Question 1

The Milky Way Galaxy is a(n) __________ galaxy.

Accepted Answer

A)  irregular 
B)  elliptical 
C)  nonbarred spiral 
D)  barred spiral 
E)  lenticular 
A)  irregular 
B)  elliptical 
C)  nonbarred spiral 
D)  barred spiral 
E)  lenticular D

Question 2

Magnetic fields in the Milky Way are concentrated in the disk because:

Accepted Answer

A)  halo stars are incapable of producing strong magnetic fields 
B)  the fields are tied to the charged particles in dense molecular clouds 
C)  gravity forces them to sink to the center of the disk 
D)  supernovae explosions continually force them toward the middle of the disk 
E)  supernovae explosions eliminate magnetic fields away from the disk 
A)  halo stars are incapable of producing strong magnetic fields 
B)  the fields are tied to the charged particles in dense molecular clouds 
C)  gravity forces them to sink to the center of the disk 
D)  supernovae explosions continually force them toward the middle of the disk 
E)  supernovae explosions eliminate magnetic fields away from the disk B

Question 3

In the Milky Way's outermost halo, the stars orbit:

Accepted Answer

A)  mostly in the prograde direction 
B)  mostly in the retrograde direction 
C)  both in the prograde and retrograde directions 
D)  the same way the disk stars do 
E)  neither in the prograde nor the retrograde directions 
A)  mostly in the prograde direction 
B)  mostly in the retrograde direction 
C)  both in the prograde and retrograde directions 
D)  the same way the disk stars do 
E)  neither in the prograde nor the retrograde directions C

Question 4

What objects are used to determine that the galaxy is mostly dark matter?

Accepted Answer

The presence of dark matter is indicated

Question 5

Our galaxy is __________ other galaxies because the dark matter in the Milky Way __________.

Accepted Answer

A)  unlike; makes up a small fraction of the total mass than in other galaxies 
B)  unlike; makes up a larger fraction of the total mass than in other galaxies 
C)  like; contains most of the mass in the galaxy 
D)  like; is made up of black holes and other stellar remnants 
E)  like; is made up of dust and faint objects of planetary mass 
A)  unlike; makes up a small fraction of the total mass than in other galaxies 
B)  unlike; makes up a larger fraction of the total mass than in other galaxies 
C)  like; contains most of the mass in the galaxy 
D)  like; is made up of black holes and other stellar remnants 
E)  like; is made up of dust and faint objects of planetary mass

Question 6

Explain how a standard candle allows you to determine the distance to an object. What is it that you have to measure or know about the standard candle to derive its distance?

Accepted Answer

A standard candle is a star that can be

Question 7

The Milky Way appears as __________ in the night sky because __________.

Accepted Answer

A)  randomly distributed stars; the Sun lies near the center of the Milky Way 
B)  a faint band of light sprinkled with dark clouds; the Sun lies in the disk 
C)  a faint band of light; the Sun lies in the halo 
D)  an ellipse of light in the Southern sky; the Sun lies midway along the disk 
E)  a circular disk with spiral arms; the Sun lies far above the galaxy's plane 
A)  randomly distributed stars; the Sun lies near the center of the Milky Way 
B)  a faint band of light sprinkled with dark clouds; the Sun lies in the disk 
C)  a faint band of light; the Sun lies in the halo 
D)  an ellipse of light in the Southern sky; the Sun lies midway along the disk 
E)  a circular disk with spiral arms; the Sun lies far above the galaxy's plane

Question 8

The locations of globular clusters on the sky and their distances tell us that the Sun is located near the center of the Milky Way.

Accepted Answer

A) True 
 B)False

Question 9

Why is 21-cm radiation the best way to map the spiral arms in the Milky Way?

Accepted Answer

A)  The molecular hydrogen gas that produces this emission is concentrated in the spiral arms. 
B)  These photons, which are produced by neutral hydrogen, pass through the dense clouds of gas and dust in the disk. 
C)  The emission is produced by supernovae, which are concentrated in the spiral arms. 
D)  Radio telescopes are easier to operate than optical telescopes, and observations can be made even during the daytime. 
E)  Radio photons do not have Doppler shifts, so we can detect clouds of gas without having to worry about the orbital velocities. 
A)  The molecular hydrogen gas that produces this emission is concentrated in the spiral arms. 
B)  These photons, which are produced by neutral hydrogen, pass through the dense clouds of gas and dust in the disk. 
C)  The emission is produced by supernovae, which are concentrated in the spiral arms. 
D)  Radio telescopes are easier to operate than optical telescopes, and observations can be made even during the daytime. 
E)  Radio photons do not have Doppler shifts, so we can detect clouds of gas without having to worry about the orbital velocities.

