The existence of "Planet Nine," a hypothetical planet in the outer solar system, is supported by indirect evidence such as the unusual clustering of orbits of extreme trans-Neptunian objects (ETNOs) ...

For decades, our solar system was thought to have nine planets, with Pluto considered the smallest and farthest. But in 2006, Pluto was officially reclassified as a dwarf planet by the International ...

Mike Brown is convinced that beyond Neptune, at the far reaches of our solar system, there's an unseen giant planet. "This is the 5th largest planet in our solar system, lurking out there, waiting to ...

Planet 9 may exist 42 billion miles away, influencing objects in the Kuiper Belt, and could be discovered with modern ...

Planet Nine, the undiscovered planet at the edge of the solar system that was predicted by the work of Caltech’s Konstantin Batygin and Mike Brown in January 2016, appears to be responsible for the ...

Astronomers Brown and Batygin have presented accumulating evidence supporting the existence of Planet Nine, a hypothesized planet in our solar system, based on the unusual orbital characteristics of ...

Astronomers used a telescope in Hawaii to find a new object on the outer edges of our solar system, helping to fuel evidence of a long-standing theory about Planet Nine, or Planet X. For years, ...

An elusive Earth-like planet in our solar system could finally be discovered within the next few years. Known as Planet Nine or Planet X, it is a hypothetical planet that has long been rumoured to ...

The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their ...