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 ...

I/ATLAS interstellar comet or alien spacecraft? NASA released new images of comet 3I/ATLAS after a rare flyby near Earth. Scientists explain what the object is, how to see it today, and why it matters ...

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 ...