Evidence pointing toward the existence of an undiscovered ninth planet in the solar system may actually indicate our ideas of gravity are incorrect. Such is the conclusion of two scientists who ...

Gravity is a fundamental force of physics, one which we Earthlings tend to take for granted. You can't really blame us. Having evolved over the course of billions of years in Earth's environment, we ...

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 ...

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 ...

Centuries before anyone pointed a telescope at the sky, Isaac Newton figured out how gravity works. He showed that any object ...

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 ...

Planets that go rogue orbit no star. They wander the vacuum of space alone, having been kicked out of their star systems by gravitational interactions with other planets and stars. Nobody really knows ...