Detective astronomers have discovered at least one unseen alien planet, and possibly another, around a distant star by observing the odd behavior of a planet already known to orbit the same star. The ...

Mars. From forming black holes to phantom dark energy, discover the cosmic mysteries astronomers uncovered last year.

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 ...

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 ...