Question 1

What incident in a massive star's life sets off (begins) the very quick chain of events that leads to a supernova explosion?

Accepted Answer

A)  swelling up to become a red giant 
B)  the fusion of iron 
C)  helium begins to fuse into carbon 
D)  an event horizon forms 
E)  the star's core becomes degenerate and the electrons don't allow further compression 
A)  swelling up to become a red giant 
B)  the fusion of iron 
C)  helium begins to fuse into carbon 
D)  an event horizon forms 
E)  the star's core becomes degenerate and the electrons don't allow further compression

Question 2

Which of the following statements about the life of a star with a mass like the Sun is correct?

Accepted Answer

A)  before the star dies, it will fuse dozens of elements in its core 
B)  as the star is dying, a considerable part of its mass will be lost into space 
C)  after the main sequence stage, there is no further fusion of hydrogen anywhere in the star 
D)  at the end of its life, the star will explode as a supernova 
E)  the core of this star will be too massive to form a white dwarf 
A)  before the star dies, it will fuse dozens of elements in its core 
B)  as the star is dying, a considerable part of its mass will be lost into space 
C)  after the main sequence stage, there is no further fusion of hydrogen anywhere in the star 
D)  at the end of its life, the star will explode as a supernova 
E)  the core of this star will be too massive to form a white dwarf

Question 3

Which of the following statements about our best candidate for long-duration gamma-ray bursts is FALSE?

Accepted Answer

A)  it involves the merger of two black holes 
B)  most of the bursts it causes can be shown to be in distant galaxies 
C)  the bursts it produces are more frequently seen and are brighter and easier to pinpoint 
D)  the mechanism involves a special type of supernova explosion 
E)  a rotating, magnetic star corpse most likely produces jets (or beams) 
A)  it involves the merger of two black holes 
B)  most of the bursts it causes can be shown to be in distant galaxies 
C)  the bursts it produces are more frequently seen and are brighter and easier to pinpoint 
D)  the mechanism involves a special type of supernova explosion 
E)  a rotating, magnetic star corpse most likely produces jets (or beams)

Question 4

Which of the following statements about a Type II Supernova is true?

Accepted Answer

A)  Type II supernovas happen when a white dwarf is overloaded with mass from a companion star 
B)  Type II supernovas occur in the Milky Way Galaxy just about every year. It's rare to have a year without one happening in the Galaxy. 
C)  A Type II supernova is so faint that we miss most of the ones that happen in our Galaxy 
D)  A Type II supernova occurs at the end of the life of a star with 10 times the mass of our Sun or more 
E)  A Type II supernova is a less powerful explosion than any other type; it can't make any of the elements heavier than iron 
A)  Type II supernovas happen when a white dwarf is overloaded with mass from a companion star 
B)  Type II supernovas occur in the Milky Way Galaxy just about every year. It's rare to have a year without one happening in the Galaxy. 
C)  A Type II supernova is so faint that we miss most of the ones that happen in our Galaxy 
D)  A Type II supernova occurs at the end of the life of a star with 10 times the mass of our Sun or more 
E)  A Type II supernova is a less powerful explosion than any other type; it can't make any of the elements heavier than iron

Question 5

When a star undergoes a nova explosion, it may return to its "quiet state" and later become a nova again. What would allow a nova explosion to happen to a star more than once?

Accepted Answer

A)  the star that goes nova collides with several stars in a star cluster 
B)  the star that goes nova has a companion star near it, which dumps material onto the first star and continues to do so even after the first nova explosion 
C)  the star that goes nova has a number of massive planets around it which fall in 
D)  the star that goes nova has an iron catastrophe in its core and then another step in the fusion of heavy elements producer another explosion 
E)  a nova explosion happens each time a neutron star rotates to face us, and that happens every century or so 
A)  the star that goes nova collides with several stars in a star cluster 
B)  the star that goes nova has a companion star near it, which dumps material onto the first star and continues to do so even after the first nova explosion 
C)  the star that goes nova has a number of massive planets around it which fall in 
D)  the star that goes nova has an iron catastrophe in its core and then another step in the fusion of heavy elements producer another explosion 
E)  a nova explosion happens each time a neutron star rotates to face us, and that happens every century or so

Question 6

The most stable (tightly bound) atomic nucleus in the universe is:

Accepted Answer

A)  hydrogen 
B)  carbon 
C)  uranium 
D)  technetium 
E)  iron 
A)  hydrogen 
B)  carbon 
C)  uranium 
D)  technetium 
E)  iron

Question 7

After the core of a massive star becomes a neutron star, the rest of the star's material

