AST201H1 Chapter Notes - Chapter 23: Cosmic Microwave Background, Planck Units, Universe Today

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST201H1
• Professor: Michael Reid

Document Summary

The universe has progressed through a series of eras, each market by unique physical conditions. We know little about the planck era, when the four forces may have all behaved as one. Gravity became distinct at the start of the gut ear, which may have ended with the rapid expansion called inflation. Electromagnetism and the weak force became distinct at the end of the electroweak era. Matter particles annihilated all the antimatter particles at the end of the particle era. Fusion of protons and neutrons into helium ceased at the end of the era of nucleosynthesis. Hydrogen nuclei captured all the free electrons, forming hydrogen atoms at the end of the era of nuclei. Galaxies began to form at the end of the era of atoms. The era of galaxies continues to this day. The density of the early universe really did differ slightly from place to place.