AST 2002 Chapter Notes - Chapter 17: Photon, Planck Units, Grand Unified Theory
Document Summary
If they run into each other, their mass- energy becomes photon energy again: there are four forces responsible for everything in the universe, gravity. Holds planets, stars, and galaxies together: electromagnetism. Much stronger than gravity, not on large scale though: strong force. This ended when the temperature dropped below 1032 k: the gut era began next. The energy released near the end could have caused inflation of the universe, dramatic expansion: the electroweak era had three forces happening: gravity, strong force, and electroweak force. Cooling and expanding occurred continually through this era: the particle era is between the end of the electroweak era and he moment spontaneous particle production ended. Antiprotons were slightly outnumbered by protons during this time. Quarks are the building blocks of protons and neutrons, no longer found freely in the universe: the era of nucleosynthesis. Most of the universe"s helium was made during this time, in the first five minutes.
