CAS AS 101 Chapter Notes - Chapter 8: Radioactive Decay, Solar Rotation, Flattening
8 Sep 2016
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Document Summary
Several reasonable hypotheses were explored: nebular hypothesis, close encounter hypothesis. Nebular theory: our solar system formed from the gravitational collapse of a giant interstellar gas. Close encounter hypothesis: a rival idea proposed that the planets formed from debris torn off the sun by a close encounter with another star. That hypothesis could not explain observed motions and types of planets. If the sun were ripped, the movement of the planets would be more random cloud the solar nebula. Kant and laplace proposed the nebular hypothesis over two centuries ago. A large amount of evidence now supports this idea. Galactic recycling: elements that formed planets were made in stars and then recycled through interstellar space. Evidence from other gas clouds: we can see stars forming in other interstellar gas clouds, lending support to the nebula theory. Observations of disks around other stars support the nebular hypothesis.
