AY 101 Lecture Notes - Lecture 33: Cosmic Microwave Background, Einstein Ring, Quasar
Document Summary
Intro to dark matter, gravitational lensing, galaxy formation. Ordinary (baryonic matter: matter made of protons, electrons, and neutrons, neutral atomic and molecular, plasma. Degenerate matter: baryonic matter compressed to extremely high density, white dwarfs, neutron stars. Dark matter is a form of matter that is detectable only through its gravitational influence. It does not emit light like conventional matter does, he(cid:374)(cid:272)e it is (cid:862)dark(cid:863) Why is dark matter important: most of the matter in the universe is believed to be dark. Do we know what the dark matter actually is: no. Principal evidence: detection of higher than expected speeds of stars and gas clouds orbiting in galaxies, or of individual galaxies orbiting in galaxy clusters. Existence implied when speeds do not match to the mass we can actually see. Dark matter in spiral galaxies is detected from higher than expected rotation speeds at large distances from the center.
