EPSC 201 Lecture Notes - Lecture 3: Sug, White Dwarf, Crab Nebula
11 Mar 2013
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Document Summary
Universe ex- panded, and temperature decreased further: 2 up quarks + 1 down quark = proton, 2 down quark + 1 up quark = neutron, proton + neutron = hydrogen nucleus. Energy throughout the early universe was being bounced around, and made it impossible to discern any- thing. From this point on, we can observe the universe. At 6000 degrees, it was cold enough to start observing. At about 379 years after the big bang, the background scattering effectively stopped. Atoms have formed and matter has spread out. Cannot observe before 379 years due to energy scattering. This all occurred when the uni- verse was about 6000 degrees kelvin. Bell lab scientists observed this radiation in the sixties. Scientists calculated that there would be a specif- ic background radiation at 2. 75 de- grees, and if the background radiation is measured from space, it is found to be the same wavelength.
