Planet 9 sits at the edge of scientific imagination, promising either an epic expansion of the Solar System or a lesson in ...

Far beyond Neptune, something heavy appears to be tugging on the outer solar system, bending the paths of distant icy worlds in ways gravity alone should be able to explain. Planet 9, still invisible ...

It's an evocative idea that has long bedeviled scientists: a huge and mysterious planet is lurking in the darkness at the edge of our solar system, evading all our efforts to spot it. Some astronomers ...

There has been a lot of back and forth about the existence of a mysterious ninth planet, often referred to as "Planet Nine" or even "Planet X." Now, though, researchers say there is likely at least a ...

After studying thousands of computer simulations of the solar system, researchers at Rice University and the Planetary Science Institute think there’s a 40% chance an elusive “Planet Nine” or “Planet ...

An artist's illustration of a possible ninth planet in our solar system, hovering at the edge of our solar system. Neptune's orbit is shown as a bright ring around the Sun. Scientists in Taiwan ...

Researchers have found a candidate for the hypothetical Planet Nine, which could be an undiscovered giant planet way out in our solar system. However, as with all ninth planet research, the new ...

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labeled as planet X, prominent astronomers ...

Ian Whittaker does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...