Question 1

In the model that astronomers have developed for pulsars, why do they suggest that there must be two beams of energy coming from the pulsar?

Accepted Answer

A)  because neutron stars are always surrounded by two moons (satellite bodies) 
B)  because neutron star beams come out of the north and south poles of a magnetic field 
C)  because pulsars always come in pairs 
D)  because pulsars represent supernova explosions that come out in opposite directions (but not every direction) when a massive star dies 
E)  this is an unsolved mystery in astronomy; no one has any good suggestions 
A)  because neutron stars are always surrounded by two moons (satellite bodies) 
B)  because neutron star beams come out of the north and south poles of a magnetic field 
C)  because pulsars always come in pairs 
D)  because pulsars represent supernova explosions that come out in opposite directions (but not every direction) when a massive star dies 
E)  this is an unsolved mystery in astronomy; no one has any good suggestions B

Question 2

Which of the following stages can only occur in the life of a low-mass star (whose final mass is less than 1.4 times the mass of the Sun)?

Accepted Answer

A)  proto-star 
B)  main-sequence 
C)  red giant 
D)  white dwarf 
E)  supernova 
A)  proto-star 
B)  main-sequence 
C)  red giant 
D)  white dwarf 
E)  supernova D

Question 3

Which of the following statements about Supernova 1987A is FALSE?

Accepted Answer

A)  it exploded relatively close to us, in a spiral arm of the Milky Way Galaxy 
B)  it was only visible from the Southern Hemisphere of the Earth 
C)  astronomers believe it was the explosion of a star that was originally a massive type O 
D)  neutrinos from the explosion were actually detected on Earth 
E)  it was observed with instruments in space as well as on the ground 
A)  it exploded relatively close to us, in a spiral arm of the Milky Way Galaxy 
B)  it was only visible from the Southern Hemisphere of the Earth 
C)  astronomers believe it was the explosion of a star that was originally a massive type O 
D)  neutrinos from the explosion were actually detected on Earth 
E)  it was observed with instruments in space as well as on the ground A

Question 4

A member of the college football team wants to weigh as much as possible. Assuming he could somehow survive on all of them, at the surface of which object would he weigh the most?

Accepted Answer

A)  an O-type star in the main sequence stage of its life 
B)  an M-type star in the main sequence stage of its life 
C)  a white dwarf 
D)  a neutron star 
E)  you can't fool me, his weight would be the same on all of the above objects
Section 23.5: The Evolution of Binary Star Systems 
A)  an O-type star in the main sequence stage of its life 
B)  an M-type star in the main sequence stage of its life 
C)  a white dwarf 
D)  a neutron star 
E)  you can't fool me, his weight would be the same on all of the above objects
Section 23.5: The Evolution of Binary Star Systems

Question 5

A type Ia supernova involves the transfer of mass from one star to a companion white dwarf? Yet, in some cases, astronomers cannot locate a star near where they see Type Ia explosions. How do they explain the absence of a companion star?

Accepted Answer

A)  they suggest that the companion star is a black hole 
B)  they suggest that the companion star is always of such low mass, it's easy to miss 
C)  they suggest that some type Ia supernova are caused by the collision of two white dwarfs, both of which then explode 
D)  they suggest that some type Ia supernova explosions come from a single massive star where the fusion of iron causes a catastrophe and great release of neutrinos 
E)  no one has any idea how to explain type Ia supernovae which do not leave behind a companion star; it's an unsolved mystery 
A)  they suggest that the companion star is a black hole 
B)  they suggest that the companion star is always of such low mass, it's easy to miss 
C)  they suggest that some type Ia supernova are caused by the collision of two white dwarfs, both of which then explode 
D)  they suggest that some type Ia supernova explosions come from a single massive star where the fusion of iron causes a catastrophe and great release of neutrinos 
E)  no one has any idea how to explain type Ia supernovae which do not leave behind a companion star; it's an unsolved mystery

Question 6

If observations of supernovae in other galaxies show that such an explosion happens in a spiral galaxy like the Milky Way on average every 25 to 100 years, why have astronomers on Earth not seen a supernova explosion in our Galaxy since 1604?

