Mike Brown is convinced that beyond Neptune, at the far reaches of our solar system, there's an unseen giant planet. "This is the 5th largest planet in our solar system, lurking out there, waiting to ...

Studying the orbits of thousands of exoplanets shows that large planets tend to have elliptical orbits, while smaller planets tend to have more circular orbits. This split coincides with several other ...

WASHINGTON, April 22 (Reuters) - Astronomers have spotted a small rocky planet that orbits perilously close to its host star disintegrating as its surface is vaporized by stellar heat, trailed by a ...

— -- Goldilocks, like most fairy tales, offers children a lesson and a happy ending. Whether a Goldilocks planet offers astronomers something similar still hangs up in the air, with the story's ...

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labeled as planet X, prominent astronomers ...

WASHINGTON, April 18 (Reuters) - In a memorable image from the 1977 film "Star Wars," the young hero Luke Skywalker gazes at two suns setting above the horizon on his desert planet Tatooine.

Despite its unmemorable name, J2322-2650 is a strange system. A Jupiter-sized exoplanet orbits an energetic neutron star, which constantly bombards it with gamma rays. Now, a team of astronomers has ...

This illustration shows an exoplanet orbiting around two brown dwarfs –– objects bigger than gas-giant planets but too small to be proper stars. ESO/M. Kornmesser Astronomers have discovered a ...