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

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 ...

Scientists have detected methane gas glowing faintly above Makemake, an icy dwarf planet smaller and farther than Pluto in space. Until now, Pluto was the only object that far out in the solar system ...

Scientists studying the interstellar object ‘Oumuamua have proposed that it may be a fragment from a Pluto-like planet beyond ...

When you buy through links on our articles, Future and its syndication partners may earn a commission. A composite image comparing the relative sizes of our solar system's known dwarf planets, ...

Planet Nine is believed to be between five and 10 times the mass of Earth and would be orbiting the sun far beyond Pluto, at around 550 times the distance between Earth and the sun. Scientists have ...

A dwarf planet nicknamed the Goblin has been discovered beyond Pluto, astronomers said Tuesday. Scott Sheppard of the Carnegie Institution for Science, one of the scientists who made the find, said ...