First of all Hinduism is not a religion. It is a culture. The culture of GODS.(Also known as the sanadhana dharma) I believe that Hinduism is following the culture of that alien race.(Which are still follow today). The conflict between devas and asuras as depicted in geetha and other religious texts may depict two conflicting alien races coming to earth for dominance.(Reason still unknown). Evidences are all around us. Use our perceptive intelligence to understand them. For instance the brahmaasthra had properties of modern day nuclear bomb. Were these texts describing what our ancestors actually saw? since they didnt have technological knowledge of a nuclear bomb, they considered them to be a divine weapon of devas.
Indian Vedas and religious text of hinduism are a treasure house of knowledge. The above mentioned bhramasthra , is it actually a nuclear bomb in action? (Thousand of years before the discovery radioactivity)Do we have any evidences for that? Yes, we have! The answer to this mystery lies in the heart of india and hiduism "THE ANCIENT CITY OF MOHENJADARO"
Mohenjo-daro is an archeology site of one of the largest Indus Valley civilizations that thrived around 2000 BCE. Historians and archaeologists were stunned to see fossilized remains of human bones lying in streets holding hands. Does it shows that they were wiped off instantaneously by a nuke attack? still hard to digest? The studies in that area shows high levels of radiation (In par with Nagasaki and Hiroshima cities). The rock structures were literally turned to glass. This process is possible only due to immense temperature as during a nuke explosion.!
Other evidences in VEDAS include references to ADVANCED SCI-FI Technologies including Vimanas-Flying machines : See Ancient Indian VIMANAS