Brown says he couldn't have asked for a better telescope to hunt his celestial quarry. "If you were to hand me a big wad of cash and say, 'Go build a telescope to go either find this Planet 9 or ...

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

In searching for the elusive Planet Nine, researchers instead turned up a different resident in our cosmic backyard. A composite image of the five dwarf planets recognized by the International ...

Planet Nine is a hypothetical planet, first theorised by astronomers from California Institute of Technology (Caltech) back in 2016. Said to have a mass about five to 10 times that of Earth, this ...

U.S. astronomers hunting for "Planet Nine" have instead stumbled on what appears to be a new dwarf planet in the solar system's outer reaches.

Scientists at the Institute for Advanced Study in Princeton, New Jersey, discover a new trans-Neptune Object, 2017OF201, potentially discrediting 2016 theory of Planet Nine.

With such an orbit, the possible planet could not explain the unusual clustering of Kuiper Belt objects that led to the prediction of Planet Nine. “Whether it is real or not, it is 100 percent ...

If Planet 9 is real, this observatory has around a 70 to 80 percent chance of finding it, he estimates, adding that it's not a sure thing because there are so many uncertainties.

That will allow the observatory to detect anything that changes — like, say, Planet Nine moving across the sky. "If it's there, we should be able to find it, pretty easily," says Blum.

That will allow the observatory to detect anything that changes — like, say, Planet Nine moving across the sky. "If it's there, we should be able to find it, pretty easily," says Blum.