Alien civilizations may have left traces. We just may not have been looking in the right place.

Harvard physicist Avi Loeb said aliens would likely be disappointed by humanity's obsession with conflict. 'If I were looking at Earth from a distance, I would be pretty disappointed,' Loeb said. He ...

Aliens could, in theory, reach Earth but would never truly go home again, according to physicists who say Einstein's laws of relativity turn any near‑light‑speed visitor into a 'time exile.' The ...