A new study may finally explain how planets can end up orbiting their stars at extremely large distances—sometimes hundreds ...

At least three city-killing asteroids that could strike Earth are hiding behind our closest neighbor in the solar system.

In the cold, dark outskirts of planetary systems far beyond the reach of the known planets, mysterious gas giants and ...

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

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

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

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 ...

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

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

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

Jupiter, roughly 562 million miles from Earth today, has nearly 100 moons. But Batygin and his collaborator Fred Adams' research focused on two of the smaller ones, Amalthea and Thebe. Both are inside ...