Question 1

If you want to look for old stars with low amounts of heavy elements, the best place to look out of the following locations is

Accepted Answer

A)   the galactic bulge.
B)   the central bar.
C)   the stellar halo.
D)   the thin disk.
E)   the thick disk.F) A) and E)
G) B) and C)

Question 2

Any single star in the Milky Way Galaxy has the same elemental abundances as

Accepted Answer

A)   all other stars in the Milky Way.
B)   all other stars in the galactic disk.
C)   the cloud of gas it formed from.
D)   all other stars of the same age.
E)   the stars nearest to it in space.F) B) and C)
G) B) and E)

Question 3

The gamma-ray bubbles at the poles of our galaxy are evidence that the nucleus of the Milky Way was once a(n)

Accepted Answer

A)   very high-mass star.
B)   pulsar.
C)   Herbig-Haro object.
D)   active galactic nucleus (AGN) .
E)   supernova.F) A) and B)
G) A) and C)

Question 4

Explain why within the galactic disk we can find older stars that have higher abundances of massive elements than younger stars at larger radii from the center.

Accepted Answer

The denser,inner part of the galactic di...

Question 5

The Large Magellanic Cloud is about 50 kpc from the center of the Milky Way and moves around it at about 170 km/s, as shown in the figure below.What is the inferred mass of the galaxy enclosed within this radial extent? 11 MSUN B)  9.4 * 1010 MSUN C)  2.0 * 1010 MSUN D)  3.1 * 1012 MSUN E)  1.7 * 107 MSUN" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   3.4 *1011 MSUN
B)   9.4 * 1010 MSUN
C)   2.0 * 1010 MSUN
D)   3.1 * 1012 MSUN
E)   1.7 * 107 MSUNF) A) and B)
G) A) and C)

Question 6

What is expected to happen to our Solar System when the Andromeda and Milky Way galaxies collide?

Accepted Answer

A)   The Sun is expected to collide with another star, destroying our Solar System.
B)   The Sun will be unaffected, but the planets will be scattered into space or destroyed.
C)   The Sun will have exploded by then, and Earth will already be uninhabitable.
D)   The Sun may be thrown to a different orbit within the merged galaxies, but the solar system will be relatively unchanged.
E)   The Sun may be thrown to a different orbit within the galaxies, and the planets will be scattered off into space.F) A) and E)
G) A) and D)

Question 7

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 from the halo.F) A) and B)
G) D) and E)

Question 8

Most of the mass in our galaxy is in the form of

Accepted Answer

A)   stars.
B)   gas.
C)   dust.
D)   dark matter.
E)   globular clusters.F) A) and B)
G) None of the above

Question 9

In a star that has heavy-element abundance similar to the Sun's, what percentage of the star's mass is made up of elements heavier than hydrogen and helium?

Accepted Answer

A)   0.1 percent
B)   0.2 percent
C)   2 percent
D)   10 percent
E)   20 percentF) None of the above
G) A) and E)

Question 10

By comparing globular clusters, you find that Cluster A's RR Lyrae stars are 225 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 cluster has the larger distance, and what is the ratio of the clusters' distances?

Accepted Answer

Distance is given by <img  loading="lazy" src="/assets/images/blured-textbook.svg" class="d-inline m-1" alt="blured image" width="139" height="30"> ,where L...

Question 11

What type of standard candles did Shapley use to determine distances to globular clusters?

Accepted Answer

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

Question 12

What observed property of the Milky Way suggests that it must contain a large amount of matter not in the form of stars, gas, or dust?

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 supermassive black hole at the galactic centerF) C) and D)
G) None of the above

Question 13

Andromeda and the Milky Way are approaching at a measured relative speed of 110 km/s.If Andromeda is currently separated from the Milky Way by about 770 kpc, provide a simple estimate for how far in the cosmic future the two galaxies will collide.Why is this estimate "simple," and not correct?

Accepted Answer

A simple estimate comes from d / v = 770...

Question 14

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 haloF) A) and E)
G) A) and B)

Question 15

The motion and chemical composition of stars in the outer halo may suggest that

Accepted Answer

A)   it had formed long ago as a product of merger with a small galaxy.
B)   it is very young and luminous.
C)   it is filled with cosmic rays.
D)   its composition is altered by galactic fountains.
E)   it does not contain any dark matter.F) C) and D)
G) B) and C)

Question 16

How would we explain why are there are no known disk stars with exceptionally low abundances of massive elements?

Accepted Answer

The gas that eventually assembled into t...

Question 17

Halo stars near the Sun are distinguished from disk stars by what characteristics?

Accepted Answer

A)   low heavy-element abundances and low relative velocities
B)   high heavy-element abundances and high relative velocities
C)   low heavy-element abundances and high relative velocities
D)   high heavy-element abundances and low relative velocities
E)   equal heavy-element abundances and high relative velocitiesF) A) and E)
G) A) and B)

Question 18

The "normal" mass of the Milky Way (stars and interstellar medium together) is estimated at 100 billion-200 billion solar masses.The total mass of the galaxy measured by its rotation curve, however, is estimated in the interval of 1 trillion-1.5 trillion solar masses.How do we explain this discrepancy? What fraction of the Milky Way's mass is "normal"?

Accepted Answer

The difference between the total and the...

Question 19

Why is it that, when astronomers look in the direction of the Sun's motion around the galaxy, that we see many stars that are blueshifted?

Accepted Answer

For stars to be blueshifted,they must be...

