It's an evocative idea that has long bedeviled scientists: a huge and mysterious planet is lurking in the darkness at the ...

U.S. astronomers hunting for "Planet Nine" have instead stumbled on what appears to be a new dwarf planet in the solar system ...

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

The small world was found during a search for the hypothetical Planet Nine, and astronomers say the next time it will reach ...

A newly identified dwarf planet, named 2017 OF201, has been discovered in the distant outer reaches of the solar system.

A potential new dwarf planet has been discovered in the outer reaches of the solar system, and its existence poses the ...

The TNO, which are described as minor planets that orbit the sun at a greater distance than Neptune, were found on the edge ...

For the unversed, "Planet Nine" is a hypothetical planet which is reportedly larger than Earth that is thought to orbit ...

As fascinating as bizarre signals from other planets can be—teaching us about earthquakes on Mars or auroras in the skies of ...

Less than 1% of this dwarf planet candidate's orbit is close enough to detect, which means astronomers are lucky to have ...

Scientists' hunt for a mysterious planet at the edge of our solar system might have turned up results. A US-trio appears to ...