... 9a. Earth orbits Sun? . ... As noted earlier , Aristarchus of Samos proposed that the Earth revolved around the Sun, but the idea was rejected by later Greek astronomers, in particular by Hipparchus. ... For a discussion of the discovery of the solar system which includes a "moving picture" illustrating retrograde motion, click here . ... The full story of the discovery of the solar system--of Copernicus, Galileo, Tycho and Kepler--is long and would take this discussion too far afield. ...