# Contribution of Aryabhatta to Indian Science

Aryabhatta was the legendary mathematician of the Gupta Era. He wrote Aryabhattiya at the age of 23 years and later, Arya-Siddhanta. He worked on the approximation for pi to 3.1416. In trigonometry, he concluded for a triangle, the result of a perpendicular with the half-side is the area. He also worked on the motions of the solar system and calculated the length of the solar year to 365.8586805 days. Aryabhatta lived in Kusumpur in Pataliputra.

#### Contributions of Aryabhata (476 AD)

Aryabhata is the author Aryabhatiyam which sketches his mathematical, planetary, and cosmic theories. This book is divided into four chapters:

• The astronomical constants and the sine table
• Mathematics required for computations,
• Division of time and rules for computing the longitudes of planets using eccentrics and epicycles,
• The armillary sphere, rules relating to problems of trigonometry and the computation of eclipses.

Aryabhata took the earth to spin on its axis; this idea appears to have been his innovation. He also considered the heavenly motions to go through a cycle of 4.32 billion years; here he went with an older tradition, but he introduced a new scheme of subdivisions within this great cycle. According to the historian Hugh Thurston, Not only did Aryabhata believe that the earth rotates, but there are glimmerings in his system (and other similar systems) of a possible underlying theory in which the earth (and the planets) orbits the sun, rather than the sun orbiting the earth. The evidence is that the basic planetary periods are relative to the sun. That Aryabhata was aware of the relativity of motion is clear from this passage in his book “Just as a man in a boat sees the trees on the bank move in the opposite direction, so an observer on the equator sees the stationary stars as moving precisely toward the west.”

In his book named ‘Aryabhattium’, Aryabhatta has given lot of references of Suryasidhanta. He had developed instruments like chakra yantra (disk instrument), Gola yantra (type of armillary sphere) and shadow instruments.

Aryabhatta deduced that earth is a rotating sphere: the stars do not move, it is the earth that rotates. Its diameter is 1,050 yojanas. Its circumference is therefore 1050 x 13.6 x π = 44,860 km.

Aryabhatta also deduced that: “The moon eclipses the sun, and the great shadow of the earth eclipses the moon.”