Astronomers used a telescope in Hawaii to find a new object on the outer edges of our solar system, helping to fuel evidence of a long-standing theory about Planet Nine, or Planet X. For years, ...

Pluto will complete its first orbit since 1930 in 2178, a historic 248-year space journey that spans generations of humans.

There may be a warp in the Kuiper Belt, possibly caused by “Planet Y” — a Mercury-to-Earth-sized world that orbits the sun way beyond the orbit of Neptune. Is there a mysterious “Planet Y” orbiting ...

Neptune’s largest moon, Triton, and the dwarf planet Pluto may have shared a common origin before being separated in the early solar system, an analysis of their composition suggests. Triton and Pluto ...

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, ...

The outer solar system begins where sunlight fades and distances stretch beyond everyday comprehension. This journey traces humanity’s exploration of Uranus, Neptune, and Pluto, revealing how extreme ...

Hundreds of people who love the little planet that was dissed, gather every year in the Arizona town where Pluto was ...