Question 1

If you were to come back to our Solar System in 6 billion years, what might you expect to find?

Accepted Answer

A) a rapidly spinning pulsar 
B) a white dwarf 
C) a black hole 
D) a red giant star 
E) Everything will be essentially the same as it is now. 
A) a rapidly spinning pulsar 
B) a white dwarf 
C) a black hole 
D) a red giant star 
E) Everything will be essentially the same as it is now.

Question 2

The white dwarf that remains when our Sun dies will be mostly made of .

Accepted Answer

A) hydrogen 
B) carbon 
C) neutrons 
D) helium 
A) hydrogen 
B) carbon 
C) neutrons 
D) helium

Question 3

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

Question 4

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

Accepted Answer

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

Question 5

Explain why black holes in binary systems are associated with strong, steady X- ray emission.

Accepted Answer

In a binary system, the black hole can a

Question 6

What is the basic definition of a black hole?

Accepted Answer

A) any object made from dark matter 
B) a compact mass that emits no visible light 
C) an object with gravity so strong that not even light can escape 
D) a dead star that has faded from view 
A) any object made from dark matter 
B) a compact mass that emits no visible light 
C) an object with gravity so strong that not even light can escape 
D) a dead star that has faded from view

Question 7

Briefly describe how a nova event occurs.

Accepted Answer

A white dwarf in a close binary system a

Question 8

A typical neutron star is more massive than our Sun and about the size (radius)of .

Accepted Answer

A) Jupiter 
B) Earth 
C) the Moon 
D) a small asteroid (10 km in diameter) 
A) Jupiter 
B) Earth 
C) the Moon 
D) a small asteroid (10 km in diameter)

Question 9

The more massive a white dwarf, the _.

Accepted Answer

A) larger its radius 
B) higher its luminosity 
C) smaller its radius 
D) higher its temperature 
A) larger its radius 
B) higher its luminosity 
C) smaller its radius 
D) higher its temperature

Question 10

Imagine what would happen if Jupiter were suddenly replaced by a black hole with the same mass as Jupiter.

Accepted Answer

A) The entire solar system would instantly be sucked into the black hole. 
B) The other planets and the Sun would slowly be pulled into Jupiter. 
C) The other planets would slowly be pulled into Jupiter, but the Sun would be unaffected. 
D) The orbits of the solar system would be unaffected (including Jupiter's). 
A) The entire solar system would instantly be sucked into the black hole. 
B) The other planets and the Sun would slowly be pulled into Jupiter. 
C) The other planets would slowly be pulled into Jupiter, but the Sun would be unaffected. 
D) The orbits of the solar system would be unaffected (including Jupiter's).

Question 11

Which of the following hypothetical observations would contradict our theories about the formation and evolution of white dwarfs?

Accepted Answer

A) discovery of a white dwarf with a 1.5 Msun mass main- sequence companion 
B) discovery of a white dwarf at the center of a planetary nebula 
C) discovery of a white dwarf with a mass 1.5 times that of the Sun (1.5 Msun) 
D) discovery of a white dwarf with a surface temperature of 6000 K 
A) discovery of a white dwarf with a 1.5 Msun mass main- sequence companion 
B) discovery of a white dwarf at the center of a planetary nebula 
C) discovery of a white dwarf with a mass 1.5 times that of the Sun (1.5 Msun) 
D) discovery of a white dwarf with a surface temperature of 6000 K

Question 12

The remnant left behind by a white- dwarf supernova is a neutron star.

Accepted Answer

A) True 
 B)False

Question 13

What do we mean by the event horizon of a black hole?

Accepted Answer

A) It is the very center of the black hole. 
B) It is the distance from the black hole at which stable orbits are possible. 
C) It is the place where X- rays are emitted from black holes. 
D) It is the point beyond which neither light nor anything else can escape. 
A) It is the very center of the black hole. 
B) It is the distance from the black hole at which stable orbits are possible. 
C) It is the place where X- rays are emitted from black holes. 
D) It is the point beyond which neither light nor anything else can escape.

Question 14

Which of the following is not true about differences between novae and supernovae?

Accepted Answer

A) Supernovae eject gas into space, but novae do not. 
B) The same star can undergo novae explosions more than once, but can undergo only a single supernova. 
C) Novae are much less luminous than supernovae. 
D) Novae occur only in binary star systems, while supernovae can occur both among single stars and among binary star systems. 
A) Supernovae eject gas into space, but novae do not. 
B) The same star can undergo novae explosions more than once, but can undergo only a single supernova. 
C) Novae are much less luminous than supernovae. 
D) Novae occur only in binary star systems, while supernovae can occur both among single stars and among binary star systems.

Question 15

The surface of the neutron star RXJ2015 has a temperature of 10 million K. This neutron star glows most strongly in

Accepted Answer

A) infrared light. 
B) X- ray light. 
C) emission lines. 
D) radio light. 
E) visible light. 
A) infrared light. 
B) X- ray light. 
C) emission lines. 
D) radio light. 
E) visible light.

Question 16

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

Question 17

What is the upper limit to the mass of a white dwarf?