Question 20

In the figure below, we expect the absorption lines in the indicated star's spectrum to be

Accepted Answer

A)   normal/unchanged.
B)   redshifted.
C)   blueshifted.
D)   wider than usual.
E)   narrower than usual.F) C) and D)
G) A) and E)

Exam 20: The Milky Waya Normal Spiral Galaxy

Correct Answer
verified
The difference between the total and the...
View Answer

The Large Magellanic Cloud is about 50 kpc from the center of the Milky Way and moves around it at about 170 km/s, as shown in the figure below.What is the inferred mass of the galaxy enclosed within this radial extent?

Correct Answer
verified

In a star that has heavy-element abundance similar to the Sun's, what percentage of the star's mass is made up of elements heavier than hydrogen and helium?

Correct Answer
verified

Andromeda and the Milky Way are approaching at a measured relative speed of 110 km/s.If Andromeda is currently separated from the Milky Way by about 770 kpc, provide a simple estimate for how far in the cosmic future the two galaxies will collide.Why is this estimate "simple," and not correct?

Correct Answer
verified
A simple estimate comes from d / v = 770...
View Answer

Any single star in the Milky Way Galaxy has the same elemental abundances as

Correct Answer
verified

What is expected to happen to our Solar System when the Andromeda and Milky Way galaxies collide?

Correct Answer
verified

In the figure below, we expect the absorption lines in the indicated star's spectrum to be

Correct Answer
verified

The gamma-ray bubbles at the poles of our galaxy are evidence that the nucleus of the Milky Way was once a(n)

Correct Answer
verified

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

Correct Answer
verified

What type of standard candles did Shapley use to determine distances to globular clusters?

Correct Answer
verified

What observed property of the Milky Way suggests that it must contain a large amount of matter not in the form of stars, gas, or dust?

Correct Answer
verified

The motion and chemical composition of stars in the outer halo may suggest that

Correct Answer
verified

How would we explain why are there are no known disk stars with exceptionally low abundances of massive elements?

Correct Answer
verified
The gas that eventually assembled into t...
View Answer

Correct Answer
verified
Distance is given by ,where L...
View Answer

Why is it that, when astronomers look in the direction of the Sun's motion around the galaxy, that we see many stars that are blueshifted?

Correct Answer
verified
For stars to be blueshifted,they must be...
View Answer

Most of the mass in our galaxy is in the form of

Correct Answer
verified

Halo stars near the Sun are distinguished from disk stars by what characteristics?

Correct Answer
verified

If you want to look for old stars with low amounts of heavy elements, the best place to look out of the following locations is

Correct Answer
verified

Explain why within the galactic disk we can find older stars that have higher abundances of massive elements than younger stars at larger radii from the center.

Correct Answer
verified
The denser,inner part of the galactic di...
View Answer

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?

Correct Answer
verified

Exam 20: The Milky Waya Normal Spiral Galaxy

Correct AnswerverifiedThe difference between the total and the...View AnswerShow Answer

The Large Magellanic Cloud is about 50 kpc from the center of the Milky Way and moves around it at about 170 km/s, as shown in the figure below.What is the inferred mass of the galaxy enclosed within this radial extent?

Correct AnswerverifiedShow Answer

In a star that has heavy-element abundance similar to the Sun's, what percentage of the star's mass is made up of elements heavier than hydrogen and helium?

Correct AnswerverifiedShow Answer

Andromeda and the Milky Way are approaching at a measured relative speed of 110 km/s.If Andromeda is currently separated from the Milky Way by about 770 kpc, provide a simple estimate for how far in the cosmic future the two galaxies will collide.Why is this estimate "simple," and not correct?

Correct AnswerverifiedA simple estimate comes from d / v = 770...View AnswerShow Answer

Any single star in the Milky Way Galaxy has the same elemental abundances as

Correct AnswerverifiedShow Answer

What is expected to happen to our Solar System when the Andromeda and Milky Way galaxies collide?

Correct AnswerverifiedShow Answer

In the figure below, we expect the absorption lines in the indicated star's spectrum to be

Correct AnswerverifiedShow Answer

The gamma-ray bubbles at the poles of our galaxy are evidence that the nucleus of the Milky Way was once a(n)

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

What type of standard candles did Shapley use to determine distances to globular clusters?

Correct AnswerverifiedShow Answer

What observed property of the Milky Way suggests that it must contain a large amount of matter not in the form of stars, gas, or dust?

Correct AnswerverifiedShow Answer

The motion and chemical composition of stars in the outer halo may suggest that

Correct AnswerverifiedShow Answer

How would we explain why are there are no known disk stars with exceptionally low abundances of massive elements?

Correct AnswerverifiedThe gas that eventually assembled into t...View AnswerShow Answer

Correct AnswerverifiedDistance is given by ,where L...View AnswerShow Answer

Why is it that, when astronomers look in the direction of the Sun's motion around the galaxy, that we see many stars that are blueshifted?

Correct AnswerverifiedFor stars to be blueshifted,they must be...View AnswerShow Answer

Most of the mass in our galaxy is in the form of

Correct AnswerverifiedShow Answer

Halo stars near the Sun are distinguished from disk stars by what characteristics?

Correct AnswerverifiedShow Answer

If you want to look for old stars with low amounts of heavy elements, the best place to look out of the following locations is

Correct AnswerverifiedShow Answer

Explain why within the galactic disk we can find older stars that have higher abundances of massive elements than younger stars at larger radii from the center.

Correct AnswerverifiedThe denser,inner part of the galactic di...View AnswerShow Answer

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?

Correct AnswerverifiedShow Answer

Correct Answer
verified
The difference between the total and the...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
A simple estimate comes from d / v = 770...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The gas that eventually assembled into t...
View Answer

Correct Answer
verified
Distance is given by ,where L...
View Answer

Correct Answer
verified
For stars to be blueshifted,they must be...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The denser,inner part of the galactic di...
View Answer

Correct Answer
verified