Used with
permission of Maiken Naylor, University at Buffalo, Buffalo, NY, USA,
http://ublib.buffalo.edu/libraries/units/sel/exhibits/stamps
Aristarchus of Samos (3rd century BC) considered the sizes and distances of the sun and the moon, and was the first to try to calculate the distances of these bodies geometrically . Furthermore, he advanced the theory that the sun was at rest at the center of the sphere of fixed stars, and that the earth and planets revolved around the sun. The apparent motion of the stars was due to the daily rotation of the earth. Copernicus was familiar with Aristarchus' theory of the universe, which at the time, however, did not find favor with the ancient philosophers.