CAS AS 100 Chapter Notes - Chapter 20, 22: Nucleosynthesis, Cosmic Microwave Background, Galaxy Formation And Evolution

• School: Boston University
• Department: Astronomy
• Course: CAS AS 100
• Professor: Michael Mendillo

Document Summary

~after hubble discovered the expansion of the universe, it became clear that the universe must have had a beginning and that the portion of the universe that is observable to us must be finite in size. The expansion tells us that in the past the galaxies must have been closer together. Entire universe came into being at one single moment. Cosmological principle- the idea that matter in the universe is evenly distributed, without a center or an edge. The balloon analogy can better explain this concept than the raisin cake. ~the hubble constant tells us how long our universe has been expanding. Changes with time but stays constant at 1 over the age of the universe. Its constant because it is the same at all locations in the universe. A more precise value will be given if we know whether the expansion has been speeding up or slowing down over time.