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 ...

Neptune’s supersonic winds and icy storms revealed a planet so extreme that it forever changed our picture of the solar system. The discovery of Neptune in 1846 was not just the triumph of mathematics ...

A newly discovered object speeding through our solar system is sparking excitement among astronomers because it’s not from around here. Believed to be a comet, the object is only the third celestial ...