Question 1

Briefly explain why stars that formed early in the history of the galaxy contain a smaller proportion of heavy elements than stars that formed more recently.

Accepted Answer

The star-gas-star cycle gradually enrich...

Question 2

Spiral arms appear bright because ________.

Accepted Answer

A)   they contain more hot young stars than other parts of the disk
B)   they contain far more stars than other parts of the galactic disk
C)   they contain more molecular clouds than other parts of the disk
D)   they are the only places where we find stars within the disk of the galaxyE) A) and C)
F) A) and D)

Question 3

How should we expect the Milky Way's interstellar medium to be different in 50 billion years than it is today?

Accepted Answer

A)   The total amount of gas will be much less than it is today.
B)   The total amount of gas will be about the same, but the percentage of elements heavier than hydrogen and helium will have risen from the current 2% to more than 50%.
C)   The total amount of gas will be much greater, since many stars will undergo supernovae between now and then.
D)   Thanks to the recycling of the star-gas-star cycle, the interstellar medium should look about the same in 50 billion years as it does today.E) A) and B)
F) A) and C)

Question 4

How are interstellar bubbles made?

Accepted Answer

A)   by the collapse of a gas cloud to form stars
B)   by the ejection of planetary nebulae from low-mass stars
C)   by the winds of massive stars and supernovae explosions
D)   by collisions between the Milky Way and satellite dwarf galaxies
E)   by the rapidly rotating magnetic fields of pulsarsF) None of the above
G) C) and D)

Question 5

Which of the following properties is more likely to be a characteristic of a halo star in the Milky Way, not a disk star?

Accepted Answer

A)   It orbits the center of the Milky Way galaxy.
B)   It has a low ratio of iron to hydrogen.
C)   It could be quite young.
D)   It is moving very slowly relative to the Sun's motion.E) B) and D)
F) A) and B)

Question 6

The primary way that we observe the atomic hydrogen that makes up most of the interstellar gas in the Milky Way is with ________.

Accepted Answer

A)   radio telescopes observing at a wavelength of 21 centimeters
B)   ground-based visible-light telescopes
C)   space-based ultraviolet telescopes
D)   X-ray telescopesE) A) and B)
F) C) and D)

Question 7

Open clusters and young stars are generally found only in the disk of the Milky Way and not in the halo.

Accepted Answer

A) True 
 B)False

Question 8

Where does most star formation occur in the Milky Way today?

Accepted Answer

A)   in the halo
B)   in the bulge
C)   in the spiral arms
D)   in the Galactic center
E)   uniformly throughout the GalaxyF) B) and E)
G) C) and D)

Question 9

Which of the following stars would be most likely to have the same abundance of elements heavier than helium as a red main sequence star in globular cluster M13?

Accepted Answer

A)   None of these choices
B)   Red giant in globular cluster M13
C)   A red main sequence star in the disk of the Milky WayD) All of the above
E) B) and C)

Question 10

Why do spiral arms have a blue color?

Accepted Answer

Spiral arms are waves of enhanced densit...

Question 11

All the following types of objects are found almost exclusively in the disk (rather than the halo)  of the Milky Way except ________.

Accepted Answer

A)   globular clusters
B)   young stars
C)   X-ray binaries
D)   high-mass, red supergiant starsE) None of the above
F) All of the above

Question 12

What is the most abundant molecule in interstellar clouds besides molecular hydrogen?

Accepted Answer

A)   molecular helium
B)   water
C)   carbon monoxide
D)   ammonia
E)   methaneF) A) and B)
G) B) and D)

Exam 14: Our Galaxy

The primary way that we observe the atomic hydrogen that makes up most of the interstellar gas in the Milky Way is with ________.

Correct Answer
verified

Spiral arms appear bright because ________.

Correct Answer
verified

Why do spiral arms have a blue color?

Correct Answer
verified
Spiral arms are waves of enhanced densit...
View Answer

Where does most star formation occur in the Milky Way today?

Correct Answer
verified

What is the most abundant molecule in interstellar clouds besides molecular hydrogen?

Correct Answer
verified

How should we expect the Milky Way's interstellar medium to be different in 50 billion years than it is today?

Correct Answer
verified

Which of the following stars would be most likely to have the same abundance of elements heavier than helium as a red main sequence star in globular cluster M13?

Correct Answer
verified

Open clusters and young stars are generally found only in the disk of the Milky Way and not in the halo.

Correct Answer
verified

Briefly explain why stars that formed early in the history of the galaxy contain a smaller proportion of heavy elements than stars that formed more recently.

Correct Answer
verified
The star-gas-star cycle gradually enrich...
View Answer

Which of the following properties is more likely to be a characteristic of a halo star in the Milky Way, not a disk star?

Correct Answer
verified

All the following types of objects are found almost exclusively in the disk (rather than the halo) of the Milky Way except ________.

Correct Answer
verified

How are interstellar bubbles made?

Correct Answer
verified

Exam 14: Our Galaxy

The primary way that we observe the atomic hydrogen that makes up most of the interstellar gas in the Milky Way is with ________.

Correct AnswerverifiedShow Answer

Spiral arms appear bright because ________.

Correct AnswerverifiedShow Answer

Why do spiral arms have a blue color?

Correct AnswerverifiedSpiral arms are waves of enhanced densit...View AnswerShow Answer

Where does most star formation occur in the Milky Way today?

Correct AnswerverifiedShow Answer

What is the most abundant molecule in interstellar clouds besides molecular hydrogen?

Correct AnswerverifiedShow Answer

How should we expect the Milky Way's interstellar medium to be different in 50 billion years than it is today?

Correct AnswerverifiedShow Answer

Which of the following stars would be most likely to have the same abundance of elements heavier than helium as a red main sequence star in globular cluster M13?

Correct AnswerverifiedShow Answer

Open clusters and young stars are generally found only in the disk of the Milky Way and not in the halo.

Correct AnswerverifiedShow Answer

Briefly explain why stars that formed early in the history of the galaxy contain a smaller proportion of heavy elements than stars that formed more recently.

Correct AnswerverifiedThe star-gas-star cycle gradually enrich...View AnswerShow Answer

Which of the following properties is more likely to be a characteristic of a halo star in the Milky Way, not a disk star?

Correct AnswerverifiedShow Answer

All the following types of objects are found almost exclusively in the disk (rather than the halo) of the Milky Way except ________.

Correct AnswerverifiedShow Answer

How are interstellar bubbles made?

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Spiral arms are waves of enhanced densit...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The star-gas-star cycle gradually enrich...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified