Question 1

There is no upper limit to the mass of a neutron star.

Accepted Answer

A) True 
 B)False

Question 2

From a theoretical standpoint, what is a pulsar?

Accepted Answer

A)  a star that alternately expands and contracts in size 
B)  a rapidly rotating neutron star 
C)  a neutron star or black hole that happens to be in a binary system 
D)  a binary system that happens to be aligned so that one star periodically eclipses the other 
E)  a star that is burning iron in its core 
A)  a star that alternately expands and contracts in size 
B)  a rapidly rotating neutron star 
C)  a neutron star or black hole that happens to be in a binary system 
D)  a binary system that happens to be aligned so that one star periodically eclipses the other 
E)  a star that is burning iron in its core

Question 3

What is an accretion disk?

Accepted Answer

A)  A disk of hot gas swirling rapidly around a white dwarf, neutron star, or black hole 
B)  Any flattened disk in space, such as the disk of the Milky Way Galaxy 
C)  A stream of gas flowing from one star to its binary companion star 
D)  A disk of material found around every white dwarf in the Milky Way Galaxy 
A)  A disk of hot gas swirling rapidly around a white dwarf, neutron star, or black hole 
B)  Any flattened disk in space, such as the disk of the Milky Way Galaxy 
C)  A stream of gas flowing from one star to its binary companion star 
D)  A disk of material found around every white dwarf in the Milky Way Galaxy

Question 4

Briefly describe what you would see if your friend plunged into a black hole.

Accepted Answer

As he approached the black hole, he woul

Question 5

What makes us think that the star system Cygnus X-1 contains a black hole?

Accepted Answer

A)  It emits X-rays characteristic of an accretion disk, but the unseen star in the system is too massive to be a neutron star. 
B)  No light is emitted from this star system, so it must contain a black hole. 
C)  The fact that we see strong X-ray emission tells us that the system must contain a black hole. 
D)  Cygnus X-1 is a powerful X-ray burster, so it must contain a black hole. 
A)  It emits X-rays characteristic of an accretion disk, but the unseen star in the system is too massive to be a neutron star. 
B)  No light is emitted from this star system, so it must contain a black hole. 
C)  The fact that we see strong X-ray emission tells us that the system must contain a black hole. 
D)  Cygnus X-1 is a powerful X-ray burster, so it must contain a black hole.

Question 6

Order the following objects in increasing size (radius):

Accepted Answer

A)  Jupiter, white dwarf, neutron star, Sun 
B)  neutron star, white dwarf, Jupiter, Sun 
C)  Jupiter, white dwarf, Sun, neutron star 
D)  neutron star, Jupiter, white dwarf, Sun 
A)  Jupiter, white dwarf, neutron star, Sun 
B)  neutron star, white dwarf, Jupiter, Sun 
C)  Jupiter, white dwarf, Sun, neutron star 
D)  neutron star, Jupiter, white dwarf, Sun

Question 7

Which of the following statements about electron degeneracy pressure and neutron degeneracy pressure is true?

Accepted Answer

A)  Electron degeneracy pressure is the main source of pressure in white dwarfs, while neutron degeneracy pressure is the main source of pressure in neutron stars. 
B)  Both electron degeneracy pressure and neutron degeneracy pressure help govern the internal structure of a main-sequence star. 
C)  The life of a white dwarf is an ongoing battle between electron degeneracy pressure and neutron degeneracy pressure. 
D)  In a black hole, the pressure coming from neutron degeneracy pressure is slightly greater than that coming from electron degeneracy pressure. 
A)  Electron degeneracy pressure is the main source of pressure in white dwarfs, while neutron degeneracy pressure is the main source of pressure in neutron stars. 
B)  Both electron degeneracy pressure and neutron degeneracy pressure help govern the internal structure of a main-sequence star. 
C)  The life of a white dwarf is an ongoing battle between electron degeneracy pressure and neutron degeneracy pressure. 
D)  In a black hole, the pressure coming from neutron degeneracy pressure is slightly greater than that coming from electron degeneracy pressure.

Question 8

Which statement about pulsars is not thought to be true?

Accepted Answer

A)  Pulsars can form only in close binary systems. 
B)  All pulsars are neutron stars, but not all neutron stars are pulsars. 
C)  A pulsar must have a very strong magnetic field and rotate quite rapidly. 
D)  Pulsars are kept from collapsing by neutron degeneracy pressure. 
A)  Pulsars can form only in close binary systems. 
B)  All pulsars are neutron stars, but not all neutron stars are pulsars. 
C)  A pulsar must have a very strong magnetic field and rotate quite rapidly. 
D)  Pulsars are kept from collapsing by neutron degeneracy pressure.

Question 9

Could our Sun ever undergo a nova or a white-dwarf supernova event? Why or why not?

Accepted Answer

No, because both events can on

Question 10

If you had something the size of a sugar cube that was made of neutron star matter, it would weigh ________.

Accepted Answer

A)  about as much as a large mountain 
B)  about 50 pounds 
C)  as much as the entire Earth 
D)  about as much as a truck 
A)  about as much as a large mountain 
B)  about 50 pounds 
C)  as much as the entire Earth 
D)  about as much as a truck

Question 11

What causes the radio pulses of a pulsar?

Accepted Answer

A)  The vibration of the neutron star. 
B)  As the neutron star spins, beams of radio radiation sweep through space. If one of the beams crosses the Earth, we observe a pulse. 
C)  The neutron star undergoes periodic explosions of nuclear fusion that generate radio pulses. 
D)  The neutron star's orbiting companion periodically eclipses the radio waves that the neutron star emits. 
E)  A black hole near the neutron star absorbs energy and re-emits it as radio waves. 
A)  The vibration of the neutron star. 
B)  As the neutron star spins, beams of radio radiation sweep through space. If one of the beams crosses the Earth, we observe a pulse. 
C)  The neutron star undergoes periodic explosions of nuclear fusion that generate radio pulses. 
D)  The neutron star's orbiting companion periodically eclipses the radio waves that the neutron star emits. 
E)  A black hole near the neutron star absorbs energy and re-emits it as radio waves.

Question 12

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 even faster), with near perfect regularity. 
C)  An object that emits random "pulses" of light, sometimes with only a fraction of a second between pulses and other times with several days between pulses. 
D)  A star that changes color rapidly, from blue to red and back again. 
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 even faster), with near perfect regularity. 
C)  An object that emits random "pulses" of light, sometimes with only a fraction of a second between pulses and other times with several days between pulses. 
D)  A star that changes color rapidly, from blue to red and back again.

Question 13

What is the evidence that gamma-ray bursts originate from beyond the Milky Way Galaxy?

Accepted Answer

Gamma-ray bursts are distributed uniform

Question 14

Which statement about accretion disks is not true?

Accepted Answer

A)  The primary factor determining whether a white dwarf has an accretion disk is the white dwarf's mass. 
B)  The gas in the inner parts of the disk travels faster than the gas in the outer parts of the disk. 
C)  The gas in the inner parts of the disk is hotter than the gas in the outer parts of the disk. 
D)  Accretion disks are made primarily of hydrogen and helium gas. 
A)  The primary factor determining whether a white dwarf has an accretion disk is the white dwarf's mass. 
B)  The gas in the inner parts of the disk travels faster than the gas in the outer parts of the disk. 
C)  The gas in the inner parts of the disk is hotter than the gas in the outer parts of the disk. 
D)  Accretion disks are made primarily of hydrogen and helium gas.

Question 15

Light escaping from white dwarfs will show a gravitational redshift.

Accepted Answer

A) True 
 B)False

Question 16

Based on current evidence, which of the following statements about gamma ray bursts is true?

Accepted Answer

A)  All those that we have detected occurred in distant galaxies. 
B)  They come primarily from the Milky Way's central black hole. 
C)  They occur in the same types of close binary systems that produce X-ray bursts. 
D)  All gamma ray bursts are produced by supernovae. 
A)  All those that we have detected occurred in distant galaxies. 
B)  They come primarily from the Milky Way's central black hole. 
C)  They occur in the same types of close binary systems that produce X-ray bursts. 
D)  All gamma ray bursts are produced by supernovae.

Question 17

A teaspoonful of white dwarf material on Earth would weigh

Accepted Answer

A)  a few grams. 
B)  a few pounds. 
C)  a few tons. 
D)  about the same as Mt. Everest. 
E)  about the same as the Earth. 
A)  a few grams. 
B)  a few pounds. 
C)  a few tons. 
D)  about the same as Mt. Everest. 
E)  about the same as the Earth.

Question 18

Suppose you find an X-ray binary system that shows X-ray bursts. Is it possible that this system consists of a red giant and a black hole? Why or why not?

Accepted Answer

No. X-ray bursts occur when ac

Question 19

Suppose you drop a clock toward a black hole. As you look at the clock from a high orbit, what will you notice?

