Once the quirky underdog of our solar system, Pluto held planetary status until 2006, when it got a cosmic demotion that still stings space fans. Discovered in 1930, Pluto was the ninth planet for ...

Earth has a newly-discovered neighbor in the solar system. But the heavenly body – possibly a dwarf planet à la Pluto – isn't a frequent visitor. Located beyond Neptune, its extreme orbit ...

Pluto sits far out in the Solar System, small and dim, moving at a pace that barely fits human timelines. It was found in ...

Scientists who argue for Pluto to be classified as a planet are getting more ammo for a debate that has raged over the last 15 years. A team of researchers published a study in the scientific journal ...

Pluto's discovery was widely celebrated, especially in the U.S. After all, it was the first planet discovered in the new world, and America needed the win in 1930. "I think because it was discovered ...

For the first time since Pluto was demoted, the idea of a true ninth planet is edging from speculation toward something testable. Instead of restoring Pluto, researchers are closing in on a different, ...

Pluto's days, though they drag on a bit at around 153 hours, are nothing compared to its years. Pluto's orbit takes 248 Earth ...

Pluto may be a “dwarf” planet, but it is still a planet. In 2006, the International Astronomical Union, responding to the discovery of several Pluto-like objects in the Kuiper Belt beyond Neptune, ...

Mike Brown is convinced that beyond Neptune, at the far reaches of our solar system, there's an unseen giant planet. "This is the 5th largest planet in our solar system, lurking out there, waiting to ...