A new study has proposed the existence of Planet Y, an alternative Planet Nine candidate that is smaller and closer to Earth than the hypothetical Planet X, which astronomers have been hunting for ...

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 ...

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 ...

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 ...

A new study suggests yet another theory for a possible extra planet in our solar system, likely of a size between Mercury and ...

In 2006, updated research led to Pluto being controversially demoted to dwarf planet status by the International Astronomical Union. The reasoning was that Pluto's location in the far-flung ...

(CNN) — You might have a replacement, Pluto. There could be another planet in our solar system. Researchers at the California Institute of Technology have found evidence in the outer solar system of ...

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 ...

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 ...

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 ...