In these science fiction books, extraterrestrial beings are sympathetic, horrifying and everything in between.

(cokada/iStock/Getty Images) Alien megastructures built to harvest stellar energy or alter the orbits of stars may be ...

Scientists have uncovered a surprising way to study the harsh space weather around young M dwarf stars. Mysterious dips in starlight turned out to be massive rings of plasma swirling in the stars’ ...

A strange purple object aboard the ISS sparked alien fears online, but NASA revealed it was a potato experiment. It shows how microgravity can turn ordinary plants into bizarre shapes.

Comet 41P/Tuttle-Giacobini-Kresak has begun acting a little unusually, but there are likely natural explanations before we go ...

A video, now viral on the social media, shows a bright object slowly falling from the sky over Indonesia, triggering claims ...

The third known visitor from another star system, Comet 3I/ATLAS, has been racing through the Solar System with just enough weirdness to ignite a familiar debate: is it natural or could it be ...

A strange, tentacled object that went viral online was revealed to be a space-grown purple potato. Astronaut Don Pettit ...

Trump has ordered a UFO data release. But if aliens exist, what would they think of us? - For generations, human beings have ...

Debunking alien claims matters, but so does telling richer, more compelling stories about how humans shaped their own past.