PCS 181 Lecture Notes - Lecture 2: Galaxy Zoo, Globular Cluster, Big Bang
24 Nov 2016
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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 asked to seek very small temperature variations in the cmb. Gala(cid:454)(cid:455) theorists 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)terfa(cid:272)e (cid:271)et(cid:449)ee(cid:374) warmer and cooler volumes of space. Black hole in the center of galaxies which has a greater mass then the sun itself. A galaxy is a gravitationally- bound collection of stars, gas, dust and radiation. Galaxies range from thousands to hundreds-of thousands of light years across. Galaxies contain from thousands to trillions of stars. The milky-way our own galaxy, is about 100,000 to 120,000 light years across. Our milky-way is in the local group which consists of about 40 member galaxies. Our sun lies about 8kpc ~ 26,000 light years (ly) from the center of the milky-way. Our sun travels around the milky-way galaxy at ~ 220km/s.
