Astronomy 2021A/B Chapter Notes - Chapter 2-3: Cosmic Microwave Background, Virgo Supercluster, Cosmic Calendar
19 Apr 2017
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Document Summary
Earth lost its place as the centre of the universe during the copernican revolution, imagined planets around other stars. Old astronomy focused on the movements of light in the sky to tell time, seasons, tides. 2000 years later kepler described the laws by which planets orbit the sun, knew how planets orbited the sun but now why. Newton discovered the why, sun has gravity just like earth, he ended the ancient distinction between earth and the heavens merging them into one universe. Universe is vast and old, endless possibilities for life to have arisen and plenty of time for it to evolve. Elements that make up earth are present elsewhere, laws of nature are the same everywhere. Cosmic address: universe -> local supercluster -> local group -> milky way galaxy -> solar system -> earth. Galaxies contain a few hundred million to a trillion or more stars, milky way is relatively large, 100 billion stars.
