ASTR 20 Lecture Notes - Lecture 10: Protostar, H Ii Region, Star Formation
Document Summary
The light from galaxies is centrally concentrated. Flat rotation curves show that the universe is dominated by the presence of dark matter but dark matter has never been detected. There has to be a force binding the clusters together. Leading the to indication of dark matter. Dark matter is material that emits low light per unit mass. Cannot be anything that is made from stars. Ex: hard metals, rocks, planets, black holes, dwarf stars. Ex: massive neutrino, weakly interacting massive particles, cosmic strings, modified gravity. Clearly ruled out by space telescope observations. Observations strongly fail to confirm their existence at the required number density. Not detected despite 40 years of experiments and expectation that detection is just around the corner. Until dark matter is actually detected it remains just like an epicycle. Standard idea much greater than any single star. Star formation has to form inn clusters because the mass of the self gravity is.
