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

A mysterious new world may be hiding in the outer reaches of our solar system. According to arecent study published on arXiv ...

Independent previous research has also proposed a similar Planet Y to explain the warp or other features in the TNO ...

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

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.

Using NASA's Chandra X-ray spacecraft, astronomers have witnessed a distant, Jupiter-size world "shrinking" as its host star bombards it with heavy radiation. The extrasolar planet, or "exoplanet ...

A possible dwarf planet, like Pluto, has been observed in our solar system, according to a preprint published in arXiv. The area of space where this planet was found was previously thought empty.