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 ...

Simultaneously cooling Pluto while energizing atmospheric molecules to allow them to escape into space, Pluto's haze plays a ...

For the dwarf planet candidate, one trip around the sun takes over 24,000 years. Its orbit challenges a proposed path for a hypothetical Planet Nine.

New James Webb Space Telescope data reveal Pluto's high-altitude haze is a key driver of the climate on the dwarf planet, ...

As it orbits the sun once every 25,000 years, the celestial body 2017 OF201 travels beyond the Kuiper Belt into a region thought to be largely devoid of objects ...

A team of astronomers believe they may have discovered a new dwarf planet—just like Pluto—on the edge of our solar system.

OF201, the object belongs to the same all-star family as Pluto: dwarf planets. Its diameter, roughly 435 miles (700 km), is ...

For the unversed, "Planet Nine" is a hypothetical planet which is reportedly larger than Earth that is thought to orbit beyond Neptune.

As a result of the International Astronomical Union’s 2006 demotion of Pluto from planet to dwarf planet, our solar system now consists of eight planets, nine dwarf planets, 891 confirmed moons or ...