A strange purple object aboard the ISS sparked alien fears online, but NASA revealed it was a potato experiment. It shows how ...

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

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

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