** Aryabhata worked on the approximation of value of pi () and came to the conclusion thatis irrational and is approximately 3.1416 in 499 CE when he was 23 years old.**

**He can be considered as one of the smartest brains of ancient India because because the irrationality of pi was proved in Europe only in 1761 by Lambert.**

**Not to mention, he even derived the values of sine & cos and gave birth to the concept of trigonometry.**

9. THEY THEORIZED THAT EARTH IS A SPHERE.

**Although the discovery of Earth being round is credited to Greek astronomers . Interestingly, Indian astronomers had already claimed that Sun is a star and that earth is spherical long before the Greeks. It is documented that various attempts had been made to measure the circumference of earth during the Vedic periods. Aryabhatta deduced a formulation which proves that the Earth is rotating on an axis. By estimating the value of pi to be 3.1416 he deduced the circumference of earth to be 39736 Kilometers which is only 100 kilometers below its true value.
In fact, in his book Aryabhatiya, he also asserts that the movement of heavenly bodies like the sun, the stars are all relative, and only earth is moving.
“Just as a passenger in a boat moving downstream sees the stationary (trees on the river banks) as traversing upstream, so does an observer on earth see the fixed stars as moving towards the west at exactly the same speed (at which the earth moves from west to east.”**