Ancient Sciences

Āryabhaṭa was born in 476 CE and completed his great mathematical and astronomical treatise, the Āryabhaṭīya, in 499 CE — at age 23. The text, comprising 118 verses in four chapters (Gītikapāda, Gaṇitapāda, Kālakriyāpāda, and Golapāda), is one of the most consequential scientific texts ever written. In it, Āryabhaṭa articulated the complete decimal place-value system — the numerical framework in which the value of a digit is determined by its position — with explicit definition and named places up to 10⁹ (one billion). This is the arithmetic system used by every person on earth today. The decimal place-value system required the concept of zero — not just as a placeholder in writing but as a mathematical entity with defined properties. While zero as a written placeholder is attested in Indian inscriptions from the 3rd–4th century CE (the Bakshali manuscript, dated variously between 224–383 CE), Āryabhaṭa's system operationalizes it fully: the "empty place" (śūnya) enables positional notation that makes arithmetic of large numbers possible. Arabic mathematicians encountered the Indian number system through translations of the Āryabhaṭīya and Brahmagupta's works and transmitted it to medieval Europe as the "Arabic numerals" — more accurately, the Indian numerals. Beyond the place-value system, the Āryabhaṭīya contains: the first correct value of π (approximately 3.1416, described as "approximate" — āsanna — with remarkable self-awareness); the correct explanation of solar and lunar eclipses through shadow geometry; the claim that the earth rotates on its own axis (revolutionary in 499 CE); trigonometric tables of sine values (jyā); and methods for solving linear and quadratic equations. Āryabhaṭa's astronomical calculations for the length of the sidereal year (365.25858 days) are accurate to within 3 minutes of the modern value.