Question 10

In which part of the Milky Way would you find little or no neutral hydrogen, no current star formation, and stars that are all older than 10 billion years?

Accepted Answer

A)  the inner disk 
B)  the outer disk 
C)  the galactic center 
D)  the solar neighborhood 
E)  the halo 
A)  the inner disk 
B)  the outer disk 
C)  the galactic center 
D)  the solar neighborhood 
E)  the halo

Question 11

The oldest stars in the galaxy are usually __________ in heavy elements because __________.

Accepted Answer

A)  low; they have had time to accrete unprocessed gas from the interstellar medium 
B)  low; they were formed before much chemical enrichment had taken place 
C)  low; old stars must have low mass, and low-mass stars do not generate many heavy elements 
D)  high; they have turned a lot of their initial hydrogen and helium into heavier elements 
E)  high; stars with higher fractions of heavy elements have shorter lifetimes 
A)  low; they have had time to accrete unprocessed gas from the interstellar medium 
B)  low; they were formed before much chemical enrichment had taken place 
C)  low; old stars must have low mass, and low-mass stars do not generate many heavy elements 
D)  high; they have turned a lot of their initial hydrogen and helium into heavier elements 
E)  high; stars with higher fractions of heavy elements have shorter lifetimes

Question 12

There are many more individual stars residing in the Milky Way stellar halo than inside globular clusters.

Accepted Answer

A) True 
 B)False

Question 13

What type of standard candle is used to determine distances to globular clusters?

Accepted Answer

A)  O-type main-sequence stars 
B)  Cepheid variable stars 
C)  T Tauri stars 
D)  Type I supernovae 
E)  RR Lyrae stars 
A)  O-type main-sequence stars 
B)  Cepheid variable stars 
C)  T Tauri stars 
D)  Type I supernovae 
E)  RR Lyrae stars

Question 14

The Milky Way has both a thin and thick disk of stars. Which one of the following statements about them is FALSE?

Accepted Answer

A)  The thin disk stars on average are younger than the thick disk stars. 
B)  Molecular clouds are distributed more like the thin disk stars rather than the thick disk stars. 
C)  The thin disk stars on average have lower abundances of heavy elements than the thick disk stars. 
D)  The thick disk stars may be older thin disk stars that have higher upward velocities because they have gravitationally interacted more with molecular clouds in the spiral arms. 
E)  The thick disk may have formed when a small dwarf galaxy merged with the Milky Way. 
A)  The thin disk stars on average are younger than the thick disk stars. 
B)  Molecular clouds are distributed more like the thin disk stars rather than the thick disk stars. 
C)  The thin disk stars on average have lower abundances of heavy elements than the thick disk stars. 
D)  The thick disk stars may be older thin disk stars that have higher upward velocities because they have gravitationally interacted more with molecular clouds in the spiral arms. 
E)  The thick disk may have formed when a small dwarf galaxy merged with the Milky Way.

Question 15

If RR Lyrae stars in a globular cluster had an apparent magnitude of 11.5 and an absolute magnitude of 0.5, what would the globular cluster's distance be?

Accepted Answer

A)  1,600 pc 
B)  1,900 pc 
C)  2,500 pc 
D)  3,200 pc 
E)  8,600 pc 
A)  1,600 pc 
B)  1,900 pc 
C)  2,500 pc 
D)  3,200 pc 
E)  8,600 pc

Question 16

Why do we know that at least one generation of stars formed and died before the Milky Way's globular clusters formed?

