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

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.

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 ...

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

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

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

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

This hypothetical world, known as Planet Nine, could be ten times the size of Earth, but no one has been able to find it — yet. Now, with the launch of the Vera C. Rubin Observatory in Chile ...

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 ...