Question 1

Why is it surprising to find spiral arms in spiral galaxies?

Accepted Answer

A)  Spiral arms require new stars, and previous new stars should have already used up the interstellar medium; no new stars should be forming now. 
B)  The variations in speed of the stars across galaxies are not high enough to twist the shape of the arms into a spiral. 
C)  There is no known mechanism to generate spiral arms. 
D)  The motions of the stars and differential rotation of the galaxy should have wound their arms tightly and made them blend and disappear. 
A)  Spiral arms require new stars, and previous new stars should have already used up the interstellar medium; no new stars should be forming now. 
B)  The variations in speed of the stars across galaxies are not high enough to twist the shape of the arms into a spiral. 
C)  There is no known mechanism to generate spiral arms. 
D)  The motions of the stars and differential rotation of the galaxy should have wound their arms tightly and made them blend and disappear.

Question 2

What is a lenticular (or S0) galaxy?

Accepted Answer

A)  galaxy with a central bulge and a disk like a spiral galaxy but with no spiral arms 
B)  galaxy with a smooth brightness profile and lacking the central bulge and disk of a spiral galaxy 
C)  galaxy with a lot of gas and dust and no particular structure 
D)  spiral galaxy with fuzzy and poorly formed spiral arms 
A)  galaxy with a central bulge and a disk like a spiral galaxy but with no spiral arms 
B)  galaxy with a smooth brightness profile and lacking the central bulge and disk of a spiral galaxy 
C)  galaxy with a lot of gas and dust and no particular structure 
D)  spiral galaxy with fuzzy and poorly formed spiral arms

Question 3

How do galaxies evolve on the Hubble tuning-fork classification scheme and what is the evolutionary significance of this diagram, shown in Figure 17-15 of the text?

Accepted Answer

A)  About three-quarters of galaxies do not evolve, but others can change their position. Usually, spiral galaxies merge to form ellipticals. 
B)  The "young" irregular and lenticular galaxies in the center of the tuning fork evolve to either elliptical galaxies if the material is metal-poor or spiral galaxies if the material is metal-rich. 
C)  Stars slowly die and the spiral arms slowly spin up and tighten to transform spiral galaxies into elliptical galaxies. 
D)  Elliptical galaxies slowly condense and spin up to form spiral galaxies, the increasing stellar collisions forming the interstellar material in the spiral arms. 
A)  About three-quarters of galaxies do not evolve, but others can change their position. Usually, spiral galaxies merge to form ellipticals. 
B)  The "young" irregular and lenticular galaxies in the center of the tuning fork evolve to either elliptical galaxies if the material is metal-poor or spiral galaxies if the material is metal-rich. 
C)  Stars slowly die and the spiral arms slowly spin up and tighten to transform spiral galaxies into elliptical galaxies. 
D)  Elliptical galaxies slowly condense and spin up to form spiral galaxies, the increasing stellar collisions forming the interstellar material in the spiral arms.

Question 4

Which of these is NOT a possible consequence of the interaction of two or more galaxies?

Accepted Answer

A)  Change of galaxy type. For example, two disk galaxies might merge to form an elliptical. 
B)  Globular clusters can form. 
C)  The black holes in one or more galaxies dissipate and enhance the intergalactic medium. 
D)  Gas can be liberated from the galaxies into the intergalactic medium. 
A)  Change of galaxy type. For example, two disk galaxies might merge to form an elliptical. 
B)  Globular clusters can form. 
C)  The black holes in one or more galaxies dissipate and enhance the intergalactic medium. 
D)  Gas can be liberated from the galaxies into the intergalactic medium.

Question 5

The Local Group is

Accepted Answer

A)  the name of the spiral arm of the Milky Way Galaxy in which the Sun is located. 
B)  a poor cluster of galaxies in which the Milky Way is located. 
C)  the family of planets around the Sun. 
D)  a star cluster to which the Sun belongs. 
A)  the name of the spiral arm of the Milky Way Galaxy in which the Sun is located. 
B)  a poor cluster of galaxies in which the Milky Way is located. 
C)  the family of planets around the Sun. 
D)  a star cluster to which the Sun belongs.

