Question 1

How many stars does an "average" galaxy like the Milky Way have?

Accepted Answer

A)   106
B)   109
C)   1011
D)   1013

Question 2

How do stars in the disk of the Milky Way move?

Accepted Answer

A)   on generally circular orbits in the same direction
B)   on generally circular orbits, in either direction
C)   on random orbits
D)   on oscillatory orbits, in either direction

Question 3

The figure below shows a spiral arm inside a galaxy.Relative to the spiral arm,in which direction (if any)are the gas and stars inside the galaxy moving?

Accepted Answer

From right...

Question 4

Where is the Sun located within the Milky Way?

Accepted Answer

A)   at the center of the bulge
B)   in the halo, about 1 kpc from the center
C)   in the disk, about 1 kpc from the center
D)   in the disk, about 8 kpc from the center

Question 5

Why do older stars tend to be at larger heights above the midplane of the Milky Way's disk?

Accepted Answer

A)   The Milky Way was thicker in the past.
B)   The halo's gravity has pulled them upward.
C)   They were born with large velocities in their molecular clouds.
D)   They have had many scattering encounters with other stars.

Question 6

During the formation of the Milky Way,why did the gas collapse to a disk while the stars remained in a spherical distribution?

Accepted Answer

Gas clouds collide w...

Question 7

Which of the following stars is most likely to have formed in a spiral arm?

Accepted Answer

A)   massive stars
B)   low-luminosity stars
C)   M stars
D)   all of the above

Question 8

How does the fraction of heavy elements inside gas clouds vary with location in the Milky Way's disk?

Accepted Answer

It decreases with di...

Question 9

Why is the metallicity of Population I stars greater than that of Population II stars?

Accepted Answer

Population I stars formed afte...

Question 10

The Magellanic Stream is evidence of:

Accepted Answer

A)   a collision of the Large and Small Magellanic Clouds.
B)   tidal stripping of the Magellanic Clouds by the Milky Way.
C)   gravitational interactions with Andromeda.
D)   continued gas accretion onto the Milky Way.

Question 11

How did Harlow Shapley avoid the bias of dust when measuring the size and shape of the Milky Way?

Accepted Answer

A)   by observing in the infrared
B)   by observing in the radio
C)   with star counts
D)   using globular clusters

Question 12

The figure below shows the rotation curve of a galaxy.How does the mass enclosed within a given distance from the galaxy's center vary?

Accepted Answer

A)   The mass is concentrated near the center.
B)   The enclosed mass increases linearly with distance.
C)   The enclosed mass increases with the square of distance.
D)   The enclosed mass increases like the square root of distance.

Question 13

An observer far from any city lights might see the feature shown in the figure below at night.What generates the diffuse light seen here?

Accepted Answer

Stars in t...

Question 14

The appearance of O and B stars in spiral arms suggests that:

Accepted Answer

A)   star formation occurs inside the spiral arms.
B)   the spiral arms' gravity pulls in nearby stars.
C)   all stars are confined to spiral arms.
D)   most stars end their lives in spiral arms.

Question 15

Which of the following components of the Milky Way formed first?

Accepted Answer

A)   stars in the disk
B)   globular clusters
C)   the bulge
D)   the bar

Question 16

How does the stellar population within a few parsecs of the galactic center differ from the rest of the bulge?

Accepted Answer

A)   It is made up of more massive stars.
B)   It is made up of redder stars.
C)   It is made up of lower metallicity stars.
D)   It is made up of stars with slower orbital velocities.

Question 17

The figure below shows a pair of rotation curves.Which of the following statements correctly matches the curve to astronomical systems? Consider only the shape of the curve in answering this question.

Accepted Answer

A)   Curve A describes both the Milky Way and the Solar System.
B)   Curve B describes both the Milky Way and the Solar System.
C)   Curve A describes the Milky Way, while curve B describes the Solar System.
D)   Curve B describes the Milky Way, while curve A describes the Solar System.

Question 18

Where is the density of gas clouds largest within the disk of the Milky Way?

Accepted Answer

A)   at large radii and inside spiral arms
B)   at large radii and outside spiral arms
C)   at small radii and inside spiral arms
D)   at small radii and outside spiral arms

Question 19

Which of the following helps prove that spiral structure is not a result of the winding action of galactic rotation?

Accepted Answer

A)   the appearance of molecular clouds inside spiral arms
B)   the 21-cm line
C)   the orbital period of the Sun around the Milky Way
D)   the presence of a bulge

Question 20

Why are O and B stars preferentially found within spiral arms?

Accepted Answer

Because they are bor...

Exam 15: Our City of Stars: the Milky Way

The appearance of O and B stars in spiral arms suggests that:

Correct AnswerverifiedShow Answer

How does the fraction of heavy elements inside gas clouds vary with location in the Milky Way's disk?

Correct AnswerverifiedIt decreases with di...View AnswerShow Answer

Where is the Sun located within the Milky Way?

Correct AnswerverifiedShow Answer

During the formation of the Milky Way,why did the gas collapse to a disk while the stars remained in a spherical distribution?

Correct AnswerverifiedGas clouds collide w...View AnswerShow Answer

Where is the density of gas clouds largest within the disk of the Milky Way?

Correct AnswerverifiedShow Answer

Why are O and B stars preferentially found within spiral arms?

Correct AnswerverifiedBecause they are bor...View AnswerShow Answer

The figure below shows a spiral arm inside a galaxy.Relative to the spiral arm,in which direction (if any)are the gas and stars inside the galaxy moving?

Correct AnswerverifiedFrom right...View AnswerShow Answer

Which of the following stars is most likely to have formed in a spiral arm?

Correct AnswerverifiedShow Answer

How does the stellar population within a few parsecs of the galactic center differ from the rest of the bulge?

Correct AnswerverifiedShow Answer

An observer far from any city lights might see the feature shown in the figure below at night.What generates the diffuse light seen here?

Correct AnswerverifiedStars in t...View AnswerShow Answer

Which of the following helps prove that spiral structure is not a result of the winding action of galactic rotation?

Correct AnswerverifiedShow Answer

How many stars does an "average" galaxy like the Milky Way have?

Correct AnswerverifiedShow Answer

Why is the metallicity of Population I stars greater than that of Population II stars?

Correct AnswerverifiedPopulation I stars formed afte...View AnswerShow Answer

Why do older stars tend to be at larger heights above the midplane of the Milky Way's disk?

Correct AnswerverifiedShow Answer

Which of the following components of the Milky Way formed first?

Correct AnswerverifiedShow Answer

The figure below shows the rotation curve of a galaxy.How does the mass enclosed within a given distance from the galaxy's center vary?

Correct AnswerverifiedShow Answer

How do stars in the disk of the Milky Way move?

Correct AnswerverifiedShow Answer

The Magellanic Stream is evidence of:

Correct AnswerverifiedShow Answer

How did Harlow Shapley avoid the bias of dust when measuring the size and shape of the Milky Way?

Correct AnswerverifiedShow Answer

The figure below shows a pair of rotation curves.Which of the following statements correctly matches the curve to astronomical systems? Consider only the shape of the curve in answering this question.

Correct AnswerverifiedShow Answer

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It decreases with di...
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Gas clouds collide w...
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Because they are bor...
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From right...
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Stars in t...
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Population I stars formed afte...
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