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 ...

Our solar system now, once again, officially consists of only eight planets. Although largely debunked, speculation continued ...

Pluto, the king of the underworld, was the ancient Romans' embodiment of death itself. Known as Hades in Greek mythology, ...

A newly discovered warp in the outer Solar System may have been created by a small, rocky world, much closer to the Sun than ...

WASHINGTON >> Scientists have identified an object about 435 miles wide inhabiting the frigid outer reaches of our solar system that might qualify as a dwarf planet, spotting it as it travels on a ...

A composite image showing the five dwarf planets recognized by the International Astronomical Union, plus the newly discovered trans-Neptunian object 2017 OF201. The TNO is potentially large enough to ...

A new study suggests yet another theory for a possible extra planet in our solar system, likely of a size between Mercury and Earth. The authors dubbed it Planet Y.

Astronomers using the Hubble Space Telescope have uncovered the remains of a frozen, Pluto-like world being devoured by a distant white dwarf star.

Anyone hungry for the icy crunch of a Pluto -like body? No? Well, one nearby white dwarf is going all in on a Pluto-esque snack.