Question 6

A close encounter between two galaxies is LEAST likely to trigger starburst in which type of galaxy?

Accepted Answer

A)  ellipticals 
B)  barred spirals 
C)  normal spirals 
D)  irregulars 
A)  ellipticals 
B)  barred spirals 
C)  normal spirals 
D)  irregulars

Question 7

Who developed the classification system that divides galaxies into spiral, elliptical, and irregular and classifies spirals by the size of their nuclear region and the tightness of the winding of their arms?

Accepted Answer

A)  Ejnar Hertzsprung 
B)  Edwin Hubble 
C)  Sir John Herschel 
D)  Olaus Roemer 
A)  Ejnar Hertzsprung 
B)  Edwin Hubble 
C)  Sir John Herschel 
D)  Olaus Roemer

Question 8

What is an ultra-diffuse galaxy?

Accepted Answer

A)  a giant elliptical galaxy 
B)  a disk galaxy with no apparent spiral structure 
C)  a dwarf elliptical 
D)  a massive galaxy emitting only 1% as much light as the Milky Way 
A)  a giant elliptical galaxy 
B)  a disk galaxy with no apparent spiral structure 
C)  a dwarf elliptical 
D)  a massive galaxy emitting only 1% as much light as the Milky Way

Question 9

In which category of galaxy do astronomers find the largest galaxies in the universe?

Accepted Answer

A)  lenticular galaxies 
B)  large spiral galaxies like the Milky Way 
C)  irregular galaxies 
D)  elliptical galaxies 
A)  lenticular galaxies 
B)  large spiral galaxies like the Milky Way 
C)  irregular galaxies 
D)  elliptical galaxies

Question 10

Which of these speeds are described by Hubble's law?

Accepted Answer

A)  speeds of individual galaxies in the Local Group and other nearby galaxy clusters 
B)  speeds of superclusters of galaxies 
C)  speeds of stars in the Milky Way Galaxy 
D)  speeds of individual clusters of galaxies in the Milky Way's local supercluster 
A)  speeds of individual galaxies in the Local Group and other nearby galaxy clusters 
B)  speeds of superclusters of galaxies 
C)  speeds of stars in the Milky Way Galaxy 
D)  speeds of individual clusters of galaxies in the Milky Way's local supercluster

Question 11

What is the classification for a spiral galaxy with a small nuclear region and loosely wound arms?

Accepted Answer

A)  Sa 
B)  Sc 
C)  SBa 
D)  Sb 
A)  Sa 
B)  Sc 
C)  SBa 
D)  Sb

Question 12

Collisions between galaxies

Accepted Answer

A)  occur only very occasionally to produce spectacular supergalaxies containing many new stars. Only one or two examples have been detected so far. 
B)  are occurring all the time, all elliptical galaxies having resulted from such collisions. The collisions have cleared out all the gas and dust from these galaxies. 
C)  never happen since galaxies are so far apart in this universe. 
D)  can and do occur relatively frequently over cosmological times. 
A)  occur only very occasionally to produce spectacular supergalaxies containing many new stars. Only one or two examples have been detected so far. 
B)  are occurring all the time, all elliptical galaxies having resulted from such collisions. The collisions have cleared out all the gas and dust from these galaxies. 
C)  never happen since galaxies are so far apart in this universe. 
D)  can and do occur relatively frequently over cosmological times.

Question 13

If the elliptical galaxy in Boötes, shown near the bottom of Figure 17-32 of the text, were at a distance of 1.6 billion ly, what would be the value of Hubble's constant H0? (Be careful with units.)

