Question 1

Scientists have found many stars in the outer halo that ________ the rotation of the galactic disk and have a very ________ fraction of heavy elements.

Accepted Answer

A)  move in a direction opposite to; high 
B)  move in a direction opposite to; low 
C)  move in the same direction as; high 
D)  move in the same direction as; low 
E)  don't move at all with respect to; low 
A)  move in a direction opposite to; high 
B)  move in a direction opposite to; low 
C)  move in the same direction as; high 
D)  move in the same direction as; low 
E)  don't move at all with respect to; low

Question 2

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

Accepted Answer

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

Question 3

The extended hot "halo" of gas surrounding our galaxy is thought to contain ________ mass as the sum of the Milky Way's stellar mass.

Accepted Answer

A)  the same amount of 
B)  1/10 as much 
C)  10 times as much 
D)  1/1,000 as much 
E)  1,000 times as much 
A)  the same amount of 
B)  1/10 as much 
C)  10 times as much 
D)  1/1,000 as much 
E)  1,000 times as much

Question 4

You measure the heavy element abundances and motions of stars near the Sun.When plotting your data, you find that the stars separate into two distinct groups, which you label A and B.Group A has velocities and heavy-element abundances similar to the Sun's, while Group B has high velocities and low heavy-element abundances.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 5

Which of the following statements about the galactic magnetic fields is true?

Accepted Answer

A)  Cosmic rays spiraling magnetic fields produce the radio "glow" of the galactic disk. 
B)  They are confined mostly to the galactic disk. 
C)  They trap cosmic rays and interact with them. 
D)  They are anchored in molecular clouds. 
E)  All of these are true. 
A)  Cosmic rays spiraling magnetic fields produce the radio "glow" of the galactic disk. 
B)  They are confined mostly to the galactic disk. 
C)  They trap cosmic rays and interact with them. 
D)  They are anchored in molecular clouds. 
E)  All of these are true.

Question 6

Astronomers have identified examples of extraordinarily massive globular clusters (in both the Milky Way and Andromeda) that contain several million solar masses worth of stars.Moreover, these clusters also show evidence of multiple stellar populations.What would be a reasonable interpretation for such atypical clusters?

Accepted Answer

Such supermassive globular clusters that

Question 7

Which objects in our Milky Way Galaxy have orbits that are similar to the orbits of stars in elliptical galaxies?

Accepted Answer

A)  molecular clouds 
B)  halo stars 
C)  thin disk stars 
D)  thick disk stars 
E)  open clusters 
A)  molecular clouds 
B)  halo stars 
C)  thin disk stars 
D)  thick disk stars 
E)  open clusters

Question 8

Where in the Milky Way would we find the stars with the highest abundance of massive elements? Where would we find those with the lowest abundance of massive elements? Why?

Accepted Answer

Stars with the highest abundance of mass

Question 9

The figure shown below immediately reveals that

Accepted Answer

A)  disk material concentrates along the spiral arms but is completely absent between the arms. 
B)  spiral arms are sites where ongoing star formation happens efficiently. 
C)  disk galaxies do not contain any red, old stars. 
D)  the space between spiral arms must be filled with thick layers of invisible dark matter. 
E)  star formation happens only in the spiral arms of galaxies without bars. 
A)  disk material concentrates along the spiral arms but is completely absent between the arms. 
B)  spiral arms are sites where ongoing star formation happens efficiently. 
C)  disk galaxies do not contain any red, old stars. 
D)  the space between spiral arms must be filled with thick layers of invisible dark matter. 
E)  star formation happens only in the spiral arms of galaxies without bars.

Question 10

Why is the supermassive black hole in the center of our galaxy not an AGN right now? Could it be active in the future? Why or why not?

Accepted Answer

It is not an AGN (active galactic nucleu

Question 11

The highest-energy cosmic rays that reach Earth

Accepted Answer

A)  could actually originate outside the Milky Way Galaxy. 
B)  are produced in particle accelerators here on Earth. 
C)  emerge from the supermassive black hole at the center of the Milky Way. 
D)  are in fact X-ray and gamma-ray photons. 
E)  are the best candidates for explaining dark matter. 
A)  could actually originate outside the Milky Way Galaxy. 
B)  are produced in particle accelerators here on Earth. 
C)  emerge from the supermassive black hole at the center of the Milky Way. 
D)  are in fact X-ray and gamma-ray photons. 
E)  are the best candidates for explaining dark matter.

Question 12

The most distant galaxy observable with the naked eye from Earth is the

Accepted Answer

A)  Large Magellanic Cloud. 
B)  Sombrero Galaxy. 
C)  Sagittarius Dwarf. 
D)  Andromeda Galaxy. 
E)  Small Magellanic Cloud. 
A)  Large Magellanic Cloud. 
B)  Sombrero Galaxy. 
C)  Sagittarius Dwarf. 
D)  Andromeda Galaxy. 
E)  Small Magellanic Cloud.

Question 13

The presence of dwarf galaxies in orbit around the Milky Way supports what picture of our galaxy's formation?

