For decades, scientists have searched the skies for signs of extraterrestrial technology. A study from EPFL asks a sharp question: if alien signals have already reached Earth without us noticing, what should we realistically expect to detect today?

Astronomers have searched the skies for signs of extraterrestrial technology for decades. These searchers since 1960 have scanned the Milky Way for radio waves, optical flashes, infrared heat and other technological signatures indicative of advanced aliens.

Donald Trump wants the truth on extraterritorial life, at least, out there. The president on Thursday night directed government agencies to release files pertaining to the existence of aliens just hours after complaining that Barack Obama had shared classified information on the matter.