Question 1

In general, Population I stars are _________ than Population II stars.

Accepted Answer

A)   older
B)   younger
C)   the same age
D)   sometimes older, and sometimes youngerE) B) and D)
F) A) and B)

Question 2

Stars in globular clusters belong to Population ___.

Accepted Answer

A)   I
B)   II
C)   III
D)   ZeroE) B) and C)
F) A) and C)

Question 3

According to the density-wave theory, spiral arms are blue because they

Accepted Answer

A)   contain many reflection nebulae from sites of young star formation.
B)   contain only young stars, whose formation was triggered by the explosion of older red stars just in front of the spiral arm.
C)   contain a lot of young stars formed from clouds compressed by the density wave.
D)   have too much metal content to form red stars.E) A) and C)
F) A) and B)

Question 4

Which radiation is the most useful to map the structure of our Galaxy?

Accepted Answer

A)   far ultraviolet
B)   21-cm radio radiation
C)   X-rays
D)   gamma raysE) A) and B)
F) All of the above

Question 5

Which of the following may explain the failure to observe Population III stars?

Accepted Answer

A)   We do not expect to observe Population III stars, because pure hydrogen and helium stars never formed.
B)   Population III stars had their surfaces contaminated by remnants of massive stars.
C)   The first stars to be formed in the young Milky Way are too far away to be detected.
D)   None of these choices is correct.E) A) and B)
F) A) and C)

Question 6

The Solar System is located about ___ from the center of the Milky Way.

Accepted Answer

A)   8 kiloparsecs
B)   8 light-years
C)   8 AU
D)   8 parsecsE) A) and D)
F) C) and D)

Question 7

Astronomers believe that the massive object at the center of the Milky Way is a black hole because

Accepted Answer

A)   images show an accretion disk surrounding an empty spot.
B)   gravitational wave measurements indicate a black hole is there.
C)   observations at X-ray waves, infrared waves, and radio waves limit the size of the object to smaller than 10 AU.
D)   it is necessary to explain the Galaxy's rotation curve.E) All of the above
F) A) and B)

Question 8

The Solar System is about 5 billion years old and completes one orbit around the center of the Milky Way in 220 million years. Therefore, we conclude that the Solar system has completed a total of about ___ orbits around the Galactic center.

Accepted Answer

A)   5
B)   10
C)   22
D)   50E) A) and C)
F) All of the above

Question 9

The radio waves emitted from Sagittarius A* region take how long to travel to Earth?

Accepted Answer

A)   50,000 years
B)   100,000 years
C)   8.5 years
D)   220 million yearsE) A) and D)
F) None of the above

Question 10

Astronomers have found the black hole at the center of the Milky Way has a mass of about _________ solar masses.

Accepted Answer

A)   40
B)   4 hundred thousand
C)   4 million
D)   4 billionE) C) and D)
F) A) and B)

Question 11

Astronomers think the Milky Way has spiral arms because

Accepted Answer

A)   they can see them unwinding along the celestial equator.
B)   X-ray maps show that dust clouds are distributed in the disk with a spiral pattern.
C)   young star clusters, HII regions, and associations outline spiral arms.
D)   globular clusters outline spiral arms.
E)   All of these choices are correct.F) None of the above
G) A) and C)

Question 12

Although it hasn't been observed (yet) , why do astronomers think that the Milky Way may contain "dark" material?

Accepted Answer

A)   Theory predicts that there should be more black holes than we've so far detected.
B)   The Galaxy's gravity seems too big for the mass astronomers can see.
C)   Due to its large size, the light from stars on the other side of the Milky Way has not reached us yet.
D)   Astronomers have detected neutrinos from unseen sources.E) B) and C)
F) A) and D)

Question 13

The estimated age of the Milky Way Galaxy is about ___________.

Accepted Answer

A)   20 billion years
B)   100,000 years
C)   13 billion years
D)   4.6 billion yearsE) None of the above
F) A) and B)

Question 14

What is the zone of avoidance?