Accepted Answer

A)  The galaxy formed through the merger of two large galaxies, which scattered their dwarf companions across large distances. 
B)  The galaxy originally formed with no dark matter but gained its dark matter through the absorption of smaller dwarf systems. 
C)  The galaxy formed in a giant explosion caused by the violent collisions of clouds of dark matter. 
D)  The galaxy formed a long time ago and has been passively evolving since. 
E)  The galaxy was formed by the merger of smaller protogalactic clumps. 
A)  The galaxy formed through the merger of two large galaxies, which scattered their dwarf companions across large distances. 
B)  The galaxy originally formed with no dark matter but gained its dark matter through the absorption of smaller dwarf systems. 
C)  The galaxy formed in a giant explosion caused by the violent collisions of clouds of dark matter. 
D)  The galaxy formed a long time ago and has been passively evolving since. 
E)  The galaxy was formed by the merger of smaller protogalactic clumps.

Question 14

Astronomers expect stars near the edge of the galactic disk to have smaller amounts of heavy elements than other parts of the disk because

Accepted Answer

A)  there is more star formation but fewer supernovae at the edge. 
B)  there is less star formation and fewer supernovae at the edge. 
C)  there is less star formation even though there are more supernovae at the edge. 
D)  there is more star formation and more supernovae at the edge. 
E)  None of these apply; there is no reason to expect the disk to be different based on location. 
A)  there is more star formation but fewer supernovae at the edge. 
B)  there is less star formation and fewer supernovae at the edge. 
C)  there is less star formation even though there are more supernovae at the edge. 
D)  there is more star formation and more supernovae at the edge. 
E)  None of these apply; there is no reason to expect the disk to be different based on location.

Question 15

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 elliptical patch 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 galactic 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 elliptical patch 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 galactic plane

Question 16

What are the major differences between globular and open star clusters?

Accepted Answer

Globular and open clusters differ in ter

Question 17

By comparing globular clusters, you find that Cluster A's RR Lyrae stars are 100 times fainter than Cluster B's RR Lyrae stars.You know that both clusters have approximately the same chemical composition and age, and thus their RR Lyrae stars should have the same luminosities.Which is true about the clusters' distances?

Accepted Answer

A)  Cluster A is 10 times farther away than Cluster B. 
B)  Cluster A is 10 times closer to us than Cluster B. 
C)  Clusters A and B are approximately the same distance from us. 
D)  Cluster A is 100 times farther away than Cluster B. 
E)  Cluster A is 100 times closer to us than Cluster B. 
A)  Cluster A is 10 times farther away than Cluster B. 
B)  Cluster A is 10 times closer to us than Cluster B. 
C)  Clusters A and B are approximately the same distance from us. 
D)  Cluster A is 100 times farther away than Cluster B. 
E)  Cluster A is 100 times closer to us than Cluster B.

Question 18

Measurements show that globular clusters contain very low amounts of heavy elements.How do scientists measure the ages of these clusters?

Accepted Answer

1)As we learned in a previous chapter,an

Question 19

Why do members of the Local Group violate Hubble's law? What property of nature allows them to do this?

Accepted Answer

The Local Group violates Hubble's Law be

Question 20

How have astronomers measured the mass of the black hole at the center of our galaxy?

Accepted Answer

A)  by using the rotation curve derived from 21-cm emission 
B)  by observing the motions of stars near the center of the galaxy 
C)  by measuring the brightness of the quasar 
D)  by measuring the Doppler shift of Sagittarius A* 
E)  by counting the number of supernova explosions near the black hole during the last century 
A)  by using the rotation curve derived from 21-cm emission 
B)  by observing the motions of stars near the center of the galaxy 
C)  by measuring the brightness of the quasar 
D)  by measuring the Doppler shift of Sagittarius A* 
E)  by counting the number of supernova explosions near the black hole during the last century

Exam 20: The Milky Waya Normal Spiral Galaxy

Scientists have found many stars in the outer halo that ________ the rotation of the galactic disk and have a very ________ fraction of heavy elements.

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

The extended hot "halo" of gas surrounding our galaxy is thought to contain ________ mass as the sum of the Milky Way's stellar mass.

Which of the following statements about the galactic magnetic fields is true?

Which objects in our Milky Way Galaxy have orbits that are similar to the orbits of stars in elliptical galaxies?

Where in the Milky Way would we find the stars with the highest abundance of massive elements? Where would we find those with the lowest abundance of massive elements? Why?

The figure shown below immediately reveals that

Why is the supermassive black hole in the center of our galaxy not an AGN right now? Could it be active in the future? Why or why not?

The highest-energy cosmic rays that reach Earth

The most distant galaxy observable with the naked eye from Earth is the

The presence of dwarf galaxies in orbit around the Milky Way supports what picture of our galaxy's formation?

Astronomers expect stars near the edge of the galactic disk to have smaller amounts of heavy elements than other parts of the disk because

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

What are the major differences between globular and open star clusters?

Measurements show that globular clusters contain very low amounts of heavy elements.How do scientists measure the ages of these clusters?

Why do members of the Local Group violate Hubble's law? What property of nature allows them to do this?

How have astronomers measured the mass of the black hole at the center of our galaxy?

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Formation of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Planetary Moons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

The Interstellar Medium and Star Formation

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

Galaxies

The Expanding Universe

Cosmology

Large-Scale Structure in the Universe

Life

Filters

Scientists have found many stars in the outer halo that the rotation of the galactic disk and have a very fraction of heavy elements.

The Milky Way appears as in the night sky because .