Accepted Answer

A) There is no upper limit. 
B) There is an upper limit, but we do not yet know what it is. 
C) 1)4 solar masses 
D) 2 solar masses 
E) 1 solar mass 
A) There is no upper limit. 
B) There is an upper limit, but we do not yet know what it is. 
C) 1)4 solar masses 
D) 2 solar masses 
E) 1 solar mass

Question 18

Which stars are more common?

Accepted Answer

A) White dwarfs and neutron stars are about equally common. 
B) black holes 
C) Neutron stars and black holes are about equally common. 
D) neutron stars 
E) white dwarfs 
A) White dwarfs and neutron stars are about equally common. 
B) black holes 
C) Neutron stars and black holes are about equally common. 
D) neutron stars 
E) white dwarfs

Question 19

Why is there an upper limit to the mass of a white dwarf?

Accepted Answer

A) The upper limit to the masses of white dwarfs was determined through observations of white dwarfs in binary systems, but no one knows why the limit exists. 
B) The more massive the white dwarf, the greater the degeneracy pressure and the faster the speeds of its electrons. Near 1.4 solar masses, the speeds of the electrons approach the speed of light, and no more mass can be supported. 
C) White dwarfs come only from stars with masses less than 1.4 solar masses. 
D) The more massive the white dwarf, the higher its temperature and hence the greater its degeneracy pressure. Near 1.4 solar masses, the temperature becomes so high that all matter effectively melts into subatomic particles. 
A) The upper limit to the masses of white dwarfs was determined through observations of white dwarfs in binary systems, but no one knows why the limit exists. 
B) The more massive the white dwarf, the greater the degeneracy pressure and the faster the speeds of its electrons. Near 1.4 solar masses, the speeds of the electrons approach the speed of light, and no more mass can be supported. 
C) White dwarfs come only from stars with masses less than 1.4 solar masses. 
D) The more massive the white dwarf, the higher its temperature and hence the greater its degeneracy pressure. Near 1.4 solar masses, the temperature becomes so high that all matter effectively melts into subatomic particles.

Question 20

Why would the earth's orbit be unaffected were the Sun to suddenly become a black hole?

Accepted Answer

The earth's orbit (and those of the othe

If you were to come back to our Solar System in 6 billion years, what might you expect to find?

The white dwarf that remains when our Sun dies will be mostly made of .

Which statement about pulsars is not thought to be true?

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

Explain why black holes in binary systems are associated with strong, steady X- ray emission.

What is the basic definition of a black hole?

Briefly describe how a nova event occurs.

A typical neutron star is more massive than our Sun and about the size (radius)of .

The more massive a white dwarf, the _.

Imagine what would happen if Jupiter were suddenly replaced by a black hole with the same mass as Jupiter.

Which of the following hypothetical observations would contradict our theories about the formation and evolution of white dwarfs?

The remnant left behind by a white- dwarf supernova is a neutron star.

What do we mean by the event horizon of a black hole?

Which of the following is not true about differences between novae and supernovae?

The surface of the neutron star RXJ2015 has a temperature of 10 million K. This neutron star glows most strongly in

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?

What is the upper limit to the mass of a white dwarf?

Which stars are more common?

Why is there an upper limit to the mass of a white dwarf?

Why would the earth's orbit be unaffected were the Sun to suddenly become a black hole?

A Modern View of 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 the Solar System

Earth and the Terrestrial Worlds

Jovian Planet System

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

Other Planetary Systems: the New Science of Distant Worlds

Our Star

Surveying the Stars

Star Stuff

Our Galaxy

A Universe of Galaxies

The Birth of the Universe

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

Life in the Universe

Filters

Exam 14: The Bizarre Stellar Graveyard

If you were to come back to our Solar System in 6 billion years, what might you expect to find?

The white dwarf that remains when our Sun dies will be mostly made of .

Which statement about pulsars is not thought to be true?

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

Explain why black holes in binary systems are associated with strong, steady X- ray emission.

What is the basic definition of a black hole?

Briefly describe how a nova event occurs.

A typical neutron star is more massive than our Sun and about the size (radius)of .

The more massive a white dwarf, the _.

Imagine what would happen if Jupiter were suddenly replaced by a black hole with the same mass as Jupiter.

Which of the following hypothetical observations would contradict our theories about the formation and evolution of white dwarfs?

The remnant left behind by a white- dwarf supernova is a neutron star.

What do we mean by the event horizon of a black hole?

Which of the following is not true about differences between novae and supernovae?

The surface of the neutron star RXJ2015 has a temperature of 10 million K. This neutron star glows most strongly in

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?

What is the upper limit to the mass of a white dwarf?

Which stars are more common?

Why is there an upper limit to the mass of a white dwarf?

Why would the earth's orbit be unaffected were the Sun to suddenly become a black hole?

A Modern View of 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 the Solar System

Earth and the Terrestrial Worlds

Jovian Planet System

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

Other Planetary Systems: the New Science of Distant Worlds

Our Star

Surveying the Stars

Star Stuff

Our Galaxy

A Universe of Galaxies

The Birth of the Universe

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

Life in the Universe

Filters