ASTR-1010 Lecture Notes - Lecture 10: Electroweak Interaction, Planck Time, Planck Units
6 Oct 2016
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Document Summary
The early universe must have been extremely hot and dense. Four known forces in universe: strong force, electromagnetism, weak force, gravity. Planck era: before planck time (~10-43 sec, no theory of quantum gravity. Gut era: lasts from planck time (~10-43 sec) to end of gut force time (~10-38 sec) Electroweak era: lasts from end of gut force (~10-38 sec) to end of electroweak force (~10-10 sec, physical conditions now become similar to conditions we can recreate in labs. Particle era: amounts of matter and antimatter nearly equal. Roughly 1 extra proton for every 109 proton-antiproton pairs. Era of nucleosynthesis: begins when matter annihilates remaining antimatter at ~0. 001 sec, nuclei begin to fuse. Era of nuclei: helium nuclei form at age ~3 minutes, universe has become too cool to blast helium apart. Era of atoms: atoms form at age ~380,000 years, background radiation released. Era of galaxies (present era: galaxies form at age ~1 billion years.
