Jonathan Dickinson Astronomy Laboratory Sept. 9, 2002 Geocentric versus Heliocentric Or why the average 13 year-old is not really the center of the universe, I am. You are here Jonathan Dickinson Astronomy Laboratory Sept. 9, 2002 http://www.courses.vcu.edu/PHYS-aab/PHYZ103/

The Theories: Geocentric Ptolemaic Universe Universe consists of concentric spheres with earth at the center. Moon, Sun, Mercury, Venus, Mars, Jupiter, and Saturn each have their own sphere. The stars are all one sphere. All heavenly motion (read astronomical) is consists of perfect uniform circular motion. The acceptance of this theory was influenced by Aristotle’s acceptance of it. Later this theory was given the support of the Roman Catholic Church. http://csep10.phys.utk.edu/astr161/lect/retrograde/aristotle.html

The Theories: Heliocentric Copernican Universe Planets orbit around the Sun, which is the center of the universe. The earth rotates. The moon orbits around the earth. The stars have a fixed location. Galileo’s legendary comment, “But it does move.”