Astronomers have picked up evidence of an Earth-sized world, distinct from the previously hypothesised Planet Nine and Planet ...

New discoveries of objects in the Kuiper Belt have also presented challenges for the Planet Nine theory. The latest is known ...

For years, astronomers have searched the outer reaches of our solar system for Planet 9, a theoretical planet that could ...

A new study suggests the existence of Planet Y. This hidden planet may be affecting the Kuiper Belt. The gravity of Planet Y could be causing a tilt in the orbits of some icy objects. Researchers ...

A lot of back and forth We have been debating about the existence of Planet Nine since Pluto was demoted. Researchers have debunked the theory multiple times, but we keep looking for evidence.

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.

Planet Nine should be detectable by that telescope. But it would require an adjustment in the planned observing protocol to extend the telescope’s survey farther north than planned, Brown says ...