AST201H1 Lecture Notes - Lecture 22: Cosmic Microwave Background

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST201H1
• Professor: Bryan Gaensler

Document Summary

If it"s the case that the universe begin in a hot, dense state as hubble"s law claims, we have to think about what else happens. Should the enire universe once have been that intensely hot, then (the hypothesis is), there should be radiaion produced by this hot, dense state. And so the observaion we search for is this light. Being the case that universe began dense and hot, it must have produced a blackbody spectrum as it was dense (and all dense objects have blackbody spectrums: the colour does not mater, we look for the light irst. Instantly, the universe goes from completely opaque to completely transparent. And this is the moment when the light from the big bang actually did anything. Eventually one day it"ll reach one day where it cannot be detected at all. And as predicted, the cmb has a nearly perfect blackbody spectrum.