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 warning lands just as the US government publishes hundreds of previously classified unidentified anomalous phenomena case files,

Humans have always been fascinated with space. We frequently question whether we are alone in the universe. If not, what does intelligent life look like? And how would aliens communicate? How could that work when we have no shared language? Well, consider ...