Question 1

Should we expect to find abundant amounts of gold and other rare-earth elements elsewhere in the universe?

Accepted Answer

Gold,platinum,and other rare-earth eleme...

Question 2

Planets have been detected around a pulsar.

Accepted Answer

A) True 
 B)False

Question 3

Imagine that our Sun were magically and suddenly replaced by a black hole of the same mass (1 solar mass) .What would happen to Earth in its orbit?

Accepted Answer

A)  Earth would almost instantly be sucked into oblivion in the black hole.
B)  Earth would orbit faster,but at the same distance.
C)  Earth would slowly spiral inward until it settled into an orbit about the size of Mercury's current orbit.
D)  Nothing-Earth's orbit would remain the same.E) C) and D)
F) All of the above

Question 4

Pulsars are thought to be

Accepted Answer

A)  accreting white dwarfs.
B)  rapidly rotating neutron stars.
C)  unstable high-mass stars.
D)  accreting black holes.E) All of the above
F) B) and D)

Question 5

Based on current understanding,the minimum mass of a black hole that forms during a massive star supernova is roughly

Accepted Answer

A)  0.5 solar masses.
B)  1.4 solar masses.
C)  3 solar masses.
D)  10 solar masses.E) A) and C)
F) B) and C)

Question 6

Which of the following is closest in size (radius) to a neutron star?

Accepted Answer

A)  Earth
B)  a city
C)  a football stadium
D)  a basketball
E)  the SunF) D) and E)
G) B) and C)

Question 7

How are elements more massive than iron produced?

Accepted Answer

A)  inside white dwarfs
B)  inside two merging white dwarfs
C)  inside neutron stars
D)  inside two merging neutron starsE) C) and D)
F) All of the above

Question 8

Which of the following is closest in mass to a white dwarf?

Accepted Answer

A)  the Moon
B)  Earth
C)  Jupiter
D)  Neptune
E)  the SunF) B) and E)
G) D) and E)

Question 9

How do we know what happens at the event horizon of a black hole?

Accepted Answer

A)  Physicists have created miniature black holes in the lab.
B)  Astronomers have sent spacecraft through the event horizon of a nearby black hole.
C)  Astronomers have analyzed the light from matter within the event horizon of many black holes.
D)  Astronomers have detected X-rays from accretion disks around black holes.
E)  We don't know for sure: we only know what to expect based on the predictions of general relativity.F) A) and D)
G) D) and E)

Question 10

Suppose a white dwarf is gaining mass because of accretion in a binary system.What happens if the mass someday reaches the 1.4-solar-mass limit?

Accepted Answer

A)  The white dwarf undergoes a catastrophic collapse,leading to a type of supernova that is somewhat different from that which occurs in a massive star but is comparable in energy.
B)  The white dwarf,which is made mostly of carbon,suddenly becomes much hotter in temperature and therefore is able to begin fusing the carbon.This turns the white dwarf back into a star supported against gravity by ordinary pressure.
C)  The white dwarf immediately collapses into a black hole,disappearing from view.
D)  A white dwarf can never gain enough mass to reach the limit because a strong stellar wind prevents the material from reaching it in the first place.E) All of the above
F) B) and C)

Question 11

From an observational standpoint,what is a pulsar?

Accepted Answer

A)  a star that slowly changes its brightness,getting dimmer and then brighter with a period of anywhere from a few hours to a few weeks
B)  an object that emits flashes of light several times per second or more,with near perfect regularity
C)  an object that emits random "pulses" of light that sometimes occur only a fraction of a second apart and other times stop for several days at a time
D)  a star that changes color rapidly,from blue to red and back again
E)  a star that rapidly changes size as it moves off the main sequenceF) A) and D)
G) None of the above

Question 12

After a massive-star supernova,what is left behind?

Accepted Answer

A)  always a white dwarf
B)  always a neutron star
C)  always a black hole
D)  either a white dwarf or a neutron star
E)  either a neutron star or a black holeF) C) and D)
G) A) and B)

Question 13

According to present understanding,a nova is caused by

Accepted Answer

A)  hydrogen fusion on the surface of a white dwarf.
B)  carbon fusion in the core of a white dwarf.
C)  hydrogen fusion on the surface of a neutron star.
D)  a white dwarf that gains enough mass to exceed the 1.4-solar-mass limit.E) All of the above
F) A) and D)

Question 14

Most of the gold,platinum,and rare-earth elements present in the universe are created by neutron star mergers.

