Discovered in 1930, Pluto was long considered our Solar System's ninth planet, but was unseated in 2006 after the discovery ...

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

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

Researchers have found a candidate for the hypothetical Planet Nine, which could be an undiscovered giant planet way out in ...

Astronomer Eliza Kempton said that she had waited her "entire career" to peer into an atmosphere from this mysterious class of planets.

Discover the order of planets in the solar system. From Mercury to Neptune, explore our solar system and learn more about our cosmic home. The solar system is our cosmic neighborhood, made up of ...

Astronomers have long speculated about an unseen planet lurking in the solar system's outer edge. This hypothetical world, ...

Earth has four seasons, but do other planets in our solar system also have hot summer days and cold winter nights?

Astronomers have detected a promising sign of a ninth planet lurking at the the farthest reaches of the Solar System.

Pluto was discovered in 1930 in Arizona, but in 2006 scientists decided to cut Pluto from the planetary line up. Here is why ...

Astronomers may have found a candidate for Planet Nine. This planet is beyond Neptune. The finding could be the first ...