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.

Scientists may have discovered a dwarf planet far beyond Neptune — an unearthing that may disprove a longstanding theory ...

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.

The chance of a planet forming in the outer reaches of the solar system – a hypothetical Planet Nine – could be as high as 40 ...

Discovery of 2017OF201, a large trans-Neptune Object, challenges previous beliefs about the Kuiper Belt and hints at the ...

But in recent years, astronomers have proposed that a ninth world, imaginatively nicknamed "Planet Nine," could be hiding in the far reaches of our cosmic neighborhood. And no, we're not talking ...

A possible new dwarf planet has been discovered at the edge of our solar system, so far-flung that it takes around 25,000 ...

Beyond the edge of Neptune, a distant realm of icy debris known as the Kuiper Belt stretches deep into space. This frozen ...

As it orbits the sun once every 25,000 years, the celestial body 2017 OF201 travels beyond the Kuiper Belt into a region ...

As a result of the International Astronomical Union’s 2006 demotion of Pluto from planet to dwarf planet, our solar system ...

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

With the demotion of Pluto in 2006, the idea of Planet Nine was first proposed in 2016 by astronomers Batygin and Brown. Its existence is inferred from the unusual orbital clustering of several ...