ASTR 1200 Chapter Notes - Chapter 1: Local Group, Observable Universe, Ecliptic
9 Sep 2015
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1. 1 our modern view of the universe: like everything else, we have our own place in the universe. This is our cosmic address. : earth is part of the solar system, which also includes the planets and their moons, comets, asteroids, and other smaller objects. Our solar system is part of the milky way galaxy, a disk-shape swirl of stars, and we are a little over halfway out from the center. Superclusters usually have tightly packed galaxies right next to each other, but they are usually spread out in a chain or large sheet with large voids between each. All of these combined are our universe: about 14 billion years ago, the big bang happened, which was the beginning of the expansion of the universe and spreading of the galaxies. The distances are slowly increasing over time: even thought the universe is ever expanding, the galaxies and galaxy clusters are not. This fuses lightweight atomic nuclei to form heavier nuclei.
