Photo: Krishnachandranvn · CC BY-SA 4.0Aryabhata’s book of 121 verses in four parts, on mathematics, time-reckoning and the sphere, written when he was 23.
Aryabhata states that he was 23 when 3,600 years of the Kali Yuga had passed. The Ganitapada gives the circumference of a circle of diameter 20,000 as 62,832, which is pi to four places, and a table of sines. The Golapada says the stars seem to move west just as the bank seems to move backwards to a man in a moving boat, for it is the earth that turns.
It dates itself by the Kali Yuga reckoning, and set the course of Indian astronomy for a thousand years.
ScienceHigh-carbon steel made in sealed clay crucibles in South India, the metal behind the famous watered “Damascus” blades.
ScienceThe “rules of the cord”: exact instructions for laying out the altars of the Vedic yajna, and with them the oldest geometry of Bharat.
ScienceA 7.2-metre wrought-iron column of about six tonnes, forged as a dhvaja of Vishnu and still almost free of rust after sixteen centuries.
ScienceThe astronomical work in which Brahmagupta, aged thirty, first set down rules for calculating with zero and negative numbers.
ScienceA line of teachers and pupils, begun by Madhava of Sangamagrama, who found infinite series for pi and for the sine and cosine some three centuries before Europe.
ScienceGiant instruments of masonry, built to measure time and the positions of the sun, moon and stars with the naked eye.
