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Water and Water Ice
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Weather and Atmospheric Phenomena
The layers of gas that are gravitationally bound above the surface of a planet, moon, or outer layers of a star.
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Whirlpool Galaxy, M51
A beautiful galaxy about 30 million light-years away, in the constellation Canes Venatici.
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White Dwarfs
The hot, dense cores of once-normal stars like the Sun. At the end of such a star’s life, it can no longer produce the nuclear-fusion reactions that power it. Its outer layers drift away into space, while its core collapses into a ball that is as about as massive as the Sun but no bigger than Earth. This is the fate of stars that do not exceed about four to eight times the mass of the Sun. The Sun reaches this stage in a few hundred million to several billion years, depending on the star’s original mass. A white dwarf may spin rapidly, is extremely hot, and may generate a strong magnetic field.
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World War II
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Wormholes
A theoretical “shortcut” between two points in space-time made possible by a singularity. In science fiction, wormholes allow people and starships to travel from one part of the galaxy to another almost instantaneously. While theory allows wormholes to exist, they would make poor passageways because they should close up as soon as anything tries to enter them.