AST 111 Lecture Notes - Lecture 23: Weak Interaction, Weakly Interacting Massive Particles, Strong Gravity

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

Document Summary

Does dark matter really exist? gravity to observations of the orbital speeds. Case for dark matter rests primarily on applying newtons laws of motion and. Either dark matter exists or our current understanding of gravity is incorrect. Most of the mass detected by gravitational lensing is not in the same place as the hot gas. 1) ordinary matter: protons, neutrons, and electrons. 2) exotic matter: different from those in ordinary atoms account for most of the dark matter. States as percentages of the critical density. Must focus on density and not mass. Clearly there"s not a lot of dark matter that needs to be accounted for. Calculations based on the big bang model indicate that ordinary matter cannot. Higher the density the more efficiently fusion would have proceeded. Ordinary matter in the universe is around 5% of the critical density. Dark matter is made up of exotic particles. Neutrinos are dark by nature with no electrical charge and cannot emit.