Astronomy AST-A 100 Lecture Notes - Lecture 6: Flattening, Orion Nebula, Interstellar Cloud
20 Oct 2016
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I(cid:373)(cid:373)a(cid:374)uel ka(cid:374)t put forth his (cid:862)ne(cid:271)ular hypothesis(cid:863: solar system was formed from gradational collapse of interstellar cloud, mu(cid:272)h evide(cid:374)(cid:272)e has (cid:271)ee(cid:374) a(cid:272)(cid:272)u(cid:373)ulated so that today it s a theory: You are made of star dust: solar nebula: 98% hydrogen & helium 2% heavier elements. Three mechanisms occur as solar nebula-solar system: heating: consists of energy: gravitational-radiative heat, spinning: consists of angular momentum, spin rate increases as coupes occurs, flattening: collisions cause elliptical orbits to become circular. Plant formation: as the solar nebula collapses, gravity brings together enough material to form the sun in the center. In the surrounding disk, matter is spread too thinly for gravity to alone clump it together. What we need ae seeds: seeds are small solid bit of matter from which gravity can ultimately build planets, any gas or liquid can become a solid seed if the temp is low enough. Look at the composition of the solar nebula and their corresponding condensation temps:
