A) the red giant will probably supernova within the next million years
B) jets of material shot out of the accretion disk will shoot down their planet
C) the red giant star, which provides most of energy the civilization needs to exist, will soon be destroyed in the accretion disk
D) tidal forces from the black hole will rip the planet apart
E) the planet's orbit gradually will decay, as it is sucked in by the black hole
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A) the Moon
B) the Earth
C) Jupiter
D) the Sun
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A) a brown dwarf.
B) a white dwarf.
C) a neutron star.
D) a very massive main-sequence star.
E) the central core of the Sun after hydrogen fusion ceases but before helium fusion begins.
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A) as much as a truck
B) about 5 pounds
C) as much as the entire Earth
D) as much as an average person
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A) A spaceship passing near a 10 solar mass black hole is much more likely to be destroyed than a spaceship passing at the same distance from the center of a 10 solar mass main-sequence star.
B) Although we are not 100% certain that black holes exist, we have strong observational evidence in favor of their existence.
C) If you watch someone else fall into a black hole, you will never see him (or her) cross the event horizon; you'll only see him fade from view as the light he emits or reflects becomes more and more redshifted.
D) If you fell into a black hole, you would experience time to be running normally as you plunged rapidly across the event horizon.
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A) Intense X-ray bursts
B) Spectral lines from the companion star that alternately shift to shorter and longer wavelengths
C) Visible and ultraviolet light from the companion star
D) Bright X-ray emission that varies on a time scale of a few hours
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A
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A) about the mass of our Sun
B) about 1.4 times the mass of our Sun
C) limitless; there is no theoretical limit to the maximum mass of a white dwarf
D) about 3 times the mass of our Sun
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A) An explosion on the surface of a white dwarf in a close binary system
B) The explosion of a massive star at the end of its life
C) The sudden formation of a new star in the sky
D) A rapidly spinning neutron star
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A) smaller its radius
B) higher its temperature
C) larger its radius
D) higher its luminosity
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A) Degeneracy pressure can continue to support an object against gravitational collapse even if the object becomes extremely cold.
B) Degeneracy pressure arises from a quantum mechanical effect that we don't notice in our daily lives.
C) Black holes form when gravity overcomes neutron degeneracy pressure.
D) Degeneracy pressure can arise only from interactions among electrons.
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A) It will cool down and become a cold black dwarf.
B) As gravity overwhelms the electron degeneracy pressure, it will explode as a nova.
C) As gravity overwhelms the electron degeneracy pressure, it will explode as a supernova.
D) As gravity overwhelms the electron degeneracy pressure, it will become a neutron star.
E) The electron degeneracy pressure slowly overwhelms gravity and the white dwarf evaporates.
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A) Both involve explosions on the surface of stellar corpse.
B) Both typically recur every few hours to every few days.
C) Both are thought to involve fusion of hydrogen into helium.
D) Both result in the complete destruction of their host stars.
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A) The white dwarf will explode completely as a white dwarf supernova.
B) The white dwarf will collapse in size, becoming a neutron star.
C) The white dwarf will undergo a nova explosion.
D) The white dwarf will collapse to become a black hole.
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A) There is no upper limit.
B) There is an upper limit, but we do not yet know what it is.
C) 2 solar masses
D) 1.4 solar masses
E) 1 solar mass
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A) infrared light.
B) X-ray light.
C) radio light.
D) visible light.
E) emission lines.
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False
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A) They evolved on a different planet in a different star system, and moved to their current location.
B) As a result of traumatic experiences to their evolutionary ancestors, they dislike television.
C) Their immediate ancestors were chimpanzees.
D) They believe that the presence of two stars in their system was critical to their evolution.
E) They evolved from primitive wormlike creatures that had 13 legs, 4 eyes, and bald heads, thus explaining why such critters are now considered a spectacular delicacy.
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A
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A) It's a mystery: no one really knows.
B) It is eclipsed by a companion 30 times per second.
C) It rotates 30 times per second.
D) A jet ejects energy and particles from a hot spot 30 times per second.
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