What if mankind is looking for alien intelligent life that is already extinct? Astronomy professor Jason Wright from Penn State argues that the reason why humans can't find extraterrestrial life is because they no longer exist.

Wright published a paper that aims to address the issue of whether or not humans have searched hard enough for intelligent alien life. Currently, there is no evidence yet to prove that alien beings or extraterrestrials exist.

His work, "Prior Indigenous Technological Species," was published in the Cornell University's library under the Earth and Planetary Astrophysics. According to Wright's study, technosignatures might lead to the discovery of alien life forms or traces of it and it should be applied in the search outside the planet Earth.

"There is zero evidence for any prior indigenous technological civilizations," professor Wright said in an interview with Gizmodo. "My paper asks, have we completely foreclosed the possibility, or is there a chance that there could be some evidence we overlooked? [And] if we have overlooked something and we find it in the future, what are the chances it could have come from a prior indigenous technological species versus an interstellar one?"

The professor questions the effort put into the search for traces left behind by intelligent alien beings who could all be extinct today. Surprisingly, the professor is not an ardent believer of intelligent alien life or extraterrestrials. Reports say that he is merely presenting a part of what could be a thorough search for alien life forms.

He also added that traces of extinct alien life would be very difficult to find here on Earth due to tectonic movements, weather and other factors. However, other bodies outside the Earth capable of preserving data for millions of years might be holding traces of these being if they indeed lived. Some bodies have the condition and capabilities to protect its surface from solar radiations.

Searching for signs or materials that are not naturally formed can lead to the discovery of traces of extinct alien life. Wright concluded that the search for technosignatures should be initiated in and out of the planet in order to have a bigger chance of finding extraterrestrial life.