ASTRO 142 Chapter Notes - Chapter 14: Galaxy Formation And Evolution, Sound Horizon, Great Attractor
Document Summary
Newtonian model: assumed the existence of an infinite space, filled uniformly with an infinite number of stars. Hoped that this would solve the problem of gravitational collapse. Did not, as it was gravitationally unstable. Edmund halley: stars are too far away. If there is an infinite number of stars, it should explain how far away they are. Olbers" paradox: light goes through a gel that permeates the universe and absorbs light. Due to the 2nd law of thermodynamics, the gel should heat up and emit as much light as what was lost. Thought it may be due to the expansion of the universe. Is actually due to the fact that stars have a finite lifespan. Two greatest cosmological observations of the 20th century: discovery of the expansion of space and cosmic background radiation. Big bang proposes that the matter density and temperature were very high and the universe was opaque; matter and radiation constantly exchanged energy.
