Aryabhata Born
Aryabhata, born in 476 AD, became one of the most influential mathematicians and astronomers of the ancient world. His compact Sanskrit treatise, the Aryabhatiya, shaped Indian astronomy for centuries and carried ideas about number, planetary motion, and eclipses that later spread to the Islamic world and beyond.
Aryabhata was born in 476 AD, a date that comes from his own work, in which he states that he was 23 years old when 3,600 years of the Kali Yuga had passed. His birthplace is less certain. He tells us he wrote at Kusumapura, usually identified with the area of Pataliputra, modern Patna, which was a major center of learning in the late Gupta period. Some later traditions link him to Kerala, but historians remain divided on this. The Gupta era was a time of notable activity in Indian mathematics and astronomy, and Aryabhata worked within a tradition that had already absorbed influences from earlier Indian schools and, probably, from Greek astronomy.
The Aryabhatiya, composed around 499 AD, is a short work of about 120 verses divided into four sections. It covers a system of numerical notation, mathematical rules, time reckoning, and the geometry of the heavens. Among its mathematical contributions is an approximation of pi as 62,832 divided by 20,000, which is about 3.1416. He described it as approximate, and some later commentators read this as a sign that he understood the number to be irrational, though this interpretation is debated. He also gave methods for square and cube roots, the area of triangles, sums of series, and a technique for solving certain linear equations with whole-number solutions, often called the kuttaka method.
In astronomy, Aryabhata stated that the Earth rotates on its axis, which explains the apparent daily motion of the stars. This was a bold claim in his time. Whether he also proposed that the planets orbit the Sun is a matter of scholarly argument. His planetary models used a complex system of epicycles, and the description of him as a true heliocentrist is generally considered an overstatement. He did, however, explain lunar and solar eclipses as the result of shadows cast by the Earth and Moon, rejecting the mythological explanation involving a demon swallowing the Sun or Moon.
His legacy was considerable. Later Indian astronomers such as Bhaskara I wrote commentaries on his work, and some critics, including Brahmagupta, argued with parts of it. Arabic translations of Indian astronomical texts carried his ideas to scholars in the Islamic world, where he was known as Arjabhar. India honored him in 1975 by naming its first satellite Aryabhata, a fitting tribute to a thinker whose work helped shape the study of the sky.