ISP 205 Lecture Notes - Lecture 14: Cosmic Microwave Background, Triple-Alpha Process, Planck Units
3 Sep 2018
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Document Summary
Each step leaves behind evidence, less certain about earlier moments than later ones, go backward in time and look: detected leftover radiation from big bang, big bang theory correctly predicts the abundance of helium and other light elements. Matter is packed closely together, go back see temp 1 sec after big bang, before big bang, and now temp hotter farther back, can conclude much hotter and denser, full of radiation and particles because high temps. Background radiation freely streaming across universe since atoms formed, expansion redshifted thermal radiation from atoms era to ~1000 times longer wavelength, microwave observations give detailed pics from baby ages of structure in universe. Protons and neutrons make helium ~5 minutes old. Separation of gut force may have triggered inflation; uniformity, flatness, and structure features not explained by original big bang theory; patterns in microwave maps temp/density differences seeds structure formation, inflation models make specific predictions about these patterns.
