Question 1

On an H- R diagram, a protostar would be

Accepted Answer

A)   below and near the right side of the main sequence.
B)   above and near the upper left of the main sequence.
C)   on the main sequence at the extreme lower right.
D)   below and to the left of the main sequence.
E)   above and to the right of the main sequence.F) A) and C)
G) B) and C)

Question 2

A photosphere appears on a protostar near the end of stage

Accepted Answer

A)   1.
B)   2.
C)   3.
D)   6.
E)   7.F) B) and E)
G) A) and B)

Question 3

Dark nebulae are opaque to all wavelengths of electromagnetic radiation.

Accepted Answer

A) True 
 B)False

Question 4

Bright blue stars are typical of young star clusters.

Accepted Answer

The answer of Bright blue stars are typical of young...

Question 5

Why are dark dust clouds largely misnamed?

Accepted Answer

A)   They contain much more gas than dust.
B)   It is ice, not dust, which make them look dark.
C)   Dust clouds do radiate energy, but not as much light as the stars do.
D)   The cloud is an illusion, for the dust is evenly distributed around the Galaxy.
E)   All of the above are correct.F) All of the above
G) A) and E)

Question 6

The average temperature of the typical dark dust cloud is about

Accepted Answer

A)   0 K.
B)   2.73 K.
C)   100 K.
D)   3,000 K.
E)   6,000 K.F) A) and B)
G) B) and C)

Question 7

What is the critical temperature for stage 7; why?

Accepted Answer

The core must reach 15 million...

Question 8

Almost all of the complex molecules found in space are based on atoms.

Accepted Answer

A)   silicon
B)   carbon
C)   oxygen
D)   hydrogen
E)   ironF) A) and D)
G) A) and C)

Question 9

What information does 21- cm radiation provide about the gas clouds?

Accepted Answer

A)   their density
B)   their motion
C)   their temperature
D)   their distribution
E)   all of the aboveF) None of the above
G) A) and D)

Question 10

The spectra of interstellar gas clouds show that they have the same basic composition as

Accepted Answer

A)   asteroids.
B)   Earth's atmosphere.
C)   interstellar dust.
D)   stars.
E)   the Martian polar caps.F) A) and E)
G) A) and D)

Question 11

Why do new stars generally form in close proximity?

Accepted Answer

As a gas cloud collapses, it breaks into...

Question 12

What two things are needed to create an emission nebula?

Accepted Answer

A)   interstellar gas and dust
B)   hydrogen fusion and helium ionization
C)   hydrogen gas and carbon dust
D)   hot stars and interstellar gas, particularly hydrogen
E)   cool stars and much interstellar dustF) C) and D)
G) A) and D)

Question 13

Contrast the chemical composition of interstellar gas with that of interstellar dust.

Accepted Answer

Gas is almost all hydrogen and...

Question 14

What are thought to be some possible causes of triggering the contraction of an interstellar cloud?

Accepted Answer

The shockwave from the formati...

Question 15

Contrast the appearance of the H- R diagrams of a young open and old globular cluster.

Accepted Answer

In a young cluster, the main sequence is...

Question 16

While ionized hydrogen glows bright red, neutral hydrogen is transparent visibly and best studied with 21- cm radio waves.

Accepted Answer

A) True 
 B)False

Question 17

What is the primary visible color of an emission nebula?

Accepted Answer

A)   red due to the Ha line of hydrogen
B)   black, because of dust
C)   blue due to ionized helium atoms
D)   blue from the scattering of light off the tiny molecules
E)   red because of reddening by dustF) C) and D)
G) B) and D)

Question 18

What happens to light passing through even thin clouds of dust?

Accepted Answer

A)   Even a little can completely block all light, such as the Horsehead Nebula.
B)   It dims and reddens the light of all more distant stars.
C)   Its motion causes the light of stars beyond to twinkle.
D)   The light that passes through them is blueshifted due to the cloud's approach.
E)   Its motion causes all light to be redshifted as it passes through these clouds.F) A) and B)
G) C) and D)

Question 19

Most molecules found in the interstellar medium are based on carbon.

Accepted Answer

A) True 
 B)False

Question 20

What is the Local Bubble?

Accepted Answer

The Local Bubble is a large region, appr...

Exam 12: The Interstellar Medium: Star Formation in the Milky Way

What information does 21- cm radiation provide about the gas clouds?

Correct AnswerverifiedShow Answer

While ionized hydrogen glows bright red, neutral hydrogen is transparent visibly and best studied with 21- cm radio waves.

Correct AnswerverifiedShow Answer

What is the critical temperature for stage 7; why?

Correct AnswerverifiedThe core must reach 15 million...View AnswerShow Answer

What two things are needed to create an emission nebula?

Correct AnswerverifiedShow Answer

Most molecules found in the interstellar medium are based on carbon.

Correct AnswerverifiedShow Answer

The average temperature of the typical dark dust cloud is about

Correct AnswerverifiedShow Answer

Why do new stars generally form in close proximity?

Correct AnswerverifiedAs a gas cloud collapses, it breaks into...View AnswerShow Answer

Almost all of the complex molecules found in space are based on atoms.

Correct AnswerverifiedShow Answer

What are thought to be some possible causes of triggering the contraction of an interstellar cloud?

Correct AnswerverifiedThe shockwave from the formati...View AnswerShow Answer

On an H- R diagram, a protostar would be

Correct AnswerverifiedShow Answer

Why are dark dust clouds largely misnamed?

Correct AnswerverifiedShow Answer

The spectra of interstellar gas clouds show that they have the same basic composition as

Correct AnswerverifiedShow Answer

What is the Local Bubble?

Correct AnswerverifiedThe Local Bubble is a large region, appr...View AnswerShow Answer

Bright blue stars are typical of young star clusters.

Correct AnswerverifiedShow Answer

What is the primary visible color of an emission nebula?

Correct AnswerverifiedShow Answer

Contrast the appearance of the H- R diagrams of a young open and old globular cluster.

Correct AnswerverifiedIn a young cluster, the main sequence is...View AnswerShow Answer

What happens to light passing through even thin clouds of dust?

Correct AnswerverifiedShow Answer

A photosphere appears on a protostar near the end of stage

Correct AnswerverifiedShow Answer

Dark nebulae are opaque to all wavelengths of electromagnetic radiation.

Correct AnswerverifiedShow Answer

Contrast the chemical composition of interstellar gas with that of interstellar dust.

Correct AnswerverifiedGas is almost all hydrogen and...View AnswerShow Answer

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The core must reach 15 million...
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As a gas cloud collapses, it breaks into...
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The shockwave from the formati...
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The Local Bubble is a large region, appr...
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In a young cluster, the main sequence is...
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Correct Answer
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Gas is almost all hydrogen and...
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