AST-1A Lecture 29: Ast-1A - Day 29
Document Summary
Scientific model- a theory that accounts for a set of observations in nature. The notion that the stars reside on a giant celestial sphere is one such model. Scientific model is not truly physical model. Pythagoras- in 500 b. c. he saw universe as a set of 8 concentric spheres with earth at the center. (moon, planets, sun, and stars at the time) Anaxagoras- between 500 and 428 b. c. he said that the sun must be a large body located far from earth. Plato- around 400 b. c. he argued for uniform circular motion only in circles at constant speed. Aristotle- by 322 b. c. he had increased the number of spheres in the geocentric model to 55. He said that nothing could rotate, or else people would be thrown off. He thought earth was the center of the universe. He said that earthly objects would fall down and stop. Heavenly objects keep moving in circles (bought into plato"s idea)