Accepted Answer

A)  Time on the clock will run slower as it approaches the black hole, and light from the clock will be increasingly redshifted. 
B)  Time on the clock will run faster as it approaches the black hole, and light from the clock will be increasingly blueshifted. 
C)  The clock will fall toward the black hole at a steady rate, so that you'll see it plunge through the event horizon within just a few minutes. 
D)  The clock will fall faster and faster, reaching the speed of light as it crosses the event horizon. 
A)  Time on the clock will run slower as it approaches the black hole, and light from the clock will be increasingly redshifted. 
B)  Time on the clock will run faster as it approaches the black hole, and light from the clock will be increasingly blueshifted. 
C)  The clock will fall toward the black hole at a steady rate, so that you'll see it plunge through the event horizon within just a few minutes. 
D)  The clock will fall faster and faster, reaching the speed of light as it crosses the event horizon.

Question 20

A white dwarf supernova event is very important to calibrating Hubble's Law. Why? Choose the best answer for the question.

Accepted Answer

A)  It can only happen to white dwarfs. 
B)  It is a very rare event. 
C)  It is a very luminous standard candle. 
D)  The white dwarf supernova in a galaxy tells us how fast a galaxy is expanding away from us. 
A)  It can only happen to white dwarfs. 
B)  It is a very rare event. 
C)  It is a very luminous standard candle. 
D)  The white dwarf supernova in a galaxy tells us how fast a galaxy is expanding away from us.

There is no upper limit to the mass of a neutron star.

From a theoretical standpoint, what is a pulsar?

What is an accretion disk?

Briefly describe what you would see if your friend plunged into a black hole.

What makes us think that the star system Cygnus X-1 contains a black hole?

Order the following objects in increasing size (radius):

Which of the following statements about electron degeneracy pressure and neutron degeneracy pressure is true?

Which statement about pulsars is not thought to be true?

Could our Sun ever undergo a nova or a white-dwarf supernova event? Why or why not?

If you had something the size of a sugar cube that was made of neutron star matter, it would weigh ________.

What causes the radio pulses of a pulsar?

From an observational standpoint, what is a pulsar?

What is the evidence that gamma-ray bursts originate from beyond the Milky Way Galaxy?

Which statement about accretion disks is not true?

Light escaping from white dwarfs will show a gravitational redshift.

Based on current evidence, which of the following statements about gamma ray bursts is true?

A teaspoonful of white dwarf material on Earth would weigh

Suppose you find an X-ray binary system that shows X-ray bursts. Is it possible that this system consists of a red giant and a black hole? Why or why not?

Suppose you drop a clock toward a black hole. As you look at the clock from a high orbit, what will you notice?

A white dwarf supernova event is very important to calibrating Hubble's Law. Why? Choose the best answer for the question.

Our Place in the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light: the Cosmic Messenger

Formation of Planetary Systems: Our Solar System and Beyond

Earth and the Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Our Star

Surveying the Stars

Star Stuff

Our Galaxy

Galaxies and the Foundation of Modern Cosmology

Dark Matter, Dark Energy, and the Fate of the Universe

The Beginning of Time

Life in the Universe

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Exam 13: Bizarre Stellar Graveyard

There is no upper limit to the mass of a neutron star.

From a theoretical standpoint, what is a pulsar?

What is an accretion disk?

Briefly describe what you would see if your friend plunged into a black hole.

What makes us think that the star system Cygnus X-1 contains a black hole?

Order the following objects in increasing size (radius):

Which of the following statements about electron degeneracy pressure and neutron degeneracy pressure is true?

Which statement about pulsars is not thought to be true?

Could our Sun ever undergo a nova or a white-dwarf supernova event? Why or why not?

If you had something the size of a sugar cube that was made of neutron star matter, it would weigh ________.

What causes the radio pulses of a pulsar?

From an observational standpoint, what is a pulsar?

What is the evidence that gamma-ray bursts originate from beyond the Milky Way Galaxy?

Which statement about accretion disks is not true?

Light escaping from white dwarfs will show a gravitational redshift.

Based on current evidence, which of the following statements about gamma ray bursts is true?

A teaspoonful of white dwarf material on Earth would weigh

Suppose you find an X-ray binary system that shows X-ray bursts. Is it possible that this system consists of a red giant and a black hole? Why or why not?

Suppose you drop a clock toward a black hole. As you look at the clock from a high orbit, what will you notice?

A white dwarf supernova event is very important to calibrating Hubble's Law. Why? Choose the best answer for the question.

Our Place in the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light: the Cosmic Messenger

Formation of Planetary Systems: Our Solar System and Beyond

Earth and the Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Our Star

Surveying the Stars

Star Stuff

Our Galaxy

Galaxies and the Foundation of Modern Cosmology

Dark Matter, Dark Energy, and the Fate of the Universe

The Beginning of Time

Life in the Universe

Filters