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

A ninth planet the size of Neptune may be hidden in the far reaches of the solar system, but the evidence has left some experts skeptical.

Some experts remain unconvinced about this discovery. It’s been almost two decades since our solar system lost its 9th planet. Pluto was officially reclassified from a planet to a dwarf planet ...

The NASA New Horizons spacecraft's extensive observations of Lyman-alpha emissions have resulted in the first-ever map from the galaxy at this important ultraviolet wavelength, providing a new look at ...

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.

For years, astronomers have been searching for a ninth planet in our solar system (after giving Pluto the old heave-ho and demoting it to a dwarf planet) and now researchers say they’ve found a ...

There have been questions about a mysterious ninth planet in our solar system for nearly a decade. Pluto was unseated as number nine in 2006. Now, a group of international researchers say they may ...

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

Once the quirky underdog of our solar system, Pluto held planetary status until 2006, when it got a cosmic demotion that still stings space fans. Discovered in 1930, Pluto was the ninth planet for ...