d. c. 150 B.C.

Chaldean astronomer who speculated that the tides were caused by the motions of the Moon. Born in the Babylonian town of Seleucia, he is today primarily remembered as the only known supporter of Aristarchus's heliocentric theory, maintaining that it accurately described the physical structure of the universe. In particular, he accepted Aristarchus's conjectures concurring the centrality of the Sun, Earth's diurnal rotation, and the infinity of the universe.