PCS 181 Chapter 3: Unit 3
28 Feb 2017
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Recall the cobe satellite which confirmed the cmb ~ 3k (2. 728k) (remember this) Another recall is that the kalvin scale has no negatives number. Cobe was later asked to seek very small temperature variations in the cmb. Gala(cid:454)(cid:455) theo(cid:396)ists h(cid:455)pothesize that gala(cid:454)ies (cid:862)(cid:272)o(cid:374)de(cid:374)sed(cid:863) at the i(cid:374)te(cid:396)fa(cid:272)e (cid:271)etwee(cid:374) warmer and cooler volumes of space. The first stars formed after the big bang were extremely massive: 100x more mass than our sun. These stars only lived a few million years an exploded as supernovae: leaving black holes as remnants, these massive black holes attracted gas/dust into orbit. Over time, more matter was attracted until a galactic mass was present. Massive black holes are found at the centers of most galaxies. Sgr a* is 4 millions more than a mass of a star 4 x 106 mo. A galaxy is a gravitationally-bound collection of stars, gas, dust, radiation. Galaxies range from thousands to hundreds of thousands of light years across.