Accepted Answer

A)  falls inward very slowly, taking billions of years to get really compressed 
B)  makes a planetary nebula, which gently moves outward from the center 
C)  is vaporized by the incredible heat of the dying star and evaporates 
D)  explodes outward as a supernova 
E)  continues regular fusion and returns to the main sequence 
A)  falls inward very slowly, taking billions of years to get really compressed 
B)  makes a planetary nebula, which gently moves outward from the center 
C)  is vaporized by the incredible heat of the dying star and evaporates 
D)  explodes outward as a supernova 
E)  continues regular fusion and returns to the main sequence

Question 8

Which of the following is a characteristic of degenerate matter in a white dwarf star?

Accepted Answer

A)  helium is actively fusing into carbon 
B)  electrons and protons join together in the nucleus to make neutrons and neutrinos 
C)  the degenerate matter region is expanding as time passes, until it covers a region the size of the orbit of Mars 
D)  the electrons get as close to each other as possible and resist further compression 
E)  the atoms drink, smoke, use bad language, and are attracted to the wrong kinds of particles 
A)  helium is actively fusing into carbon 
B)  electrons and protons join together in the nucleus to make neutrons and neutrinos 
C)  the degenerate matter region is expanding as time passes, until it covers a region the size of the orbit of Mars 
D)  the electrons get as close to each other as possible and resist further compression 
E)  the atoms drink, smoke, use bad language, and are attracted to the wrong kinds of particles

Question 9

When neutron stars were first predicted theoretically, no scientist expected to be able to detect one of them across interstellar distances. What enabled astronomers to find neutron stars in the late 1960's?

Accepted Answer

A)  they give off a lot more light than expected, and can be seen glowing with a reddish light from far away 
B)  they are so large, their dark outline block a significant amount of starlight from behind them 
C)  we found strongly magnetic neutron stars whose whirling beams of energy were detected as pulsars 
D)  some neutron stars soon collapse to be white dwarfs, whose light can be detected further away 
E)  astronomers have actually only found one neutron star and that was discovered very close to us and by sheer luck 
A)  they give off a lot more light than expected, and can be seen glowing with a reddish light from far away 
B)  they are so large, their dark outline block a significant amount of starlight from behind them 
C)  we found strongly magnetic neutron stars whose whirling beams of energy were detected as pulsars 
D)  some neutron stars soon collapse to be white dwarfs, whose light can be detected further away 
E)  astronomers have actually only found one neutron star and that was discovered very close to us and by sheer luck

Question 10

Astronomers have noticed that the visible filaments in the Crab Nebula are moving toward us at great speed. How can they know about motions like this?

Accepted Answer

A)  from the width of the pulsar pulses 
B)  from the color of the nebula's continuous radiation 
C)  from the spacing of the pulsar pulses 
D)  from the H-R diagram 
E)  from the Doppler shift in the line radiation from the nebula 
A)  from the width of the pulsar pulses 
B)  from the color of the nebula's continuous radiation 
C)  from the spacing of the pulsar pulses 
D)  from the H-R diagram 
E)  from the Doppler shift in the line radiation from the nebula

Question 11

In a collapsing star of high mass, when electrons and protons are squeezed together with enormous force, they turn into a neutron and a:

Accepted Answer

A)  positron 
B)  helium nucleus 
C)  neutrino 
D)  radio wave 
E)  nucleus of iron 
A)  positron 
B)  helium nucleus 
C)  neutrino 
D)  radio wave 
E)  nucleus of iron

Question 12

Some of the energy produced in the event we call Supernova 1987A was used to blow the star apart. Out of the following places that the energy of this event could go, which absorbed by far the most energy?

Accepted Answer

A)  the production of huge numbers of neutrinos 
B)  the movement of the outer layers of the star in an outward direction 
C)  the production of visible light (which could be seen with the naked eye from Earth) 
D)  the production of gamma rays 
E)  all of the above took roughly the same amount of energy - the energy was pretty evenly divided among them
Section 23.4: Pulsars and the Discovery of Neutron Stars 
A)  the production of huge numbers of neutrinos 
B)  the movement of the outer layers of the star in an outward direction 
C)  the production of visible light (which could be seen with the naked eye from Earth) 
D)  the production of gamma rays 
E)  all of the above took roughly the same amount of energy - the energy was pretty evenly divided among them
Section 23.4: Pulsars and the Discovery of Neutron Stars

Question 13

A rich donor to your college gets fascinated by gamma-ray bursts, and wants to give money to find out more about what produces them. Which of the following should her money go to fund?

