Astronomy in Ancient India
The practice of astronomy in ancient India is mentioned in Rig Veda which was composed about 4000 years ago.
Many Indian scholars have contributed to astronomy. One of the most well known astronomers is Aryabhata. The work of Aryabhata on astronomy can be found in his writing ‘Aryabhatiya’. He wrote it in 499 CE at the age of 23 years. The diameter of the Earth as stated by Aryabhata is close to its presently known value. Disregarding the popular view that Earth is ‘achala’ (immovable), Aryabhata stated that Earth is sphere and rotates on its own axis. His estimate about the sidereal period of Earth was 23 hours, 56 minutes and 4.1 seconds, which is very close to the presently known value. He also correctly stated that the moon and the planets shine due to reflected sunlight. He also gave a scientific explanation for solar and lunar eclipses. When the shadow of the Earth falls on the moon, it causes lunar eclipse. When the shadow of the moon
falls on the Earth, it causes solar eclipse. Aryabhata also found the distance between the Earth and the moon, which is very close to the known
value today.