Hygiea isn’t a new discovery but the fact that it meets the International Astronomical Union’s (…

Pluto, Eris, Ceres, Makemake, Haumea, and five others meet Brown's "near certainty" criteria - in o…

They'll be using the Subaru telescope on the summit of Mauna Kea in Hawaii to hunt it down and sea…

NASA's Webb telescope was able to spot an object, the smallest of its kind, from 1,000 light years …

Stars die because they eventually burn through their reserves of hydrogen and helium. That fuel cre…

Narrator: And while these new worlds looked and behaved like Pluto, they were completely different …

When he discovered Pluto, Planet X became real - for a time. But in 2003, a world larger than Pluto…

"We feel exhilarated," Chris Russell, principal investigator of the Dawn mission at the University …

They also want to investigate why the dwarf planet is spewing jets of water vapor into space - a di…

This is made possible by its ion propulsion system, which gave the spacecraft enough power to escap…

Even from one million miles away, New Horizons was snapping photos (shown below) that were already …

The researchers don't know if life could exist on such a planet, though, because being closer to yo…

You can see the haze of Pluto's thin atmosphere circling the planet and, in the top of the sunlit p…

Mysterious brown dwarfs are neither planets nor stars, but this one somehow has northern lights, me…

"But one thing is certain: in a few billion years, when the Sun has run out of fuel and the Solar S…