Accepted Answer

A)  All globular cluster stars have some amount of heavy elements. 
B)  They are so old that nuclear fusion in globular cluster stars has altered their chemical abundances. 
C)  Globular clusters are 9 to 10 billion years old. 
D)  No globular cluster is older than 12 billion years. 
E)  All globular clusters reside in the disk of the Milky Way. 
A)  All globular cluster stars have some amount of heavy elements. 
B)  They are so old that nuclear fusion in globular cluster stars has altered their chemical abundances. 
C)  Globular clusters are 9 to 10 billion years old. 
D)  No globular cluster is older than 12 billion years. 
E)  All globular clusters reside in the disk of the Milky Way.

Question 17

You measure the chemical abundances and space motions of stars near the Sun, and plot your data in the figure shown below. The stars separate into two distinct groups, which you label A and B. These groups are, respectively, in which two stellar components of the Milky Way?

Accepted Answer

A)  disk and halo 
B)  bulge and disk 
C)  halo and disk 
D)  halo and bulge 
E)  globular clusters and halo 
A)  disk and halo 
B)  bulge and disk 
C)  halo and disk 
D)  halo and bulge 
E)  globular clusters and halo

Question 18

If the central black hole started accreting a lot of gas, it would appear as what kind of an object?

Accepted Answer

A)  a red supergiant 
B)  a pulsar 
C)  a planetary nebula 
D)  an AGN 
E)  a supernova remnant 
A)  a red supergiant 
B)  a pulsar 
C)  a planetary nebula 
D)  an AGN 
E)  a supernova remnant

Question 19

What observed property of the Milky Way suggests that it contains a large amount of matter not in the form of stars?

Accepted Answer

A)  the rotation curve 
B)  the velocities of the open star clusters 
C)  the number and shape of the spiral arms 
D)  the thickness of the disk 
E)  the presence of a black hole at the galactic center 
A)  the rotation curve 
B)  the velocities of the open star clusters 
C)  the number and shape of the spiral arms 
D)  the thickness of the disk 
E)  the presence of a black hole at the galactic center

Question 20

Where are the most metal-rich stars found in the Milky Way?

Accepted Answer

A)  in the disk near the Sun 
B)  near the center 
C)  in the halo 
D)  in globular clusters 
E)  in old open clusters 
A)  in the disk near the Sun 
B)  near the center 
C)  in the halo 
D)  in globular clusters 
E)  in old open clusters

Exam 21: The Milky Waya Normal Spiral Galaxy

The Milky Way Galaxy is a(n) __________ galaxy.

Magnetic fields in the Milky Way are concentrated in the disk because:

In the Milky Way's outermost halo, the stars orbit:

What objects are used to determine that the galaxy is mostly dark matter?

Our galaxy is __________ other galaxies because the dark matter in the Milky Way __________.

Explain how a standard candle allows you to determine the distance to an object. What is it that you have to measure or know about the standard candle to derive its distance?

The Milky Way appears as __________ in the night sky because __________.

The locations of globular clusters on the sky and their distances tell us that the Sun is located near the center of the Milky Way.

Why is 21-cm radiation the best way to map the spiral arms in the Milky Way?

In which part of the Milky Way would you find little or no neutral hydrogen, no current star formation, and stars that are all older than 10 billion years?

The oldest stars in the galaxy are usually __________ in heavy elements because __________.

There are many more individual stars residing in the Milky Way stellar halo than inside globular clusters.

What type of standard candle is used to determine distances to globular clusters?

The Milky Way has both a thin and thick disk of stars. Which one of the following statements about them is FALSE?

If RR Lyrae stars in a globular cluster had an apparent magnitude of 11.5 and an absolute magnitude of 0.5, what would the globular cluster's distance be?

Why do we know that at least one generation of stars formed and died before the Milky Way's globular clusters formed?

You measure the chemical abundances and space motions of stars near the Sun, and plot your data in the figure shown below. The stars separate into two distinct groups, which you label A and B. These groups are, respectively, in which two stellar components of the Milky Way?

If the central black hole started accreting a lot of gas, it would appear as what kind of an object?

What observed property of the Milky Way suggests that it contains a large amount of matter not in the form of stars?

Where are the most metal-rich stars found in the Milky Way?

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

The Expanding Universe

Galaxies

Modern Cosmology

Large-Scale Structure in the Universe

Life

Filters

Our galaxy is other galaxies because the dark matter in the Milky Way .

The Milky Way appears as in the night sky because .

The oldest stars in the galaxy are usually in heavy elements because .