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

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

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

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

The TNO, which are described as minor planets that orbit the sun at a greater distance than Neptune, were found on the edge ...

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

Given the name 2017 OF201, the object falls into a category called trans-Neptunian objects that orbit the sun at a distance ...

A new dwarf planet discovery in the outer solar system is challenging the long-standing theory of a hidden giant planet ...

OF201 is incredibly lightweight on a cosmic scale. Scientists estimate its mass is about 20,000 times less than Earth’s and ...

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

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

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