DENVER — Small but rowdy space rocks pushing and jostling one another may have created the unusual orbits some astronomers cite as the signature of the hypothesized "Planet Nine," a new study suggests ...

Rocky worlds larger than Earth are commonplace in the galaxy, and a few of them may even be habitable. Which poses an interesting question: How difficult would it be for aliens living on these ...

Impact history should be considered a key factor in the search for habitable Earth-like exoplanets. Southwest Research ...

"Super-Earth" planets are giant-size versions of Earth, and some research has suggested that they're more likely to be habitable than Earth-size worlds. But a new study reveals how difficult it would ...

Super-Earths have been seen as planets that have the potential to host alien life. These types of planets are more common than Earth. There is just one problem with Super-Earths: gravity. Stronger ...