ASTRON 100 Lecture Notes - Wilkinson Microwave Anisotropy Probe, Cosmic Microwave Background, Grand Unified Theory
21 Jan 2014
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Document Summary
The early universe must have been extremely hot and dense. Photons converted into particle-antiparticle pairs and vice versa. The early universe was full of particles and radiation because of its high temperature. Electromagnetism - holds atoms and molecules together. Weak force - important for fusion/fission, affects neutrinos. * forces begin to unify at high temperatures. No theory to explain the universe during this time. Strong, weak, and em operated as a single force. Lasts from planck time (~10^-43 sec) to end of gut force (~10^-38 sec). Lasts from end of gut force (~10^-38) to end of electroweak force () Number of particles ~ number of photons. Amounts of matter and antimatter nearly equal (roughly 1 extra proton for every 10^9 proton - antiproton pairs) Begins when matter annihilates remaining antimatter at ~0. 001 second. Helium nuclei form at age ~ 5 minutes. Universe became too cool to blast helium apart. Sets the amount of helium we see today - 25% helium.
