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.

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 ...

In a distant region of space thought to be empty, a newly discovered dwarf planet inspires a debate about the existence of a giant planet hiding out there.

The object is about 700 kilometres wide and lies nearly three times farther from Earth than Neptune. Its highly elongated ...

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

It is an evocative idea: a huge and mysterious planet is lurking in the darkness at the edge of our solar system, evading all ...

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

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

A US-based trio hunting this elusive world has stumbled on what appears to be a new dwarf planet in the solar system's outer ...