waned in the 19th century after

text: Mexico’s independence

text: and later

text: Liberal movements

text: discouraged it as an element of the country’s colonial past. From the late 19th century to the early 20th, the festival as a major public event has made something of a comeback in areas such as

text: Veracruz

text: , northwestern Mexico and the Yucatán Peninsula. The large scale celebrations have mostly become divorced from their religious roots with commercialization in the latter 20th century. However, the numerous smaller celebrations in rural areas have maintained indigenous and religious elements, making its manifestation varied depending on which indigenous cultures the celebration melded.

text: Returning to Holy Spirit University of Kaslik, he obtained a Ph.D. in Philosophy of Education in 2001. Madi was also director in High School for five years and Supervisor of Studies for 10 years; he is also student of Dialogue among Religions, especially among Christian and Islamic religions.

text: Returning to

text: Holy Spirit University of Kaslik

text: , he obtained a Ph.D. in Philosophy of Education in 2001. Madi was also director in High School for five years and Supervisor of Studies for 10 years; he is also student of Dialogue among Religions, especially among Christian and Islamic religions.

text: Matter, dark matter, and dark energy are distributed homogeneously throughout the Universe over length scales longer than 300 million light-years or so. However, over shorter length-scales, matter tends to clump hierarchically; many atoms are condensed into stars, most stars into galaxies, most galaxies into clusters, superclusters and, finally, large-scale galactic filaments. The observable Universe contains approximately 300 sextillion (3) stars and more than 100 billion (10) galaxies. Typical galaxies range from dwarfs with as few as ten million (10) stars up to giants with one trillion (10) stars.  Between the structures are voids, which are typically 10–150 Mpc (33 million–490 million ly) in diameter. The Milky Way is in the Local Group of galaxies, which in turn is in the Laniakea Supercluster. This supercluster spans over 500 million light years, while the Local Group spans over 10 million light years. The Universe also has vast regions of relative emptiness; the largest known void measures 1.8 billion ly (550 Mpc) across.

text: Matter, dark matter, and dark energy are distributed homogeneously throughout the Universe over length scales longer than 300 million light-years or so. However, over shorter length-scales, matter tends to clump hierarchically; many

text: atom

text: s are condensed into

text: star

text: s, most stars into galaxies, most galaxies into

text: clusters, superclusters

text: and, finally, large-scale

text: galactic filaments

text: . The observable Universe contains approximately 300 sextillion (3) stars and more than 100 billion (10)

text: galaxies

text: . Typical galaxies range from

text: dwarfs

text: with as few as ten million (10) stars up to giants with one

text: trillion

text: (10) stars.  Between the structures are

text: void

text: s, which are typically 10–150 Mpc (33 million–490 million ly) in diameter. The

text: Milky Way

text: is in the

text: Local Group

text: of galaxies, which in turn is in the

text: Laniakea Supercluster

text: . This supercluster spans over 500 million light years, while the Local Group spans over 10 million light years. The Universe also has vast regions of relative emptiness; the largest known void measures 1.8 billion ly (550 Mpc) across.

text: would be to compute the exact values of

text: would be to compute the exact values of

text: It has been suggested that the HVSs in the Milky Way are a result of the passage of an orbiting dwarf galaxy near  the Milky Way. When the dwarf galaxy made its closest approach to the center of the Milky Way, it underwent intense gravitational tugs. These tugs boosted the energy of some of its stars so much that they broke free of the dwarf galaxy entirely and were thrown into space, due to the slingshot-like effect of the boost.

text: It has been suggested that the HVSs in the Milky Way are a result of the passage of an orbiting

text: dwarf galaxy

text: near  the Milky Way. When the dwarf galaxy made its closest approach to the center of the Milky Way, it underwent intense gravitational tugs. These tugs boosted the energy of some of its stars so much that they broke free of the dwarf galaxy entirely and were thrown into space, due to the slingshot-like effect of the boost.

text: The village gets its name from the Chechi clan of the Gujjar tribe.The village was founded approximately 800 years ago by the Chechi family ; who traditionally have been the tribal leaders & farmers of the region.The tribal leaders also referred to  as "Mehr" are those who belong to the chechi dynasty as the tittle is passed down father to son or by anointment. [Currently "Mehr Mohammed Riaz" son of late "Mehr Mohammed Hyatt"]

text: The village gets its name from the Chechi clan of the

text: Gujjar

text: tribe.The village was founded approximately 800 years ago by the Chechi family ; who traditionally have been the tribal leaders & farmers of the region.The tribal leaders also referred to  as "Mehr" are those who belong to the chechi dynasty as the tittle is passed down father to son or by anointment. [Currently "Mehr Mohammed Riaz" son of late "Mehr Mohammed Hyatt"]

text: A medical example is the likelihood that a given test result would be expected in a patient with a certain disorder compared to the likelihood that same result would occur in a patient without the target disorder.

text: More recent (and more radically shaped) innovations have addressed the ergonomic problems associated with playing the viola by making it shorter and lighter, while finding ways to keep the traditional sound. These include the Otto Erdesz "cutaway" viola, which has one shoulder cut out to make shifting easier; the "Oak Leaf" viola, which has two extra bouts; viol-shaped violas such as Joseph Curtin's "Evia" model, which also utilizes a moveable neck and a maple-veneered carbon fibre back, to reduce weight: violas played in the same manner as cellos (see vertical viola); and the eye-catching "Dalí-esque" shapes of both Bernard Sabatier's violas in fractional sizes—which appear to have melted—and David Rivinus' Pellegrina model violas.

text: More recent (and more radically shaped) innovations have addressed the ergonomic problems associated with playing the viola by making it shorter and lighter, while finding ways to keep the traditional sound. These include the Otto Erdesz "cutaway" viola, which has one shoulder cut out to make shifting easier; the "Oak Leaf" viola, which has two extra bouts;

text: viol

text: -shaped violas such as Joseph Curtin's "Evia" model, which also utilizes a moveable neck and a maple-veneered

text: carbon fibre

text: back, to reduce weight: violas played in the same manner as cellos (see

text: vertical viola

text: ); and the eye-catching

text: "Dalí

text: -esque" shapes of both Bernard Sabatier's violas in fractional sizes—which appear to have melted—and David Rivinus' Pellegrina model violas.

text: The Galaxy Line is about to return to Earth after 25 years running in space when it is attacked by a Cryner piloted by Count Nair. Lady, the Galaxy Line conductor, falls on Earth only with the Lion Ressha, while the other Safari Ressha that compose the Galaxy Line go missing, but she is rescued by the ToQgers. While Count Nair pays a visit to Emperor Z at the Castle Terminal, Right makes a plan to impulse the Lion Ressha back into space by using a local tower as part of a bridge, but Lady points out that there is not enough Imagination on Earth to power it up, claiming that with the decline of space exploration, people stopped aiming at the stars like they used to 50 years ago when the Galaxy Line was established.