Researchers say they found a curious dot on infrared images taken 23 years apart that seems to be moving in a manner consistent with a large, distant planet.

Discovered in 1930, Pluto was long considered our Solar System's ninth planet, but was unseated in 2006 after the discovery ...

The interior of asteroid Vesta has been shown not to be a protoplanet after all, meaning that new explanations for its origin ...