ASTR 340 Lecture Notes - Lecture 17: 2Degrees, Particle Horizon, Alan Guth
Document Summary
Universe grew by a factor of 10^30 in a very short time. Exponential growth: usually the universe"s size grows much more slowly, even when it was matter/radiation dominated. Gravitational waves that imprint weak features in cmb detected. Density waves due to gravity are the result of everything around us. Swirly-ness in cmb = evidence of light polarization/density. Experiment results rejected but future exp may be able to see through milky way dust. If the universe is flat now, then it was very very flat at earlier times but math says this is unstable. Any small fluctuation would be greatly amplified with time. This is reversed with inflation, drives universe towards omega=1. Consider epoch of recombination: particle horizon means things separated by more than 2 degrees. Should not have had contact: but somehow still homogeneous/isotropic and at same cmb temp, with inflation, these particles did have contact, universe just expanded more.
