AST 2002 Lecture Notes - Lecture 17: Big Bang, Antiparticle, Weak Interaction
Document Summary
The universe must have been much hotter and denser early in time. Photons converted into particle- antiparticle pairs and vice versa: e=mc^2. The early universe was full of particles and radiation because of its high temperature. In the beginning, mater created and annihilated constantly. Amounts of matter and antimatter were nearly equal. (rough one extra proton for every 10^9 proton-antiproton pairs!) At ~0. 001 s, matter annihilates remaining antimatter and atomic nuclei start forming (h) At ~380,00 years, atoms formed and background radiation was released. We have detected the leftover radiation from the big bang. The in bang theory correctly predicts the abundance of helium and other light elements in the universe. The microwave background wave radiation: the cosmic microwave background is the radiation left over from the big bang. The planck satellite gives us detailed baby pictures of structure. Big bang theory prediction: 75% h, 25% he (by mass) matches observations of nearly.
