There have been questions about a mysterious ninth planet in our solar system for nearly a decade. Pluto was unseated as number nine in 2006. Now, a group of international researchers say they may ...

For decades, our solar system was thought to have nine planets, with Pluto considered the smallest and farthest. But in 2006, Pluto was officially reclassified as a dwarf planet by the International ...

For years, astronomers have been searching for a ninth planet in our solar system (after giving Pluto the old heave-ho and demoting it to a dwarf planet) and now researchers say they've found a ...

Our solar system may have a ninth planet after all, researchers say. The possibility that an additional planet may be hidden far into the solar system was touted more than a century ago. But ...

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 ...

LONDON — 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 ...