Question 1

If the spiral density wave were the only thing producing spiral arms,it would be expected that

Accepted Answer

A)   all spiral arms would be dust free.
B)   all galaxies would have grand design spiral patterns.
C)   the Milky Way would be more massive than observed.
D)   the Milky Way wouldn't have any spiral arms.
E)   the halo component of the Milky way would show spiral arms as well.

Question 2

The magnetic field of the galaxy

Accepted Answer

A)   is stronger than the magnetic field of the sun.
B)   traps cosmic rays in the disk of the galaxy.
C)   creates the spiral density waves that initiate star formation.
D)   forces the halo stars to follow highly inclined orbits.
E)   produces 21-cm radiation that allows us to map the spiral arms.

Question 3

The center of our galaxy lies in the direction of the constellation of

Accepted Answer

A)   Ursa Minor.
B)   Ursa Major.
C)   Sagittarius.
D)   Orion.
E)   Monoceros.

Question 4

Henrietta Leavitt discovered the period-luminosity relationship for ____________________.

Accepted Answer

The answer of Henrietta Leavitt discovered the period-luminosity relationship for...

Question 5

Younger stars formed not so long ago have more heavy elements than stars formed early in the history of our Galaxy because

Accepted Answer

A)   old stars destroy heavy elements as they age.
B)   young stars burn their nuclear fuels faster.
C)   heavy elements were made in previous generations of stars.
D)   all of the above
E)   heavy elements haven't had time to settle to the core of these younger stars.

Question 6

Diagram 15-1 
-Refer to Diagram 15-1.A type I Cepheid has been located in an open cluster.The period of the Cepheid variable is 30 days,and the variable's apparent visual magnitude is 10.What is the distance to this open cluster?

Accepted Answer

A)   100 pc
B)   10,000 pc
C)   20 pc
D)   300 pc
E)   2500 pc

Question 7

Old stars are poor in heavy atoms because there were no previous generations of stars.

Accepted Answer

A) True 
 B)False

Question 8

How is the age of the galaxy determined?

Accepted Answer

A)   Measuring the metallicity of Population II stars.
B)   Finding the turnoff point in the H-R diagram of globular clusters.
C)   From the motion of stars in the galactic halo.
D)   Counting the number of open clusters in the spiral arms.

Question 9

Shapley found the distance to the center of the galaxy by studying the distance to open clusters.

Accepted Answer

A) True 
 B)False

Question 10

The age of the Milky Way galaxy has been estimated to be at least 13 billion years based on

Accepted Answer

A)   observations of globular clusters.
B)   observations of open clusters.
C)   21cm radiation from H I regions.
D)   the rotation curve of the galaxy.
E)   the energy produced by Sagittarius A*

Question 11

Diagram 15-1 
-Refer to Diagram 15-1.A type II Cepheid has been located in a distant globular cluster with a period of 10 days.What is the star's absolute magnitude?

Accepted Answer

A)   (-1) 
B)   0
C)   (-4) 
D)  ( -6) 
E)   The absolute magnitude of a Cepheid variable cannot be determined unless its distance is known.

Question 12

The disk of the Milky Way is approximately 20,000 ly in diameter.

Accepted Answer

A) True 
 B)False

Question 13

Radio maps of the spiral arms of our galaxy

Accepted Answer

A)   reveal that our galaxy is a grand design spiral.
B)   map the location of Hot O and B stars by the radio radiation they emit.
C)   reveal that the spiral arms are winding up and growing closer together.
D)   reveal that the sun is currently located in the center of a spiral arm.
E)   map the location of dense neutral hydrogen clouds.

Question 14

Herschel's grindstone and Kapteyn's star system were too small because

Accepted Answer

A)   they did not count the brightest stars.
B)   they did not study the southern sky.
C)   they did not have large enough telescopes.
D)   they only observed stars in the disk of the galaxy and not the halo.
E)   they did not know about interstellar dust clouds.

Question 15

Halo stars located in the disk are easy to detect because they

Accepted Answer

A)   are the only low mass stars in the disk.
B)   are only found in globular clusters.
C)   are primarily O and B supergiants.
D)   move at an angle across the disk.
E)   emit cosmic rays.

Question 16

Radio maps of our galaxy show spiral arms because the

Accepted Answer

A)   arms have high Doppler shifts.
B)   gas in the spiral arms is hot enough to emit photons.
C)   dust in spiral arms is more dense than it is between the spiral arms.
D)   gas in spiral arms is more dense than it is between the spiral arms.
E)   stars in the spiral arms emit most of their energy at radio wavelengths.

Question 17

How did Harlow Shapley determine where the center of the galaxy lies?

Accepted Answer

A)   He plotted the distribution of open clusters.
B)   He plotted the distribution of globular clusters.
C)   He made star counts in every direction of the galactic disk.
D)   He measured the amount of dust obscuration in every direction of the galactic disk.

Question 18

The ____________________ of the galaxy contains population I stars,open clusters,and gas clouds.

Accepted Answer

The answer of The ____________________ of the galaxy contains population...

Question 19

Our Milky Way Galaxy is about...

Accepted Answer

A)   1 light year across
B)   10 light years across
C)   100 light years across
D)   1000 light years across
E)   100,000 light years across

Question 20

A several million solar mass ____ is thought to be at the center of our galaxy.

Accepted Answer

A)   spiral arm
B)   globular cluster
C)   planet
D)   black hole

Exam 15: The Milky Way Galaxy

Halo stars located in the disk are easy to detect because they

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Diagram 15-1 -Refer to Diagram 15-1.A type I Cepheid has been located in an open cluster.The period of the Cepheid variable is 30 days,and the variable's apparent visual magnitude is 10.What is the distance to this open cluster?

Correct AnswerverifiedShow Answer

Old stars are poor in heavy atoms because there were no previous generations of stars.

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Henrietta Leavitt discovered the period-luminosity relationship for ____________________.

Correct AnswerverifiedShow Answer

The age of the Milky Way galaxy has been estimated to be at least 13 billion years based on

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How did Harlow Shapley determine where the center of the galaxy lies?

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Radio maps of our galaxy show spiral arms because the

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The magnetic field of the galaxy

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How is the age of the galaxy determined?

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Radio maps of the spiral arms of our galaxy

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If the spiral density wave were the only thing producing spiral arms,it would be expected that

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The center of our galaxy lies in the direction of the constellation of

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The disk of the Milky Way is approximately 20,000 ly in diameter.

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A several million solar mass ____ is thought to be at the center of our galaxy.

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Younger stars formed not so long ago have more heavy elements than stars formed early in the history of our Galaxy because

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Herschel's grindstone and Kapteyn's star system were too small because

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Diagram 15-1 -Refer to Diagram 15-1.A type II Cepheid has been located in a distant globular cluster with a period of 10 days.What is the star's absolute magnitude?

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Our Milky Way Galaxy is about...

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Shapley found the distance to the center of the galaxy by studying the distance to open clusters.

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The ____________________ of the galaxy contains population I stars,open clusters,and gas clouds.

Correct AnswerverifiedShow Answer

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