The small world was found during a search for the hypothetical Planet Nine, and astronomers say the next time it will reach ...

As it orbits the sun once every 25,000 years, the celestial body 2017 OF201 travels beyond the Kuiper Belt into a region ...

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

The object’s aphelion the farthest point on the orbit from the Sun is more than 1,600 times that of the Earth’s orbit,” said ...

A potential new dwarf planet has been discovered in the outer reaches of the solar system, and its existence poses the ...

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

A small team led by Sihao Cheng, Martin A. and Helen Chooljian Member in the Institute for Advanced Study's School of Natural ...

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

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

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 ...