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?
Since the first SETI experiment in 1960, astronomers have scanned the Milky Way for signs of advanced extraterrestrial civilizations. These searches have covered radio waves, optical flashes, and infrared heat signatures.
So far, they have found nothing confirmed. That silence is often explained by saying we have only searched a tiny part of the cosmic landscape. But what if signals did reach Earth and slipped past us?









