About five thousand years ago, in Bhagavad Gita it is said that the eternal existing principle can never be destroyed or decayed and the non existing can never be born. This principle is called 'law of conservation of energy' in the modern language. It means that energy is not wasted but is being converted. Such knowledge-science tradition has been going on in India since ancient times. Many visionary sages of the Vedic period were experts in mathematics and astronomy.
At a time when European countries had misconceptions about the universe and the earth was considered flat, students at Nalanda University in India in fifth century taught that the earth is round and revolves around its orbit.