ASTR 1103 Lecture Notes - Lecture 17: Virgo Cluster, Redshift, Observable Universe
9 Feb 2020
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Document Summary
Cosmology: the study of the nature, origin, and evolution of the universe. The hubble law: the recessional speed of galaxies is proportional to their distances from us. Is the age of the universe, determined from the hubble constant (13. 8 billion years) Imagining the big bang: galaxies evolved from a state of extreme density and temperature, there was no center. Particles and nucleosynthesis: particles and antiparticles have opposite properties (charge, rotation, etc, examples include, proton antiproton, neutron antineutron, electron positron. Ages of the universe: radiation dominated era (0-50 thousand years, matter dominated era (50 thousand to 9 billion years, dark energy dominated era. (9 billion years to present) Pair production: photons with enough energy they can cause change to particles and antiparticles. Annihilation: when particles and antiparticles meet, they produce gamma-ray photons. Age: less than . 0001 seconds: temperature: more than 1 trillion k, photons and heavy particles change into each other.
