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 ...

For the first time since Pluto was demoted, the idea of a true ninth planet is edging from speculation toward something ...

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 ...

No one has been more bullied than Pluto. For like 80 years it was considered a planet. And then, in 2006, out of nowhere, it ...

Pluto, discovered in 1930, was once considered the ninth planet in our solar system. In 2006, the International Astronomical Union reclassified Pluto as a dwarf planet because it doesn't meet all the ...

The James Webb Space Telescope (JWST) has discovered that a hazy sky over frozen Pluto is helping to cool the dwarf planet's atmosphere, while at the same time giving methane and other organic ...

(Correction: An earlier version of this story misstated how far Pluto is from the sun. The correct number is 3.7 billion miles.) What was discovered in Flagstaff, Arizona, and killed off in Prague? If ...

After studying thousands of computer simulations of the solar system, researchers at Rice University and the Planetary Science Institute think there’s a 40% chance an elusive “Planet Nine” or “Planet ...

NEW YORK -- Pluto was once a planet. Then, a dwarf planet. And as of last week, a plutoid. The fall from grace has teachers, parents and educational publishers struggling to keep up, while kids remain ...