When sonar first picked up a massive, stair‑like object on the floor of the Baltic Sea, the image looked less like geology and more like a movie prop. The structure’s circular outline, sharp edges and ...

A team of astronomers claims to have sniffed out a “biosignature” in the atmosphere of a distant planet called K2-18b. But not everyone agrees that it signals life. An illustration shows what ...

Humans should look to planetary alignments outside of the solar system when searching for signatures of extraterrestrial communications, scientists say. The nascent search for radio transmissions from ...

The Search for Extraterrestrial Intelligence (SETI) focuses on finding technosignatures—potential signs of alien technology. If we look carefully, we might have a chance at detecting their ...