ASTRO-110 Lecture Notes - Lecture 16: Weakly Interacting Massive Particles, Gravitational Lens, Solar Mass
18 Sep 2020
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Document Summary
Our best models for galaxy formation assume. Matter originally filled all of space almost uniformly. Gravity of denser regions pulled in surrounding matter. H and he gases in these clouds formed the first stars. Supernova explosions from first stars kept much of the gas from forming stars. Leftover gas settles into spinning disk (conservation of angular. Spin: initial angular momentum of protogalactic cloud could determine size of. Density: elliptical galaxies could come form dense protogalactic clouds that were resulting disk able to cool and form stars before gas settled into a disk disturbed. Collisions were much more likely early in time because galaxies were close together. Many of the galaxies we see at a great distance (early times) ineed look violently. The collisions triggered bursts of star formation. Modeling such collisions on a computer shows that two spiral galaxies can merge. Collisions may explain why elliptical galaxies tend to be found where galaxies are to make an elliptical closest together.