Accepted Answer

A)   a part of the region of the Solar System where it is too dangerous to send spacecraft
B)   a quadrant of the Galaxy where no galaxies exist
C)   a part of the sky in which astronomers cannot observe due to bright emission from interstellar dust
D)   the region of the sky where no galaxies are seen due to obscuring dust in the Milky WayE) A) and B)
F) A) and C)

Question 15

New surveys suggest brown dwarfs, stars under the critical mass for stable fusion, are probably very rare.

Accepted Answer

A) True 
 B)False

Question 16

One difference between Population I and Population II stars in the Milky Way is

Accepted Answer

A)   that Pop I stars produce energy by fusion and Pop II by fission.
B)   that Pop I stars have very few metals and Pop II stars are metal rich.
C)   that Pop I stars have orbits in the disk and Pop II stars have orbits that pass through the disk.
D)   that Pop I stars produce energy by fusion and Pop II stars through gravitational contraction.E) C) and D)
F) B) and C)

Exam 16: The Milky Way Galaxy

In general, Population I stars are _________ than Population II stars.

Correct Answer
verified

The estimated age of the Milky Way Galaxy is about ___________.

Correct Answer
verified

According to the density-wave theory, spiral arms are blue because they

Correct Answer
verified

Astronomers have found the black hole at the center of the Milky Way has a mass of about _________ solar masses.

Correct Answer
verified

Which of the following may explain the failure to observe Population III stars?

Correct Answer
verified

One difference between Population I and Population II stars in the Milky Way is

Correct Answer
verified

The radio waves emitted from Sagittarius A* region take how long to travel to Earth?

Correct Answer
verified

New surveys suggest brown dwarfs, stars under the critical mass for stable fusion, are probably very rare.

Correct Answer
verified

Astronomers think the Milky Way has spiral arms because

Correct Answer
verified

The Solar System is located about ___ from the center of the Milky Way.

Correct Answer
verified

What is the zone of avoidance?

Correct Answer
verified

Astronomers believe that the massive object at the center of the Milky Way is a black hole because

Correct Answer
verified

Although it hasn't been observed (yet) , why do astronomers think that the Milky Way may contain "dark" material?

Correct Answer
verified

The Solar System is about 5 billion years old and completes one orbit around the center of the Milky Way in 220 million years. Therefore, we conclude that the Solar system has completed a total of about ___ orbits around the Galactic center.

Correct Answer
verified

Which radiation is the most useful to map the structure of our Galaxy?

Correct Answer
verified

Stars in globular clusters belong to Population ___.

Correct Answer
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Exam 16: The Milky Way Galaxy

In general, Population I stars are _________ than Population II stars.

Correct AnswerverifiedShow Answer

The estimated age of the Milky Way Galaxy is about ___________.

Correct AnswerverifiedShow Answer

According to the density-wave theory, spiral arms are blue because they

Correct AnswerverifiedShow Answer

Astronomers have found the black hole at the center of the Milky Way has a mass of about _________ solar masses.

Correct AnswerverifiedShow Answer

Which of the following may explain the failure to observe Population III stars?

Correct AnswerverifiedShow Answer

One difference between Population I and Population II stars in the Milky Way is

Correct AnswerverifiedShow Answer

The radio waves emitted from Sagittarius A* region take how long to travel to Earth?

Correct AnswerverifiedShow Answer

New surveys suggest brown dwarfs, stars under the critical mass for stable fusion, are probably very rare.

Correct AnswerverifiedShow Answer

Astronomers think the Milky Way has spiral arms because

Correct AnswerverifiedShow Answer

The Solar System is located about ___ from the center of the Milky Way.

Correct AnswerverifiedShow Answer

What is the zone of avoidance?

Correct AnswerverifiedShow Answer

Astronomers believe that the massive object at the center of the Milky Way is a black hole because

Correct AnswerverifiedShow Answer

Although it hasn't been observed (yet) , why do astronomers think that the Milky Way may contain "dark" material?

Correct AnswerverifiedShow Answer

The Solar System is about 5 billion years old and completes one orbit around the center of the Milky Way in 220 million years. Therefore, we conclude that the Solar system has completed a total of about ___ orbits around the Galactic center.

Correct AnswerverifiedShow Answer

Which radiation is the most useful to map the structure of our Galaxy?

Correct AnswerverifiedShow Answer

Stars in globular clusters belong to Population ___.

Correct AnswerverifiedShow Answer

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