Accepted Answer

A)  a radio telescope, sensitive to the radiation given off by cold hydrogen 
B)  a gamma-ray telescope located on your campus, operated by graduate students 
C)  a network of visible-light telescopes which can automatically swing to a location provided by an alert system at NASA 
D)  a large infra-red telescope that is good at finding asteroids and comets at the outskirts of our solar system 
E)  the donor is too late; all the sources of gamma-ray bursts that we will ever see have already been identified 
A)  a radio telescope, sensitive to the radiation given off by cold hydrogen 
B)  a gamma-ray telescope located on your campus, operated by graduate students 
C)  a network of visible-light telescopes which can automatically swing to a location provided by an alert system at NASA 
D)  a large infra-red telescope that is good at finding asteroids and comets at the outskirts of our solar system 
E)  the donor is too late; all the sources of gamma-ray bursts that we will ever see have already been identified

Question 14

Where does the energy come from that allows the Crab Nebula to keep shining almost a 1000 years after the star exploded? (Who ultimately "pays the energy bill"?)

Accepted Answer

A)  material is still being ejected from the star in the form of a planetary nebula 
B)  a massive black hole is "eating" material at the center of the nebula 
C)  a neutron star is slowing down (losing rotation energy) 
D)  large parts of the nebula are falling inward, releasing gravi?tational energy 
E)  the Crab nebula is a signal station, where some aliens (LGM) are broad?casting beats for rap music 
A)  material is still being ejected from the star in the form of a planetary nebula 
B)  a massive black hole is "eating" material at the center of the nebula 
C)  a neutron star is slowing down (losing rotation energy) 
D)  large parts of the nebula are falling inward, releasing gravi?tational energy 
E)  the Crab nebula is a signal station, where some aliens (LGM) are broad?casting beats for rap music

Question 15

When the mass of a star's core is greater than 1.4 times the mass of the Sun, degenerate electrons can't keep it stable as a white dwarf. Instead, it becomes:

Accepted Answer

A)  a neutron star 
B)  a planetary nebula 
C)  a red giant 
D)  a ball of solid iron, with layers of other elements around it 
E)  a black dwarf 
A)  a neutron star 
B)  a planetary nebula 
C)  a red giant 
D)  a ball of solid iron, with layers of other elements around it 
E)  a black dwarf

Question 16

Which of the following stages will the Sun definitely go through as it gets older?

Accepted Answer

A)  red giant 
B)  source of a planetary nebula 
C)  white dwarf 
D)  black dwarf 
E)  all the above 
A)  red giant 
B)  source of a planetary nebula 
C)  white dwarf 
D)  black dwarf 
E)  all the above

Question 17

Astronomers now have a good idea for explaining how the short-duration gamma-ray bursts might come about. Which of the following is part of their explanation?

Accepted Answer

A)  these bursts come from the clouds of comets that surrounds our solar system 
B)  these bursts most likely come from the merger of two neutron stars 
C)  these bursts involve a supernova explosion of a star that has lost its outer layer of hydrogen 
D)  these bursts should easily be observed to have "afterglows" in other wavelengths besides gamma-rays 
E)  these bursts are very common; most of the gamma-ray bursts are short-duration 
A)  these bursts come from the clouds of comets that surrounds our solar system 
B)  these bursts most likely come from the merger of two neutron stars 
C)  these bursts involve a supernova explosion of a star that has lost its outer layer of hydrogen 
D)  these bursts should easily be observed to have "afterglows" in other wavelengths besides gamma-rays 
E)  these bursts are very common; most of the gamma-ray bursts are short-duration

Question 18

In a Type Ia supernova, the cause of the violent outburst is:

Accepted Answer

A)  the sudden emission of a shell of stellar material from a dying low-mass star 
B)  the collapse of a very massive protostar to the main sequence 
C)  an enormous release of neutrinos during a sudden episode of hydrogen fusion 
D)  the transfer of so much mass from a companion star that a white dwarf goes "over the limit" and collapses, causing an enormous amount of sudden fusion 
E)  two neutron stars colliding with each other 
A)  the sudden emission of a shell of stellar material from a dying low-mass star 
B)  the collapse of a very massive protostar to the main sequence 
C)  an enormous release of neutrinos during a sudden episode of hydrogen fusion 
D)  the transfer of so much mass from a companion star that a white dwarf goes "over the limit" and collapses, causing an enormous amount of sudden fusion 
E)  two neutron stars colliding with each other

Question 19

A star with a mass like the Sun which will soon die is observed to be surrounded by a large amount of dust and gas -- all material it has expelled in the late stages of its life. If astronomers want to observe the radiation from such a giant star surrounded by its own debris, which of the following bands of the spectrum would be the best to use to observe it?

