For years, scientists have been scanning the icy outskirts of our Solar System for an unknown massive planet. The ...

Computer simulations show that planets could be flung out of the inner solar system, supporting the possible existence of a ...

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.

No telescope has basked in the night sky quite like the enormous new Vera Rubin Observatory. Here's what it could reveal ...

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

For the dwarf planet candidate, one trip around the sun takes over 24,000 years. Its orbit challenges a proposed path for a hypothetical Planet Nine.

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. And that could provide additional evidence ...

If Planet 9 is on the smaller side, dark, and really far away, he explains, "it's going to be on the edge of Vera Rubin detection, and Vera Rubin may not find it." ...