Add Yahoo as a preferred source to see more of our stories on Google. Digital art of distant planet - Dottedhippo/Getty Images On August 24, 2006, our solar system lost a planet. It wasn't by ...

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 ...

Scientists say they finally have "solid evidence" for "Planet X" or "Planet 9." NASA/ESA/Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration via AP The solar system may have a ninth planet after all ...

There's a new object in the distant reaches of our solar system, and it might just offer clues to a long-standing cosmic mystery. Astronomers have cataloged a frozen minor planet called 2017 OF201, ...

This artistic rendering provided by California Institute of Technology shows the distant view from Planet Nine back towards the sun. The planet is thought to be gaseous, similar to Uranus and Neptune.

A recent research paper suggests that a planet may exist far beyond Neptune — less than 20 years after the previous ninth planet, Pluto, was demoted. That research paper, accepted last month for ...

CAPE CANAVERAL, Fla. – Scientists reported Wednesday they finally have “good evidence” for Planet X, a true ninth planet on the fringes of our solar system. The gas giant is thought to be almost as ...

On August 24, 2006, our solar system lost a planet. It wasn't by cataclysmic destruction, but rather by the vote of the International Astronomical Union, which declared that Pluto, considered the ...

Scientists reported Wednesday they finally have “good evidence” for Planet X, a true ninth planet on the fringes of our solar system. The gas giant is thought to be almost as big as Neptune and ...

Scientists reported Wednesday they finally have "good evidence" of Planet X, a true ninth planet on the fringes of our solar system. The gas giant is thought to be almost as big as Neptune and ...