Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...

A new look through decades-old data has unveiled some of the most compelling evidence yet of a hidden ninth planet in the far ...

A 9th planet in our solar system might be found — and no, it’s not Pluto - Is there another planet out there? Researchers say ...

Scientists think they’ve detected a new planet beyond Neptune. Find out why experts believe 'Planet X' might support alien ...

For over a century, astronomers have wondered if there's an extra planet in our Solar System that we haven't been able to see ...

The presence of another planet in the solar system could explain the odd movements of some of the bodies in the Kuiper Belt.

The solar system consists of our star, the sun, and everything bound to it by gravity: the planets Mercury, Venus, Earth, ...

Pluto, which infamously lost its status as the ninth planet in 2006, is less than four billion miles away from the sun, sitting in the Kuiper Belt - a region in our solar system beyond Neptune ...

Pluto was previously considered to be the ninth planet in our solar system, but the new definition of a planet requires the celestial body to have enough gravity to clear its orbital path from ...