GE CLST 70A Lecture Notes - Lecture 13: Seismology, Radioactive Decay, Kuiper Belt
23 Jan 2017
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87% of meteorites that fall to earth. Contain chondrules, pre-solar grains, organic matter, and water. Composition is solar, except for h and he. Not formed from a single exploded planet, but are planetesimals that have always been small. This indicates that no planet ever formed in the region between mars and jupiter. Total mass of the asteroid belt: 1/2000 earth masses. Jupiter"s enormous gravity prevented the accretion of a planet where the asteroid belt currently is. Main parts: nucleus, coma, dust tail. The ion tail is always pointed away from the sun, regardless of the comet"s direction. The dust tail follows right behind the comet. Nucleus cannot actually be seen because of its atmosphere. Comets are usually on highly elliptical orbits, coming from the outer solar system and sling- shotting around the sun. They become visible once they get close enough to the sun for the gases in their nucleus to heat up and be released (around mars/jupiter)
