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 ...

Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, researchers say. ABC News. Video. Live. Shows. Shop. Log In. Stream on.

Scientists may have discovered a dwarf planet far beyond Neptune — an unearthing that may disprove a longstanding theory ...

For the dwarf planet candidate, one trip around the sun takes over 24,000 years. Its orbit challenges a proposed path for a hypothetical Planet Nine.