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 ...

Add Yahoo as a preferred source to see more of our stories on Google. Our solar system may have a ninth planet after all, researchers say. The possibility that an additional planet may be hidden far ...

What is Planet Nine, and where is it? The question has fascinated astronomers for years. Scientists believe a massive undiscovered planet may exist in the outer Solar System. Although no telescope has ...

The hunt for Planet Nine continues as new discoveries make the Solar System’s biggest mystery even harder to solve. Is there ...

In an exciting breakthrough in planetary science, a recent study has increased the likelihood of Planet Nine’s existence by up to 40%. This planet, also referred to as Planet X, has remained an ...

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 ...

With the same data but a different statistical analysis, researchers have spotted two additional planets in a system that was already thought to host seven of them ...

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labeled as planet X, prominent astronomers ...

A newly discovered object orbiting far beyond Neptune has its closest approach to the Sun pointed in the opposite direction from every other known body like it, weakening one of the central ...

Scientists may have discovered a dwarf planet far beyond Neptune — an unearthing that may disprove a longstanding theory about the possibility of a giant ninth planet. The dwarf planet's existence ...

Our solar system may have a ninth planet after all, researchers say. The possibility that an additional planet may be hidden far into the solar system was touted more than a century ago. But ...