Accepted Answer

A)  we have been very unlucky; there have been far fewer explosions than average recently 
B)  all the explosions happened in that part of the sky which is only visible from the Earth's southern hemisphere, and we do not have any large telescopes down there 
C)  the disk of our Galaxy contains a great deal of dust, which tends to block the light of supernova explosions from more distant parts of our Galaxy 
D)  most supernova explosions produce only high-energy gamma-rays and very little light 
E)  actually, there have been supernova explosions observed, but there is a government conspiracy to keep ordinary citizens from learning about them (just like the alien creatures that were in Roswell, New Mexico and Area 51) 
A)  we have been very unlucky; there have been far fewer explosions than average recently 
B)  all the explosions happened in that part of the sky which is only visible from the Earth's southern hemisphere, and we do not have any large telescopes down there 
C)  the disk of our Galaxy contains a great deal of dust, which tends to block the light of supernova explosions from more distant parts of our Galaxy 
D)  most supernova explosions produce only high-energy gamma-rays and very little light 
E)  actually, there have been supernova explosions observed, but there is a government conspiracy to keep ordinary citizens from learning about them (just like the alien creatures that were in Roswell, New Mexico and Area 51)

Question 7

Astronomers have discovered pulsars spinning 500 x per second or more. How do astronomers think pulsars got to be spinning so outrageously fast?

Accepted Answer

A)  Because the neutron stars that are the pulsars were small when they were born, all pulsars should be spinning this fast or faster 
B)  Such fast-spinning pulsars have companion stars near them, which dump material on the pulsar and that spins it faster and faster 
C)  Pulsars are planets very close to their stars, and they have to spin so fast so they don't fall in 
D)  Such pulsars were thrown out of their original location because the supernova explosion that produced them was not the same energy in all directions; this being pushed to one side made them spin faster 
E)  Astronomers have no suggestion for why such fast-spinning pulsars exist
Section 23.6: They Mystery of the Gamma-ray Bursts 
A)  Because the neutron stars that are the pulsars were small when they were born, all pulsars should be spinning this fast or faster 
B)  Such fast-spinning pulsars have companion stars near them, which dump material on the pulsar and that spins it faster and faster 
C)  Pulsars are planets very close to their stars, and they have to spin so fast so they don't fall in 
D)  Such pulsars were thrown out of their original location because the supernova explosion that produced them was not the same energy in all directions; this being pushed to one side made them spin faster 
E)  Astronomers have no suggestion for why such fast-spinning pulsars exist
Section 23.6: They Mystery of the Gamma-ray Bursts

Question 8

Which of the following statements about the Crab Nebula is FALSE?

Accepted Answer

A)  it is the remnant of a supernova explosion first seen on Earth in 1054 AD 
B)  the nebula still puts out more energy (at all wavelengths) than 100,000 Suns 
C)  inside, there are a number of newly formed massive stars (O and B type stars) 
D)  the neutron star inside shows clear evidence of slowing down just a little bit in its rotation 
E)  we can detect a pulsar inside the nebula using both radio waves and visible light 
A)  it is the remnant of a supernova explosion first seen on Earth in 1054 AD 
B)  the nebula still puts out more energy (at all wavelengths) than 100,000 Suns 
C)  inside, there are a number of newly formed massive stars (O and B type stars) 
D)  the neutron star inside shows clear evidence of slowing down just a little bit in its rotation 
E)  we can detect a pulsar inside the nebula using both radio waves and visible light

Question 9

Astronomers observe a young cluster of stars, where stars with three times the mass of the Sun are still on the main sequence of the H-R diagram. Yet the cluster contains two white dwarfs, each with a mass less than 1.4 times the mass of the Sun. If we can show that the white dwarfs are definitely part of the cluster, how can their presence so soon in the life of the cluster be explained?

Accepted Answer

A)  the lower the mass of a star, the more quickly it goes through each stage of its life 
B)  white dwarfs are what is left over after a star explodes and throws off 90% of its mass 
C)  some stars can lose a lot of mass on their way to becoming white dwarfs; thus the white dwarfs could have started out as quite massive stars 
D)  stars less massive than 1.4 times the mass of the Sun go through the white dwarf stage in their lives before they become main sequence stars 
E)  astronomers can think of no way to explain this problem; it has them completely baffled 
A)  the lower the mass of a star, the more quickly it goes through each stage of its life 
B)  white dwarfs are what is left over after a star explodes and throws off 90% of its mass 
C)  some stars can lose a lot of mass on their way to becoming white dwarfs; thus the white dwarfs could have started out as quite massive stars 
D)  stars less massive than 1.4 times the mass of the Sun go through the white dwarf stage in their lives before they become main sequence stars 
E)  astronomers can think of no way to explain this problem; it has them completely baffled

Question 10

Astronomers have long realized that supernovae -- when they explode -- give off an enormous amount of light. But observations of Supernova 1987A (in the Large Magellanic Cloud) revealed that the supernova gives off even more energy in another form? That form is:

Accepted Answer

A)  radio waves 
B)  WIMPS 
C)  dark matter 
D)  sound 
E)  neutrinos 
A)  radio waves 
B)  WIMPS 
C)  dark matter 
D)  sound 
E)  neutrinos

Question 11

Which of the following is one reason we do not detect a pulsar in many remnants of supernova explosions?

