Astronomers have detected a promising sign of a ninth planet lurking at the the farthest reaches of the Solar System.

sitting in the Kuiper Belt - a region in our solar system beyond Neptune filled with icy objects, comets, and dwarf planets like Pluto. Since this hidden planet may be so far away, the new study ...

Pluto was discovered in 1930 in Arizona, but in 2006 scientists decided to cut Pluto from the planetary line up. Here is why ...

Pluto remains a fascinating and beloved part of our solar system with a slightly less glamorous title. At this moment, Pluto is still classified as a dwarf planet. Despite ongoing debate and ...

Play the USA TODAY Daily Crossword Puzzle ... beloved part of our solar system with a slightly less glamorous title. At this moment, Pluto is still classified as a dwarf planet.