In 499 CE — when he was just 23 years old — Aryabhata wrote the Aryabhatiya, a 118-verse mathematical and astronomical treatise over a millennium ahead of its time. Working entirely from observation and pure mathematical reasoning in Kusumapura (modern Patna), he calculated π as 3.1416 — within 0.01% of the modern value. He computed the length of Earth's sidereal day as 23 hours, 56 minutes, 4.1 seconds — within 0.01 seconds of the modern value — and measured Earth's circumference to within 0.2% accuracy. He correctly explained that solar and lunar eclipses are caused by the Earth's shadow and the Moon's shadow, not by a mythical demon swallowing the Sun — a revolutionary claim in 499 CE. He stated that the Moon and planets shine by reflected sunlight. He proposed that the Earth rotates on its own axis — 1,000 years before Copernicus. His work was adopted by Islamic astronomers in Baghdad in the 8th century and transmitted to Renaissance Europe, where it formed part of the intellectual bedrock of modern astronomy.
Key Contribution
Calculated π to 0.01% accuracy (499 CE). Computed Earth's sidereal day to within 0.01 seconds of the modern value. Correctly explained eclipses as shadows, not mythology. Proposed Earth's rotation on its axis — 1,000 years before Copernicus. India's first satellite (1975) was named "Aryabhata" in his honor.
“Just as a person in a moving boat sees stationary objects moving in the opposite direction, so the stars appear to move westward for a person on Earth — it is the Earth that rotates.”
— Aryabhata
Works & Achievements
- ✦Aryabhatiya (499 CE) — written at age 23
- ✦π = 3.1416 — within 0.01% of modern value
- ✦Sidereal day: 23h 56m 4.1s — within 0.01 seconds of modern value
- ✦Correct explanation of solar and lunar eclipses
- ✦Earth rotates on its axis — proposed 1,000 years before Copernicus
- ✦India's first satellite named "Aryabhata" in his honor (1975)