Accepted Answer

A)  most stars (our own Sun, for example) don't rotate at all, so no pulsar can form 
B)  the radiation with which we detect pulsars doesn't get through the Earth's atmosphere 
C)  the pulsar beam doesn't happen to point toward us in many cases 
D)  many supernova remnants contain white dwarfs or black dwarfs 
E)  the little green men inside put shades on their pulsars for privacy 
A)  most stars (our own Sun, for example) don't rotate at all, so no pulsar can form 
B)  the radiation with which we detect pulsars doesn't get through the Earth's atmosphere 
C)  the pulsar beam doesn't happen to point toward us in many cases 
D)  many supernova remnants contain white dwarfs or black dwarfs 
E)  the little green men inside put shades on their pulsars for privacy

Question 12

What kind of telescope did Jocelyn Bell use to discover pul?sars in 1968?

Accepted Answer

A)  visible light 
B)  radio 
C)  ultraviolet 
D)  x-ray 
E)  neutr?ino 
A)  visible light 
B)  radio 
C)  ultraviolet 
D)  x-ray 
E)  neutr?ino

Question 13

Your sweetheart gives you a piece of gold jewelry as a present to celebrate your passing your astronomy class. Where did the gold atoms in that gift originally come from (where were they most likely made)?

Accepted Answer

A)  they were fused during the supergiant stage in the life of a massive star 
B)  they were built up from smaller nuclei during a supernova explosion 
C)  they were fused during the main sequence stage of a low-mass star 
D)  they were fused deep inside the hot core of the Earth a few million years ago 
E)  they were produced from other atoms in the cool outer envelopes of a red giant star 
A)  they were fused during the supergiant stage in the life of a massive star 
B)  they were built up from smaller nuclei during a supernova explosion 
C)  they were fused during the main sequence stage of a low-mass star 
D)  they were fused deep inside the hot core of the Earth a few million years ago 
E)  they were produced from other atoms in the cool outer envelopes of a red giant star

Question 14

A charming friend of yours who has been reading a little bit about astronomy accompanies you to the campus observatory and asks to see the kind of star that our Sun will ultimately become, long, long after it has turned into a white dwarf. Why is the astronomer on duty going to have a bit of a problem satisfying her request?

Accepted Answer

A)  after being a white dwarf, the Sun will explode, and there will be nothing left to see 
B)  the universe is not even old enough to have produced any white dwarfs yet 
C)  all the old stars in our Galaxy are located in globular clusters and all of these are too far away to be seen with the kind of telescope a college or university campus would have 
D)  after a white dwarf cools off it becomes too cold and dark to emit visible light 
E)  astronomers only let people with PhD's look at these stellar corpses; it's like an initiation rite for those who become astronomers 
A)  after being a white dwarf, the Sun will explode, and there will be nothing left to see 
B)  the universe is not even old enough to have produced any white dwarfs yet 
C)  all the old stars in our Galaxy are located in globular clusters and all of these are too far away to be seen with the kind of telescope a college or university campus would have 
D)  after a white dwarf cools off it becomes too cold and dark to emit visible light 
E)  astronomers only let people with PhD's look at these stellar corpses; it's like an initiation rite for those who become astronomers

Question 15

Astronomer have concluded that pulsars are

Accepted Answer

A)  rotating black holes 
B)  rotating neutron stars 
C)  rotating red giants 
D)  supernovae that are about to ex?plode 
E)  protostars that are collapsing and spinning very rapidly 
A)  rotating black holes 
B)  rotating neutron stars 
C)  rotating red giants 
D)  supernovae that are about to ex?plode 
E)  protostars that are collapsing and spinning very rapidly

Question 16

A white dwarf, compared to a main sequence star with the same mass, would always be:

Accepted Answer

A)  redder in color 
B)  smaller in diameter 
C)  the same size 
D)  younger in age 
E)  more massive 
A)  redder in color 
B)  smaller in diameter 
C)  the same size 
D)  younger in age 
E)  more massive

