Eudoxus (of Cnidus)

Eudoxus (of Cnidus) (408-355 bc), Greek astronomer and mathematician, who made important contributions to the field of geometry and who proposed the first systematic explanation for the motions of the sun, moon, and planets. Eudoxus was born in Cnidus (in what is now Turkey). He became a pupil of the Greek philosopher Archytas and studied for a short time under the Greek philosopher Plato. Later Eudoxus founded a school at Cyzicus.

Eudoxus is often credited with the discovery that the solar year is about 6 hours longer than 365 days. Eudoxus also attempted to explain the motions of the sun, moon, and planets through a model of the solar system based on a complicated arrangement of rotating spheres. His model was moderately successful in predicting these motions. Eudoxus also made important discoveries in mathematics. It is believed that he discovered much of the geometry later included in Elements, the comprehensive treatise on mathematics written by the Greek mathematician Euclid.