A newly discovered warp in the outer Solar System may have been created by a small, rocky world, much closer to the Sun than ...

On August 24, 2006, our solar system lost a planet. It wasn't by cataclysmic destruction, but rather by the vote of the International Astronomical Union, which declared that Pluto, considered the ...

A new study suggests yet another theory for a possible extra planet in our solar system, likely of a size between Mercury and ...

The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have dubbed ...