Scientists may have discovered a dwarf planet far beyond Neptune — an unearthing that may disprove a longstanding theory about the possibility of a giant ninth planet. The dwarf planet's existence ...

Spotting 2017 OF201 beyond the Kuiper Belt, a donut-shaped section of space past the orbit of Neptune filled with icy debris, suggests the region may not be as empty as previously thought.

Cheng said the discovery of 2017 OF201 has implications for hypotheses involving the potential existence of a ninth planet in our solar system, dubbed Planet X or Planet Nine.

The object, named 2017 OF201, is a minor planet — one of the largest found in nearly a decade. At an estimated 700 kilometers wide, it’s likely large enough to qualify as a dwarf planet. Its ...

While further observations are required to determine its exact size, current estimates suggest that 2017 OF201 is the second-largest known object in such a wide orbit.

Scientists have discovered a new dwarf planet candidate far beyond Pluto in the solar system. Its existence could mean there's no Planet 9.

Cheng said the discovery of 2017 OF201 has implications for hypotheses involving the potential existence of a ninth planet in our solar system, dubbed Planet X or Planet Nine.

2017 OF201 isn’t the planetary heavyweight many have been waiting for, but it’s a reminder that the solar system is still full of surprises—especially in its frigid, hard-to-see suburbs.

Learn about the recently discovered trans-Neptunian object that may eventually join Pluto as a dwarf planet, found at the edge of our solar system.