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

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

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

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

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

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 ...

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

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

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The discovery challenges the Planet Nine hypothesis, which suggests a massive, unseen planet is influencing the orbits of distant TNOs. While most extreme TNOs show a clustered pattern that supports ...

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