fl. fifth century B.C.

Pythagorean philosopher whose idea of a spherical universe exerted considerable influence on later Greek astronomy. According to Philolaus, the universe consisted of concentric, or nested, spheres at the center of which was a central fire that was never visible to man because Earth is always turned away from it. Earth, an anti-Earth, and the other heavenly bodies, including the Sun, all moved in circular orbits about this central fire.