For the first time since Pluto was demoted, the idea of a true ninth planet is edging from speculation toward something ...

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 ...

There could be a ninth planet in our solar system that's lying in wait to be discovered - and no, it's not Pluto. Our solar ...

The solar system may have a ninth planet after all. This one is 5,000 times bigger than outcast Pluto and billions of miles farther away, say scientists who presented "good evidence" for a ...

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 ...

Astronomers searching for a ninth planet in our solar system say they've found a "good" candidate far beyond Neptune, according to a new preprint study. This could be humanity's first glimpse at the ...

After studying thousands of computer simulations of the solar system, researchers at Rice University and the Planetary Science Institute think there’s a 40% chance an elusive “Planet Nine” or “Planet ...

CAPE CANAVERAL, Fla. — The solar system may have a ninth planet after all. This one is 5,000 times bigger than outcast Pluto and billions of miles farther away, say scientists who presented “good ...

LONDON — The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper's authors have ...

Caltech professor Mike Brown (L) and assistant professor Konstanin Batygin have been working together to investigate distant objects in our solar system for more than a year and a half. The two ...