Aryabhata the Elder (AD 476–c. 550)
Aryabhata the Elder was a Hindu astronomer and mathematician whose surviving masterpiece, Aryabhatiya, written in verse, contains one of the earliest treatments of algebra and some remarkably advanced astronomical knowledge. It argues that the planets move in elliptical paths, the apparent rotation of the heavens is due to Earth's axial rotation, and the Moon and planets shine by reflected sunlight. Aryabhata also correctly explained the causes of solar and lunar eclipses – improving upon the then-popular Indian belief that eclipses were the work of a demon called Rahu – and gave a value for the length of the year that is just a few hours longer than the one accepted today.