Question 17

Although centuries ago, astronomers thought that a nova was a new star, appearing for the first time in the heavens, today we know that it is:

Accepted Answer

A)  a binary star system in which one star is a white dwarf and mass is being transferred to it 
B)  the explosion of a massive star when the fusion of iron leads to the collapse of its core 
C)  the brightening of a neutron star when it becomes a pulsar 
D)  the emission of a bright planetary nebula late in a star's life 
E)  the birth of a high-mass protostar in a giant molecular cloud 
A)  a binary star system in which one star is a white dwarf and mass is being transferred to it 
B)  the explosion of a massive star when the fusion of iron leads to the collapse of its core 
C)  the brightening of a neutron star when it becomes a pulsar 
D)  the emission of a bright planetary nebula late in a star's life 
E)  the birth of a high-mass protostar in a giant molecular cloud

Question 18

Which of the following is NOT a result of supernova explosions?

Accepted Answer

A)  many of the elements the star fused during its life are blasted out into space 
B)  new heavier elements (including such heavy nuclei lead and uranium) are fused by neutron bombardment during the explosion 
C)  a tremendous flood of high-energy cosmic ray particles is released 
D)  any planets within a few dozen LY of the explosion are bathed with life-threatening radiation 
E)  the neutron star is disrupted and tears apart into many pieces 
A)  many of the elements the star fused during its life are blasted out into space 
B)  new heavier elements (including such heavy nuclei lead and uranium) are fused by neutron bombardment during the explosion 
C)  a tremendous flood of high-energy cosmic ray particles is released 
D)  any planets within a few dozen LY of the explosion are bathed with life-threatening radiation 
E)  the neutron star is disrupted and tears apart into many pieces

Question 19

When a single star with a mass equal to the Sun dies, it will become a

Accepted Answer

A)  white dwarf 
B)  neutron star 
C)  black hole 
D)  pulsar 
E)  burster 
A)  white dwarf 
B)  neutron star 
C)  black hole 
D)  pulsar 
E)  burster

Question 20

In a supernova like SN1987A, once the crisis of iron fusion has begun, roughly how long does it take the star's core to collapse?

Accepted Answer

A)  10 million years 
B)  10 thousand years 
C)  a hundred years 
D)  one year 
E)  a few tenths of a second 
A)  10 million years 
B)  10 thousand years 
C)  a hundred years 
D)  one year 
E)  a few tenths of a second

Exam 23: The Death of Stars

In the model that astronomers have developed for pulsars, why do they suggest that there must be two beams of energy coming from the pulsar?

Which of the following stages can only occur in the life of a low-mass star (whose final mass is less than 1.4 times the mass of the Sun)?

Which of the following statements about Supernova 1987A is FALSE?

A member of the college football team wants to weigh as much as possible. Assuming he could somehow survive on all of them, at the surface of which object would he weigh the most?

A type Ia supernova involves the transfer of mass from one star to a companion white dwarf? Yet, in some cases, astronomers cannot locate a star near where they see Type Ia explosions. How do they explain the absence of a companion star?

If observations of supernovae in other galaxies show that such an explosion happens in a spiral galaxy like the Milky Way on average every 25 to 100 years, why have astronomers on Earth not seen a supernova explosion in our Galaxy since 1604?

Astronomers have discovered pulsars spinning 500 x per second or more. How do astronomers think pulsars got to be spinning so outrageously fast?

Which of the following statements about the Crab Nebula is FALSE?

Astronomers have long realized that supernovae -- when they explode -- give off an enormous amount of light. But observations of Supernova 1987A (in the Large Magellanic Cloud) revealed that the supernova gives off even more energy in another form? That form is:

Which of the following is one reason we do not detect a pulsar in many remnants of supernova explosions?

What kind of telescope did Jocelyn Bell use to discover pul?sars in 1968?

Your sweetheart gives you a piece of gold jewelry as a present to celebrate your passing your astronomy class. Where did the gold atoms in that gift originally come from (where were they most likely made)?

Astronomer have concluded that pulsars are

A white dwarf, compared to a main sequence star with the same mass, would always be:

Although centuries ago, astronomers thought that a nova was a new star, appearing for the first time in the heavens, today we know that it is:

Which of the following is NOT a result of supernova explosions?

When a single star with a mass equal to the Sun dies, it will become a

In a supernova like SN1987A, once the crisis of iron fusion has begun, roughly how long does it take the star's core to collapse?

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