While he didn't actually "discover" the concept of Earth's rotation in the modern scientific sense, he was the first to propose it as a theory in his book Aryabhatiya around 499 CE. He stated that the Earth spins on its axis, which is why we see the sun, moon, and stars moving across the sky.
It's important to note that this concept was not widely accepted at the time and was met with resistance. It was only much later that Copernicus and Galileo independently proposed the heliocentric model of the solar system, which solidified the understanding of Earth's rotation.
