"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." If life can exist—and persist—in seclusion, and in some of the harshest conditions on Earth (just look at ...

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 ...

If advanced alien civilisations are building vast satellite swarms designed to harvest a star’s energy, we should be able to see them – so why haven’t we? One answer might be that these structures, ...