Astronomers propose a new hypothetical planet, Planet Y, beyond Neptune, based on observed orbital anomalies in the Kuiper ...

Astronomers have picked up evidence of an Earth-sized world, distinct from the previously hypothesised Planet Nine and Planet ...

Almost 20 years after Pluto was infamously downgraded from its status as a planet, scientists now believe they have discovered a new planet in our solar system.

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 ...

This new dwarf planet may exist at the edge of the solar system, possibly disproving Planet Nine's existence. This is the story of that newly encountered planet.

A team of astronomers believe they may have discovered a new dwarf planet—just like Pluto—on the edge of our solar system. The object—which orbits out beyond Neptune—has been named "2017 ...