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

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

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

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

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

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

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

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

Plus, an in-depth look at how the West Texas city of Seminole reacted when a measles outbreak tore through the region.

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 ...

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

Some astronomers say the strange, clustered orbits of icy rocks beyond Neptune indicate that something big is out there, ...