Tag: traces

If smart aliens exist, they may have visited Earth millions of years ago and left signs of their technological prowess that should be cheap and easy for us to detect.

So says astrophysicist Paul Davies of Arizona State University in Tempe.
Traditionally, the search for extraterrestrial intelligence (SETI) has focused on listening for deliberate dispatches in radio signals.
But in 50 years of searching, this costly approach has drawn a blank.