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

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

There’s a new object in the distant reaches of our solar system, and it might just offer clues to a long-standing cosmic ...

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

The International Astronomical Union’s Minor Planet Center, which catalogs new moons and other small bodies in the solar ...

The newly discovered object, named 2017 OF201, has a 25,000-year orbit and is believed to be a large contender for dwarf ...

Astronomers have discovered a new dwarf planet, named 2017 OF201, far beyond Pluto's orbit. It takes 25,000 years to orbit ...

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 ...

A new dwarf planet, discovered beyond Neptune and described as Pluto's 'cousin,' could void the hypothesis of a Planet X in ...

At the very edge of our solar system, beyond the grasp of Neptune and even past the icy sprawl of Pluto’s domain, a new ...

Astronomers have found a new minor planet beyond Pluto. This object, named 2017 OF201, is quite large. It orbits far from the ...