EAR 105 Lecture Notes - Lecture 1: Big Bang, Cosmic Microwave Background, Solar System
18 Sep 2018
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Document Summary
Early astronomers looked and guessed , some measurements. The stars are fixed relative to each other. All the stars rotate about a fixed point. The planets move against the background of stars. Not obvious that the earth is one of many planets. Not obvious that the sun is a star. Renaissance: a new age of discovery in 1400s europe. It spawned a new age of scientific exploration. The planets follow a different pattern asteres planetai which means wandering star . Early ideas were guided by belief that we were the center of the universe. It was the birth of the empirical study where the theorist honored the data rather than espousing a specific theory. Tested rather working to prove an idea. Telescope allow astronomers to better see the universe. 100 billion galaxies constitute the visible universe. Milky way galaxy: the galaxy that contains in the milk way. 300 billions stars in the milky way.
