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Descartes proposed that the solar system formed from a contracting vortex of matter.
Buffon later suggested that a passing comet pulled matter out of the sun to form the planet
Passing star hypothesis
Astronomers replaced the comet with a star from catastrophic (comet) hypothesis
Laplace's hypothesis required a contracting nebula to leave behind rings that formed each planet
Solar nebula theory
Theory proposes that the planets formed in a disk of gas and dust around the protostar that became the sun
Icy bodies that pass through the inner solar system along long elliptical orbits. As the ices vaporize and release dust, the comet develops a tail that points approximately away from the sun
Small bits of rock and metal colliding with Earth's atmosphere and bursting into incandescent vapor because of friction with the air about 80 km above the ground. Commonly called "shooting stars".
Specks of dust, grains of sand, or tiny pebbles that survive the passage to Earth's surface.
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