For years, astronomers have been searching for a mysterious ninth planet lurking in the dark outer reaches of our solar ...

In the remote outer reaches of planetary systems, far beyond the orbit of known planets, enormous and mysterious worlds ...

Close stellar encounters could change the structure of our planetary system, potentially dooming Earth or other worlds to ...

The study went on to note that a cause for the pulse could have been that it was struck by a small piece of space rock, known ...

Stars passing close to the sun could cause planets to collide, including with Earth, or even be ejected as rogue planets, new ...

Astronomers discovered that C/2014 UN271, a massive comet more than 10 times larger than any known comet, is emitting jets of ...

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.

A possible new dwarf planet has been discovered at the edge of our solar system, so far-flung that it takes around 25,000 years to complete one orbit around the sun. The object, known as 2017 ...

The new object, named 2017 OF201, was discovered by researchers in an astronomical image database while searching for trans-Neptunian objects (TNOs) and possible new planets in the outer solar system.

A team of astronomers believe they may have discovered a new dwarf planet—just like Pluto—on the edge of our solar system. The object—which orbits out beyond Neptune—has been named "2017 OF201" by the ...

Scientists at the Institute for Advanced Study in Princeton, New Jersey, discover a new trans-Neptune Object, 2017OF201, potentially discrediting 2016 theory of Planet Nine.