The world of Sailor Moon does not just relate to our own solar system, but the many unknown planets from the original story ...

Earth is our home planet, and it's the only place in the universe where we know for certain that life exists. Earth formed over 4.5 billion years ago from a swirling cloud of gas and dust squished ...

The nearest single star to the sun, Barnard’s star, has a brood of planets all its own. The red dwarf star, about six light-years from Earth, hosts four close-in planets each about two to three ...

Proctor/J. Pollard A quartet of Earth-like worlds, each about 20% to 30% the size of our planet, circle one of our closest stellar neighbors, a new study reveals. The rocky alien worlds are close ...

SEE ALSO: Stop describing a planet as 'Earth-like' unless it really is This marks the first time so many Earth-sized worlds have been found orbiting the same star. It's possible that some of those ...

A new study presents a compelling new model for the formation of super-Earths and mini-Neptunes -- planets that are 1 to 4 times the size of Earth and among the most common in our galaxy.