Aryabhatta was a fifth century mathematician, astronomer, astrologer and physicist. He was a pioneer in the field of mathematics. At the age of 23, he wrote Aryabhattiya, which is a summary of mathematics of his time. There are four sections in this scholarly work.
In the first section he describes the method of denoting big decimal numbers by alphabets. In the second section, we find difficult questions from topics of modern day Mathematics such as number theory, geometry, trigonometry and Beejganita (algebra). The remaining two sections are on astronomy.
Aryabhatta showed that zero was not a numeral only but also a symbol and a concept. Discovery of zero enabled Aryabhatta to find out the exact distance between the earth and the moon. The discovery of zero also opened up a new dimension of negative numerals. As we have seen, the last two sections of Aryabhattiya were on Astronomy. Evidently, Aryabhatta contributed greatly to the field of science, too, particularly Astronomy. In ancient India, the science of astronomy was well advanced. It was called Khagolshastra. Khagol was the famous astronomical observatory at Nalanda, where Aryabhatta studied. In fact science of astronomy was highly advanced and our ancestors were proud of it. The aim behind the development of the science of astronomy was the need to have accurate calendars, a better understanding of climate and rainfall patterns for timely sowing and choice of crops, fixing the dates of seasons and festivals, navigation, calculation of time and casting of horoscopes for use in astrology. Knowledge of astronomy, particularly knowledge of the tides and the stars, was of great importance in trade, because of the requirement of crossing the oceans and deserts during night time. Disregarding the popular view that our planet earth is Achala (immovable), Aryabhatta stated his theory that earth is round and rotates on its own axis He explained that the appearance of the sun moving from east to west is false by giving examples. One such example was: When a person travels in a boat, the trees on the shore appear to move in the opposite direction. He also correctly stated that the moon and the planets shined by reflected sunlight. He also gave a scientific explanation for solar and lunar eclipse clarifying that the eclipse were not because of Rahhu and/or Ketu or some other rakshasa (demon,). Do you realize now, why the first satellite sent into orbit by India has been named after Aryabhatta?