AST2002 Lecture Notes - Lecture 23: Elliptical Galaxy, Spiral Galaxy, Active Galactic Nucleus
Document Summary
Takes about 1 billion years for a galaxy to form. The extremely distant galaxies that we see can be seen from old light from young galaxies. Elliptical galaxies result from pressure pushing the gas within it in all directions. Spiral galaxies result from pressure pushing one way and another. The forces pushing the gases is what determines if the galaxy will become an elliptical or spiral one. The extending arm made from the first-generation stars helps slow down the spinning. The bigger the redshift, the faster away it is moving away from the relative point and the older it is. According to modern computer simulations, at the beginning of the universe, many collisions took place. Two galaxies colliding together can either trigger or accelerate star formation. Giant elliptical galaxies located at the center of clusters can begin to consume other smaller galaxies.
