A) accreting white dwarfs
B) rapidly rotating neutron stars
C) unstable high-mass stars
D) accreting black holes
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A) We now know that gamma-ray bursts come not from neutron stars but from black holes.
B) Theoretical work has proven that gamma rays cannot be produced in accretion disks.
C) Observations from the Compton Gamma-Ray Observatory showed that gamma-ray bursts come randomly from all directions in the sky.
D) Observations from the Compton Gamma-Ray Observatory showed that gamma-ray bursts occur too frequently to be attributed to neutron stars.
E) Observations from the Compton Gamma-Ray Observatory allowed us to trace gamma-ray bursts to pulsating variable stars in distant galaxies.
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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.
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A) The entire mass of the Earth would end up as a thin layer, about 1 cm thick, over the surface of the neutron star.
B) It would rapidly sink to the center of the Earth.
C) The combined mass of the Earth and the neutron star would cause the neutron star to collapse into a black hole.
D) It would crash through the Earth, creating a large crater, and exit the Earth on the other side.
E) It would crash into the Earth, throwing vast amounts of dust into the atmosphere which in turn would cool the Earth. Such a scenario is probably what caused the extinction of the dinosaurs.
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A) Pulsars are easy to identify by their almost perfectly steady periods of pulsation.
B) Pulsars are very bright and therefore easy to find.
C) Several pulsars are located within a dozen light-years of our solar system, making them useful for finding our solar system.
D) We're pretty sure that aliens will have only radio telescopes and not optical telescopes, so they'll have a better chance of seeing pulsars than ordinary stars.
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A) white dwarf
B) neutron star
C) black hole
D) none of the above
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A) Supernovae eject gas into space but novae do not.
B) Novae are much less luminous than supernovae.
C) Novae occur only in binary star systems, while supernovae can occur both among single stars and among binary star systems.
D) The same star can undergo novae explosions more than once, but can undergo only a single supernova.
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A) Based on their distribution in the sky, we can rule out a connection between gamma ray bursts and X-ray binaries in the Milky Way Galaxy.
B) Gamma ray bursts are among the most luminous events that ever occur in the universe.
C) The events responsible for gamma ray bursts apparently produce only gamma rays, and no other light that we can hope to detect.
D) Gamma ray bursts were originally discovered by satellites designed to look for signs of nuclear bomb tests on Earth.
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A) Main sequence star, white dwarf, neutron star, black hole singularity
B) Main sequence star, black hole singularity, neutron star, white dwarf
C) Main sequence star, neutron star, white dwarf, black hole singularity
D) Black hole singularity, main sequence star, white dwarf, neutron star
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A) X-rays from the accretion disk
B) Tidal forces due to the black hole
C) The crush of gravity at the singularity embedded within the black hole
D) The sucking force from the black hole, which will cause his head to explode
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A) about the same as a regular paperclip.
B) a few tons.
C) more than Mt. Everest.
D) more than the Moon.
E) more than the Earth.
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A) the Earth
B) a city
C) a football stadium
D) a basketball
E) the Sun
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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 hole
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A) what most stars become when they die
B) a precursor to a black hole
C) an early stage of a neutron star
D) a brown dwarf that has exhausted its fuel for nuclear fusion
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A) A star system that undergoes a nova may have another nova sometime in the future.
B) A nova involves fusion taking place on the surface of a white dwarf.
C) Our Sun will probably undergo at least one nova when it becomes a white dwarf about 5 billion years from now.
D) When a star system undergoes a nova, it brightens considerably, but not as much as a star system undergoing a supernova.
E) The word nova means "new star" and originally referred to stars that suddenly appeared in the sky, then disappeared again after a few weeks or months.
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A) The other planets would slowly be pulled into Jupiter, but the Sun would be unaffected.
B) The orbits of the solar system would be unaffected (including Jupiter's)
C) The entire solar system would instantly be sucked into the black hole.
D) The other planets and the Sun would slowly be pulled into Jupiter.
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