An icy object in perfect sync with Neptune reveals new details about planetary migration and unseen bodies far beyond the Kuiper Belt.

There are a lot of worlds beyond the orbit of Neptune. Some are dwarf planets, while many others are much smaller rocks ...

"It is possible that a planet once existed in the solar system but was later ejected, causing the unusual orbits we see today ...

There's more to the solar system beyond Pluto's orbit. Researchers have discovered a new dwarf planet nearly 7.5 billion miles away from the sun. Even more intriguing, the discovery suggests the ...

Since it’s so far from the sun an average of about 3.7 billion miles, the farthest planet in the solar system and because it’s the smallest, scientists thought Pluto’s gravity would not be ...

Pluto was discovered in 1930 in Arizona, but in 2006 scientists decided to cut Pluto from the planetary line up. Here is why Pluto isn't a planet.

There's more to the solar system beyond Pluto's orbit. Researchers have discovered a new dwarf planet nearly 7.5 billion miles away from the sun. Even more intriguing, the discovery suggests the ...

Though Pluto has formally been considered a dwarf planet for almost two decades, it still has many lessons left for planetary scientists — including hints about how the solar system formed.