EAPS 10200 Lecture Notes - Lecture 1: Nuclear Weapon, Holt Tractor, Planetesimal
7 Oct 2017
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Document Summary
As the gas started to cool matter began to condense into clumps called planetesimals (small planets): the planetesimals that condensed first nearest to the sun were made of materials that had high melting points like iron. Mercury is mostly iron and is the densest of the planets: as the distance from the sun increased in the accretionary disk the temperature dropped allowing those materials with slightly lower melting points to begin to condense. Earth, being the third planet from the sun, is less dense than mercury and is a mixture of iron, nickel, silica, and oxygen. Further out from the sun the lightest elements were able to condense but only as gases. Jupiter may be the largest planet but it is also the least dense planet made mostly of hydrogen and helium. The early earth: many planetesimals formed along rings at specific distances from the sun. As they cooled and condensed they were still very hot.