Accepted Answer

A) True 
 B)False

Question 15

An advanced civilization lives on a planet orbiting a close binary star system that consists of a 15MSᵤn red giant and a 10MSᵤn black hole.Assume that the two stars are quite close together,so that an accretion disk surrounds the black hole.The planet on which the civilization lives orbits the binary star at a distance of 10 AU.
-Sometime within the next million years or so,their planet is likely to be doomed because

Accepted Answer

A)  jets of material shot out of the accretion disk will shoot down their planet.
B)  their planet receives most of its energy from the red giant.However,this star will soon be completely devoured in the accretion disk and thus will no longer exist.
C)  the red giant will probably undergo a supernova explosion within the next million years.
D)  tidal forces from the black hole will rip the planet apart.
E)  the planet's orbit gradually will decay as it is sucked in by the black hole.F) A) and C)
G) All of the above

Question 16

A teaspoonful of white dwarf material on Earth would weigh

Accepted Answer

A)  the same as a teaspoonful of Earth-like material.
B)  about the same as Mt.Everest.
C)  about the same as Earth.
D)  a few tons.
E)  a few million tons.F) A) and B)
G) D) and E)

Question 17

No visible light can escape a black hole,but things such as gamma rays,X-rays,and neutrinos can.

Accepted Answer

A) True 
 B)False

Exam 18: The Bizarre Stellar Graveyard

Based on current understanding,the minimum mass of a black hole that forms during a massive star supernova is roughly

Correct Answer
verified

No visible light can escape a black hole,but things such as gamma rays,X-rays,and neutrinos can.

Correct Answer
verified

From an observational standpoint,what is a pulsar?

Correct Answer
verified

Most of the gold,platinum,and rare-earth elements present in the universe are created by neutron star mergers.

Correct Answer
verified

Which of the following is closest in mass to a white dwarf?

Correct Answer
verified

How do we know what happens at the event horizon of a black hole?

Correct Answer
verified

How are elements more massive than iron produced?

Correct Answer
verified

A teaspoonful of white dwarf material on Earth would weigh

Correct Answer
verified

Correct Answer
verified

According to present understanding,a nova is caused by

Correct Answer
verified

Suppose a white dwarf is gaining mass because of accretion in a binary system.What happens if the mass someday reaches the 1.4-solar-mass limit?

Correct Answer
verified

After a massive-star supernova,what is left behind?

Correct Answer
verified

Imagine that our Sun were magically and suddenly replaced by a black hole of the same mass (1 solar mass) .What would happen to Earth in its orbit?

Correct Answer
verified

Which of the following is closest in size (radius) to a neutron star?

Correct Answer
verified

Planets have been detected around a pulsar.

Correct Answer
verified

Pulsars are thought to be

Correct Answer
verified

Should we expect to find abundant amounts of gold and other rare-earth elements elsewhere in the universe?

Correct Answer
verified
Gold,platinum,and other rare-earth eleme...
View Answer

Exam 18: The Bizarre Stellar Graveyard

Based on current understanding,the minimum mass of a black hole that forms during a massive star supernova is roughly

Correct AnswerverifiedShow Answer

No visible light can escape a black hole,but things such as gamma rays,X-rays,and neutrinos can.

Correct AnswerverifiedShow Answer

From an observational standpoint,what is a pulsar?

Correct AnswerverifiedShow Answer

Most of the gold,platinum,and rare-earth elements present in the universe are created by neutron star mergers.

Correct AnswerverifiedShow Answer

Which of the following is closest in mass to a white dwarf?

Correct AnswerverifiedShow Answer

How do we know what happens at the event horizon of a black hole?

Correct AnswerverifiedShow Answer

How are elements more massive than iron produced?

Correct AnswerverifiedShow Answer

A teaspoonful of white dwarf material on Earth would weigh

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

According to present understanding,a nova is caused by

Correct AnswerverifiedShow Answer

Suppose a white dwarf is gaining mass because of accretion in a binary system.What happens if the mass someday reaches the 1.4-solar-mass limit?

Correct AnswerverifiedShow Answer

After a massive-star supernova,what is left behind?

Correct AnswerverifiedShow Answer

Imagine that our Sun were magically and suddenly replaced by a black hole of the same mass (1 solar mass) .What would happen to Earth in its orbit?

Correct AnswerverifiedShow Answer

Which of the following is closest in size (radius) to a neutron star?

Correct AnswerverifiedShow Answer

Planets have been detected around a pulsar.

Correct AnswerverifiedShow Answer

Pulsars are thought to be

Correct AnswerverifiedShow Answer

Should we expect to find abundant amounts of gold and other rare-earth elements elsewhere in the universe?

Correct AnswerverifiedGold,platinum,and other rare-earth eleme...View AnswerShow Answer

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
verified
Gold,platinum,and other rare-earth eleme...
View Answer