The Greek astronomer Aristarchus of Samos (ca. 310-230 BC) hypothesized that the earth revolves yearly about the sun and daily rotates about its own axis. He attempted to determine the relative sizes and distances of the sun, moon, and earth.

Born on the island of Samos, Aristarchus studied at Athens in the Lyceum under Straton of Lampsacus, who was the head of the Peripatetic school from 288/287 to 270/269 B.C.

Heliocentric System

Though Aristarchus is known to have written on problems of vision, light, and color, his primary work was in astronomy, specifically on the interrelations of the sun, moon, and earth. With respect to their relative positions he pointed out that, mathematically, one can imagine the earth rotating about the sun as easily as the sun about the earth; all that is required is a vastly increased radius of the sphere of the fixed stars and the daily...