AST 111 Lecture 24: Ast 111 - Lecture 24

• School: Tunxis Community College
• Department: Astronomy
• Course: AST 111
• Professor: Reynolds

Document Summary

Dark energy and the fate of the universe. 1) ongoing expansion driving galaxies apart form one another. 2) gravitational attraction assembling galaxies and larger scale structures. Four expansion models therefore expansion would slow down, stop entirely and then reverse. Recollapsing universe: strong gravitational expression and no repulsive force. Critical universe: gravitational attraction is not quite strong, expansion would. Coasting universe: weak gravitational attraction and no repulsive force. Accelerating universe: repulsive force strong enough to overpower gravity, decelerate forever expansion would accelerate. Existence of some force that acts to push galaxies apart. We still don"t know what dark energy is, but observations of how it changes with. Dubbed dark energy time might provide clues. Fate exactly equal to the critical density. Flat geometry implies that the total density of matter plus energy in the universe is. Dark matter is accounts to about 70% of the total mass-energy of the universe.