Question 1

Discuss how astronomers know that our galaxy contains spiral arms in its disk.

Accepted Answer

The answer of Discuss how astronomers know that our galaxy...

Question 2

What behaviour of galactic rotation curves suggests the existence of dark matter in an extended halo?

Accepted Answer

A)  Small velocities are seen at large distances from the galactic centre.
B)  Small velocities are seen at distances close to the galactic centre.
C)  Large velocities are seen at large distances from the galactic centre.
D)  Large velocities are seen at distances close to the galactic centre.

Question 3

Which of the following is NOT explained by the traditional theory of the formation of our galaxy?

Accepted Answer

A)  the existence of the nuclear bulge
B)  the existence of the disk of the galaxy
C)  the fact that the oldest stars in the galaxy are not metal-free
D)  the difference in metal abundance of the population I and II stars

Question 4

Spiral tracers tend to be old,luminous stars.

Accepted Answer

A) True 
 B)False

Question 5

How does the density wave theory explain the presence of young stars in the spiral arms?

Accepted Answer

The answer of How does the density wave theory explain...

Question 6

Why are O and B stars good tracers of spiral structure?

Accepted Answer

A)  They are young and luminous.
B)  They are old and have been part of the galaxy for a long time.
C)  They are young and moving with large radial velocities.
D)  They were formed in the galaxy's halo.

Question 7

The orbits of halo stars are typically circular and have a low inclination with respect to the disk.

Accepted Answer

A) True 
 B)False

Question 8

The disk of the galaxy is older than the halo.

Accepted Answer

A) True 
 B)False

Question 9

If spiral density waves were the only thing producing spiral arms,what result would be expected?

Accepted Answer

A)  All spiral arms would be gas- and dust-free.
B)  All galaxies would have only two smooth spiral arms.
C)  The Milky Way would show an irregular pattern of short arms.
D)  The halo component of the Milky Way would show spiral arms as well.

Question 10

-Refer to the figure.Polaris is a Type I Cepheid with a period of 4 days.What is its absolute magnitude?

Accepted Answer

A)  +1
B)  0.0
C)  -1.0
D)  -3.5

Question 11

What is the difference between a population I star and a population II star?

Accepted Answer

The answer of What is the difference between a population...

Question 12

Compare and contrast the properties of disk and halo stars.

Accepted Answer

The answer of Compare and contrast the properties of disk...

Question 13

How does the traditional theory of the formation of the galaxy explain the origin of globular clusters?

Accepted Answer

A)  They formed in the disk and were later ejected to the halo.
B)  They built up over time from the collisions of stars in the halo.
C)  They formed in other galaxies and were captured by close interactions.
D)  They formed early on during the free-fall collapse of the proto-galactic material.

Question 14

What is the main component of the central bulge of our galaxy?

Accepted Answer

A)  gas and dust
B)  population I stars
C)  stars associated with the spherical component of our galaxy
D)  stars associated with the disk component of our galaxy

Question 15

Giant molecular cloud complexes are located in spiral arms.

Accepted Answer

A) True 
 B)False

Question 16

Why does the rotation of our galaxy suggest that it is more massive than previously thought?

Accepted Answer

The answer of Why does the rotation of our galaxy...

Question 17

What is the difference between an open cluster,an association,and a globular cluster? In which parts of the galaxy is each found?

Accepted Answer

Open clusters, also known as galactic cl...

Question 18

What do radio maps of the spiral arms of our galaxy show?

Accepted Answer

A)  They reveal that our galaxy is a grand design spiral.
B)  They map the location of dense neutral hydrogen clouds.
C)  They reveal that the Sun is currently located in the centre of a spiral arm.
D)  They map the location of hot O and B stars by the radio radiation they emit.

Question 19

-In the diagram,the approximate absolute magnitude of a Type II Cepheid with a period of 30 days is _________________.

Accepted Answer

The answer of 
-In the diagram,the approximate absolute magnitude of...

Question 20

-Refer to the figure.If you observe the period of a type II Cepheid and mistakenly think it's a type I Cepheid,what incorrect conclusion will you draw?

Accepted Answer

A)  You will measure the wrong period.
B)  You will think the Cepheid is farther away than it actually is.
C)  You will think the Cepheid is closer than it actually is.
D)  You will think the Cepheid is less luminous than it actually is.

Exam 9: The Milky Way Galaxy

What is the main component of the central bulge of our galaxy?

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-In the diagram,the approximate absolute magnitude of a Type II Cepheid with a period of 30 days is _________________.

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Which of the following is NOT explained by the traditional theory of the formation of our galaxy?

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What do radio maps of the spiral arms of our galaxy show?

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Why does the rotation of our galaxy suggest that it is more massive than previously thought?

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-Refer to the figure.Polaris is a Type I Cepheid with a period of 4 days.What is its absolute magnitude?

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What is the difference between a population I star and a population II star?

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The orbits of halo stars are typically circular and have a low inclination with respect to the disk.

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Giant molecular cloud complexes are located in spiral arms.

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How does the traditional theory of the formation of the galaxy explain the origin of globular clusters?

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Discuss how astronomers know that our galaxy contains spiral arms in its disk.

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The disk of the galaxy is older than the halo.

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-Refer to the figure.If you observe the period of a type II Cepheid and mistakenly think it's a type I Cepheid,what incorrect conclusion will you draw?

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How does the density wave theory explain the presence of young stars in the spiral arms?

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Why are O and B stars good tracers of spiral structure?

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If spiral density waves were the only thing producing spiral arms,what result would be expected?

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Spiral tracers tend to be old,luminous stars.

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What behaviour of galactic rotation curves suggests the existence of dark matter in an extended halo?

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What is the difference between an open cluster,an association,and a globular cluster? In which parts of the galaxy is each found?

Correct AnswerAnswered by ExamLex AIOpen clusters, also known as galactic cl...View AnswerShow Answer

Compare and contrast the properties of disk and halo stars.

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Open clusters, also known as galactic cl...
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