PHIL 160D3 Lecture Notes - Lecture 19: Falsifiability, Galilean Moons, Tychonic System
5 May 2017
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Document Summary
Copernican model strengths: accurate predictions, no equant points for perfect circle fact, simple explanation for retrograde motion. Copernican model weakness: available evidence supports geocentrism, not heliocentrism. Modern geocentrism: tychonic system is best available geocentric model. Tychonic model: sun and moon orbit the earth, all other planets orbit the sun. Tychonic model is mathematically equivalent to copernican model. Kepler"s first law law of ellipses. The path of planets around the sun is elliptical. The center of the sun is located at one focus. Kepler"s second law law of equal areas. Line drawn from center of sun to center of planet will sweep out equal areas in equal intervals of time. Planets do not orbit at a constant speed. Speed is faster when close to the sun. Kepler"s third law law of harmonies. The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.
