EPSC 201 Lecture Notes - Lecture 2: Heliocentrism, Dark Matter, Asteroid Belt
29 Nov 2017
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Document Summary
Complex, conscious thought distinguishes humans from all other species. Ancients knew that stars moved around a set point. Earth sat at the center of theh universe. The moon, planets and stars circled a motionless earth. Ptolemy proposed equations to predict movements of the planets. Pythagoras discovered earth was sphere and that planets moved in circular path through following plato. Aristarchus was first to adopt sun at centre o funiverse and solar system. Measured relative size of earth whose actual size was later measured by eratosthenes. Aristotilean/ptolomeic view that the earth centered everything hold until renaissance in europe in 1500. Copernicus and galileo sutdies led to acceptance of earth and planets orbiting the sun. Newton - planet motion explained by theory of gravity. Cereated very simple law about what force is. Unseeable matter that gives mass to the galaxy. Stars are immense balls of incandescent ionized gas. Over 100 billion galaxies exist in the visible universe.
