Geothermal energy is heat energy generated and stored in the Earth. Geothermal energy has been used for thousands of years in some countries for cooking and heating. It is simply power derived from the Earth's internal heat.
Ashtadhyayi was written by Panini. He was a Sanskrit grammarian who gave a comprehensive and scientific theory of phonetics, phonology, and morphology. Panini was born in Shalatula, a town near to Attock on the Indus river in present day Pakistan.