AST 1001 Study Guide - Midterm Guide: Barred Spiral Galaxy, Active Galactic Nucleus, Spiral Galaxy
Document Summary
Interstellar medium: makes new star systems, dusty gas clouds obscure view b/c they absorb visible light, dynamic; primary features: disk, bulge, halo. A in direction of galactic center; globular clusters found in halo&disk; blue stars near/in star-forming clouds. <10 -43 sec, temp: >10 32 k, all forces may be unified; gut era : time: 10 -43 -10 -38 sec, temp: 10 32 -10 29 k, began when gravity became distinct; electroweak era : time: 10 -38 -10 -10 sec, temp: 10 29 -10 15 k, all electromagnetic forces unified into gut forces; Nucleosynthesis era : time: . 001sec-5min, temp: 10 12 -10 9 k, begins when matter wrecks nuclei antimatter at ~0. 001 sec (nuclei fuses); nuclei era : time: 5min-380,000yrs, temp: 10 9 -3000k, universe becomes too cool to blast helium apart; Atoms era : time: 380,000-1bil yrs, temp: 3000-20k, background radiation is released; galaxies era: time: 1 bil-present, temp: 20-3k, first stars/galaxies formed.
