There could be a ninth planet in our solar system that's lying in wait to be discovered - and no, it's not Pluto. Our solar ...

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 ...

Our Solar System has eight planets, a few dwarf planets and more than 200 moons. But wait. Are you seeing double? Or did ...

Are planets in the solar system that are closer to the Sun older than the ones further away? – Gavriel, age 10, Paducah, Kentucky A cloud of collapsing gas created our Sun, the first thing to form in ...

Pluto was reclassified as a dwarf planet in 2006. 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 ...