This icy world, temporarily named 2017 OF201, could be a distant cousin of Pluto — and scientists mean "distant" quite ...

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

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

Astronomers have discovered a mysterious dwarf planet, 2017 OF201, far beyond Pluto. This discovery challenges existing ...

Scientists believe such an extreme orbit means the object was pushed and pulled by the gravity of giant planets like Jupiter ...

Scientists have discovered a mysterious new object far beyond Neptune, and it could be one of the most distant dwarf planets ...

Scientists are intrigued after spotting a highly unusual celestial object lurking at the very edge of our solar system.

There’s a new frozen oddball orbiting the Sun, and it’s not your average space rock. It’s a planet—a minor one, to be ...

Astronomers find evidence of a possible ninth planet beyond Neptune, reigniting the debate about the formation of the Solar ...

Cheng, together with graduate students from Princeton University, discovered the potential dwarf planet while searching for ...