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

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

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

A team of astronomers believe they may have discovered a new dwarf planet—just like Pluto—on the edge of our solar system.

The first observations of Pluto by NASA's James Webb Space Telescope (JWST) reveal dramatic phenomena on its surface, like ...

Almost 20 years after Pluto was infamously downgraded from its status as a planet, scientists now believe they have ...

A recently discovered celestial body is rewriting our knowledge of the Kuiper Belt and maybe challenging the existence of the ...

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

Scientists have identified an object about 435 miles (700 km) wide inhabiting the frigid outer reaches of our solar system that might qualify as a dwarf planet, spotting it as it travels on a highly ...

A new dwarf planet discovery in the outer solar system is challenging the long-standing theory of a hidden giant planet ...

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