Statue at IUCAA, Pune, India
Aryabhata
476 – 550
Indian
Ancient World
Calculated Earth's rotation, eclipses, and the value of pi
Biography
India's first satellite Aryabhata (1975), named in his honor
ISRO, Government of India
Aryabhata was one of the greatest mathematicians and astronomers of the ancient world. Born in Kusumapura (modern Patna, India), he composed his masterwork, the Aryabhatiya, at the age of just 23. This concise treatise in verse covered arithmetic, algebra, plane and spherical trigonometry, and astronomy.
Remarkably, Aryabhata proposed that the Earth rotates on its own axis — a concept that would not gain acceptance in Europe for another thousand years. He correctly explained eclipses as shadows cast by and on the Earth, rejecting the mythological explanation involving the demon Rahu.
His astronomical calculations were astonishingly accurate. He computed the length of the sidereal year as 365 days, 6 hours, 12 minutes, and 30 seconds — just 3 minutes and 20 seconds longer than the modern value. His work deeply influenced Islamic and European astronomy through Arabic translations.
Key Discoveries
• Proposed that Earth rotates daily on its axis
• Correctly explained solar and lunar eclipses as shadow phenomena
• Calculated the sidereal year to within 3 minutes of the modern value
• Approximated pi as 3.1416 — accurate to four decimal places
• Developed trigonometric tables (sine) used for centuries