Ten of the alien worlds that represent our best hope for alien life beyond the solar system, according to the University of Puerto Rico at Arecibo.| Space
Nearly 2,000 planets have been found beyond our solar system, and some of them are quite strange. Space.com has images of the strangest alien planets discovered so far.| Space
Thousands of exoplanets have been discovered since the 1990s, including "hot Jupiters," "super-Earths" and other types of alien worlds.| Space.com