Accepted Answer

A)  gamma-rays 
B)  x-rays 
C)  ultraviolet 
D)  infrared 
E)  very long wavelength radio waves 
A)  gamma-rays 
B)  x-rays 
C)  ultraviolet 
D)  infrared 
E)  very long wavelength radio waves

Question 20

How did observations with the Compton Gamma-ray Observatory show that gamma-ray bursts were not coming from the Milky Way Galaxy?

Accepted Answer

A)  the bursts were all so "faint" (so little energy reached us) that they must be very far away 
B)  the gamma-rays were all Doppler shifted, showing the sources were moving very fast 
C)  the gamma-rays came from all over the sky, not just the plane of the Galaxy 
D)  the gamma-rays were seen mostly from the direction of the planets in our solar system 
E)  there were so few bursts observed with the Compton Observatory that it was not possible to figure out where they were coming from 
A)  the bursts were all so "faint" (so little energy reached us) that they must be very far away 
B)  the gamma-rays were all Doppler shifted, showing the sources were moving very fast 
C)  the gamma-rays came from all over the sky, not just the plane of the Galaxy 
D)  the gamma-rays were seen mostly from the direction of the planets in our solar system 
E)  there were so few bursts observed with the Compton Observatory that it was not possible to figure out where they were coming from

Exam 23: The Death of Stars

What incident in a massive star's life sets off (begins) the very quick chain of events that leads to a supernova explosion?

Which of the following statements about the life of a star with a mass like the Sun is correct?

Which of the following statements about our best candidate for long-duration gamma-ray bursts is FALSE?

Which of the following statements about a Type II Supernova is true?

When a star undergoes a nova explosion, it may return to its "quiet state" and later become a nova again. What would allow a nova explosion to happen to a star more than once?

The most stable (tightly bound) atomic nucleus in the universe is:

After the core of a massive star becomes a neutron star, the rest of the star's material

Which of the following is a characteristic of degenerate matter in a white dwarf star?

When neutron stars were first predicted theoretically, no scientist expected to be able to detect one of them across interstellar distances. What enabled astronomers to find neutron stars in the late 1960's?

Astronomers have noticed that the visible filaments in the Crab Nebula are moving toward us at great speed. How can they know about motions like this?

In a collapsing star of high mass, when electrons and protons are squeezed together with enormous force, they turn into a neutron and a:

Some of the energy produced in the event we call Supernova 1987A was used to blow the star apart. Out of the following places that the energy of this event could go, which absorbed by far the most energy?

A rich donor to your college gets fascinated by gamma-ray bursts, and wants to give money to find out more about what produces them. Which of the following should her money go to fund?

Where does the energy come from that allows the Crab Nebula to keep shining almost a 1000 years after the star exploded? (Who ultimately "pays the energy bill"?)

When the mass of a star's core is greater than 1.4 times the mass of the Sun, degenerate electrons can't keep it stable as a white dwarf. Instead, it becomes:

Which of the following stages will the Sun definitely go through as it gets older?

Astronomers now have a good idea for explaining how the short-duration gamma-ray bursts might come about. Which of the following is part of their explanation?

In a Type Ia supernova, the cause of the violent outburst is:

How did observations with the Compton Gamma-ray Observatory show that gamma-ray bursts were not coming from the Milky Way Galaxy?

Science and the Universe: a Brief Tour

Observing the Sky: the Birth of Astronomy

Orbits and Gravity

Earth, Moon, and Sky

Radiation and Spectra

Astronomical Instruments

Other Worlds: an Introduction to the Solar System

Earth As a Planet

Cratered Worlds: the Moon and Mercury

Earthlike Planets: Venus and Mars

The Giant Planets

Rings, Moons, and Pluto

Comets and Asteroids: Debris of the Solar System

Cosmic Samples and the Origin of the Solar System

The Sun: a Garden-Variety Star

The Sun: a Nuclear Powerhouse

Analyzing Starlight

The Stars: a Celestial Census

Celestial Distances

Between the Stars

The Birth of Stars and the Discovery of Planets Outside the Solar System

Stars From Adolescence to Old Age

Black Holes and Curved Space-Time

The Milky Way Galaxy

Galaxies

Active Galaxies, Quasars, and Supermassive Black Holes

The Evolution and Distribution of Galaxies

The Big Bang

Life in the Universe

Filters