Accepted Answer

A)  about 60 km/s per Mpc 
B)  about 25 km/s per Mpc 
C)  about 95 km/s per Mpc 
D)  about 80 km/s per Mpc 
A)  about 60 km/s per Mpc 
B)  about 25 km/s per Mpc 
C)  about 95 km/s per Mpc 
D)  about 80 km/s per Mpc

Question 14

The Hubble classification description for an S0 galaxy is a

Accepted Answer

A)  small central bulge with loosely wound spiral arms. 
B)  disk and central bulge with a smooth light distribution and no spiral arms. 
C)  large central bulge with tightly wound spiral arms. 
D)  round or spherical shape with a smooth light distribution and no disk or central bulge. 
A)  small central bulge with loosely wound spiral arms. 
B)  disk and central bulge with a smooth light distribution and no spiral arms. 
C)  large central bulge with tightly wound spiral arms. 
D)  round or spherical shape with a smooth light distribution and no disk or central bulge.

Question 15

Doppler measurements of the motions of stars in nearby spiral and barred galaxies indicate that

Accepted Answer

A)  in most spiral and barred galaxies, the arms trail behind the rotating nucleus. 
B)  in most spiral and barred galaxies, the arms rotate ahead of the nucleus; that is, spiral and barred galaxies are mostly leading-arm galaxies. 
C)  in most spiral and barred galaxies, the arms lead the rotation of the nucleus; that is, the arms spin faster than the nucleus. 
D)  about half of all galaxies have trailing arms-the stars rotate slower than the nucleus-while in the other half, the arms rotate ahead of the nucleus. 
A)  in most spiral and barred galaxies, the arms trail behind the rotating nucleus. 
B)  in most spiral and barred galaxies, the arms rotate ahead of the nucleus; that is, spiral and barred galaxies are mostly leading-arm galaxies. 
C)  in most spiral and barred galaxies, the arms lead the rotation of the nucleus; that is, the arms spin faster than the nucleus. 
D)  about half of all galaxies have trailing arms-the stars rotate slower than the nucleus-while in the other half, the arms rotate ahead of the nucleus.

Question 16

What is the galaxy content of rich, regular clusters like the Coma cluster?

Accepted Answer

A)  more or less even distribution of spirals, ellipticals, irregulars, and S0 galaxies 
B)  mostly ellipticals and S0 galaxies and relatively few spirals and irregulars 
C)  entirely elliptical galaxies 
D)  mostly spirals and irregulars with relatively few ellipticals and S0 galaxies 
A)  more or less even distribution of spirals, ellipticals, irregulars, and S0 galaxies 
B)  mostly ellipticals and S0 galaxies and relatively few spirals and irregulars 
C)  entirely elliptical galaxies 
D)  mostly spirals and irregulars with relatively few ellipticals and S0 galaxies

Question 17

A grand-design spiral of type SBa has all of these EXCEPT

Accepted Answer

A)  tightly wound spiral arms. 
B)  a central bar. 
C)  about 25% gas and dust. 
D)  a halo of globular clusters. 
A)  tightly wound spiral arms. 
B)  a central bar. 
C)  about 25% gas and dust. 
D)  a halo of globular clusters.

Question 18

What is the galaxy content of rich, irregular clusters of galaxies such as the Hercules cluster?

Accepted Answer

A)  about the same number of spirals as ellipticals 
B)  entirely spirals 
C)  more than one-half spirals, less than one-quarter ellipticals 
D)  more than one-half ellipticals, less than one-quarter spirals 
A)  about the same number of spirals as ellipticals 
B)  entirely spirals 
C)  more than one-half spirals, less than one-quarter ellipticals 
D)  more than one-half ellipticals, less than one-quarter spirals

Question 19

The Milky Way Galaxy and the Andromeda Galaxy (M31) will probably collide in about 4 billion years. What is the probable result?

Accepted Answer

A)  Both galaxies will disappear and become part of the intergalactic medium. 
B)  Most of the stars will dissipate into the intergalactic medium, but a smaller spiral galaxy will remain. 
C)  A giant elliptical will form. 
D)  An irregular galaxy will form. 
A)  Both galaxies will disappear and become part of the intergalactic medium. 
B)  Most of the stars will dissipate into the intergalactic medium, but a smaller spiral galaxy will remain. 
C)  A giant elliptical will form. 
D)  An irregular galaxy will form.

