The newcomer replacing Pluto presently goes by “Planet Nine.” If and when it finally shows up, it will get the honor of a ...

There are eight official planets (sorry, Pluto) in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and ...

The potential discovery of a large planet beyond Neptune’s orbit could change everything we know about the Solar System.

NASA’s shocking claim hints at a hidden planet, possibly 10 times Earth's size, or a primordial black hole. Gravitational ...

In 2015, two astronomers from Caltech presented evidence that six objects past the orbit of Neptune were bunched ... better than in simulations where planet 9 was not included.

Astronomers are on the hunt for a mysterious ninth planet, known as Planet Nine, which could change our understanding of the solar system. Is this hidden world real, or just a myth?

Researchers seeking Planet Nine can then use the newly discovered ... Objects that cross Neptune’s orbit like that should get ejected from the solar system, so how can these objects on these ...

Astronomers are searching for a potential ninth planet, known as Planet Nine, which could reshape our understanding of ...

From the mysterious Planet Nine to the prospect of a "human-caused meteor shower," space and physics editor Brandon Specktor ...