Over the past decade, researchers have been puzzling through Pluto’s mysteries. Meanwhile, the New Horizons probe heads for interstellar space.

How many dwarf planets are there in our solar system? The recent discovery of 2017 OF201 makes the tally anywhere between ...

"By declaring that Pluto was no longer a planet, the (International Astronomical Union) put into place a planetary definition that would have even declassified Earth as a planet if it existed as ...

For the better part of a century, we believed there were nine planets in our solar system, with Pluto being the farthest from the sun. Since the discovery of more Pluto-sized dwarf planets, that ...

Ceres, Eris, Makemake, Haumea, and Pluto are expected to have a new friend, Hygiea, inducted into our solar system’s dwarf planet club. Hygiea was long believed to be a large asteroid in the ...

Pluto was once thought to be as big as the Earth. It was regarded as a full-fledged planet for three-quarters of a century, only to be demoted to a new category, "dwarf planet," in 2006.

Is Pluto a planet? No – Pluto is technically a dwarf planet and is classified differently than the major planets, which include Jupiter, Saturn, Uranus, Neptune, Earth, Venus, Mars and Mercury.

Distant starlight has given astronomers the best look yet at a distant icy sibling of Pluto, a dwarf planet called Makemake that appears to be missing its atmosphere, researchers say.Although this ...

In the time Pluto was found, classified as a planet and reclassified as a dwarf planet, it has not completed one orbit. One year on the distant ice planet is 248 Earth years, and one day is 153 ...

Dwarf planet Haumea reaches both opposition and perigee on April 20, making this a prime opportunity to see the dwarf planet in the night sky.

Researchers have long wondered if the little dwarf planet could be the home for some form of life. It's almost difficult, but not entirely impossible according to some. We're not talking about ...

Officially, Pluto is still not a planet. But five years after the ruling that demoted the icy object to dwarf planet, people continue struggling with the definition, and the debate over what ...