Astronomers have hoped for the existence of Planet Nine for years. Things were looking promising, but this discovery might ...

Researchers use the Subaru Telescope in Hawaii to find a small object on the outer edge of the Solar System. Nicknamed ...

How many dwarf planets are there in our solar system? The recent discovery of 2017 OF201 makes the tally anywhere between ...

If Planet Nine is finally discovered, as one of those who first postulated its existence, does Brown have any suggestions for a possible formal name for this new member of the solar system?

New research shows there is at least a 40% chance of the existence of Planet Nine, but scientists are still looking for definitive proof.

The small world was found during a search for the hypothetical Planet Nine, and astronomers say the next time it will reach its closest point to the sun is in the year 26186.

Only eight planets call our solar system home. Or there might still be nine if some astronomers are correct about an as-yet undiscovered large body out past Neptune.

After a decade-long search, some scientists say a growing number of clues point to the existence of a hidden planet in the Kuiper Belt beyond Neptune — and they may soon have the opportunity to ...

In searching for the elusive Planet Nine, researchers instead turned up a different resident in our cosmic backyard.

Researchers from Rice University claim to have fresh evidence of Planet Nine - as well as a method to find it.

But even if it doesn't spot Planet 9 directly, the Rubin Observatory might find some more minor planets, ones whose orbits might be affected by Planet 9.

After a decade-long search, some scientists say a growing number of clues point to the existence of a hidden planet in the Kuiper Belt beyond Neptune — and they may soon have the opportunity to ...