Question 20

Suppose the Milky Way Galaxy is 1 of a 1000 billion galaxies and they similarly have, on average, 200 billion stars each. How many stars is that?

Accepted Answer

A)  2 * 1019 
B)  2 *1021 
C)  2 *1023 
D)  2 * 1025 
A)  2 * 1019 
B)  2 *1021 
C)  2 *1023 
D)  2 * 1025

Why is it surprising to find spiral arms in spiral galaxies?

What is a lenticular (or S0) galaxy?

How do galaxies evolve on the Hubble tuning-fork classification scheme and what is the evolutionary significance of this diagram, shown in Figure 17-15 of the text?

Which of these is NOT a possible consequence of the interaction of two or more galaxies?

The Local Group is

A close encounter between two galaxies is LEAST likely to trigger starburst in which type of galaxy?

Who developed the classification system that divides galaxies into spiral, elliptical, and irregular and classifies spirals by the size of their nuclear region and the tightness of the winding of their arms?

What is an ultra-diffuse galaxy?

In which category of galaxy do astronomers find the largest galaxies in the universe?

Which of these speeds are described by Hubble's law?

What is the classification for a spiral galaxy with a small nuclear region and loosely wound arms?

Collisions between galaxies

If the elliptical galaxy in Boötes, shown near the bottom of Figure 17-32 of the text, were at a distance of 1.6 billion ly, what would be the value of Hubble's constant H₀? (Be careful with units.)

The Hubble classification description for an S0 galaxy is a

Doppler measurements of the motions of stars in nearby spiral and barred galaxies indicate that

What is the galaxy content of rich, regular clusters like the Coma cluster?

A grand-design spiral of type SBa has all of these EXCEPT

What is the galaxy content of rich, irregular clusters of galaxies such as the Hercules cluster?

The Milky Way Galaxy and the Andromeda Galaxy (M31) will probably collide in about 4 billion years. What is the probable result?

Suppose the Milky Way Galaxy is 1 of a 1000 billion galaxies and they similarly have, on average, 200 billion stars each. How many stars is that?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

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Exam 17: Galaxies

Why is it surprising to find spiral arms in spiral galaxies?

What is a lenticular (or S0) galaxy?

How do galaxies evolve on the Hubble tuning-fork classification scheme and what is the evolutionary significance of this diagram, shown in Figure 17-15 of the text?

Which of these is NOT a possible consequence of the interaction of two or more galaxies?

The Local Group is

A close encounter between two galaxies is LEAST likely to trigger starburst in which type of galaxy?

Who developed the classification system that divides galaxies into spiral, elliptical, and irregular and classifies spirals by the size of their nuclear region and the tightness of the winding of their arms?

What is an ultra-diffuse galaxy?

In which category of galaxy do astronomers find the largest galaxies in the universe?

Which of these speeds are described by Hubble's law?

What is the classification for a spiral galaxy with a small nuclear region and loosely wound arms?

Collisions between galaxies

If the elliptical galaxy in Boötes, shown near the bottom of Figure 17-32 of the text, were at a distance of 1.6 billion ly, what would be the value of Hubble's constant H0? (Be careful with units.)

The Hubble classification description for an S0 galaxy is a

Doppler measurements of the motions of stars in nearby spiral and barred galaxies indicate that

What is the galaxy content of rich, regular clusters like the Coma cluster?

A grand-design spiral of type SBa has all of these EXCEPT

What is the galaxy content of rich, irregular clusters of galaxies such as the Hercules cluster?

The Milky Way Galaxy and the Andromeda Galaxy (M31) will probably collide in about 4 billion years. What is the probable result?

Suppose the Milky Way Galaxy is 1 of a 1000 billion galaxies and they similarly have, on average, 200 billion stars each. How many stars is that?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters

If the elliptical galaxy in Boötes, shown near the bottom of Figure 17-32 of the text, were at a distance of 1.6 billion ly, what would be the value of Hubble's constant H₀? (Be careful with units.)