For the dwarf planet candidate, one trip around the sun takes over 24,000 years. Its orbit challenges a proposed path for a hypothetical Planet Nine.

Researchers found the object named 2017 OF201 while searching for "Planet Nine" - a hypothetical planet thought to exist ...

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

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

U.S. astronomers hunting for "Planet Nine" have instead stumbled on what appears to be a new dwarf planet in the solar system ...

For the unversed, "Planet Nine" is a hypothetical planet which is reportedly larger than Earth that is thought to orbit ...

Our solar system is the only one known to have life inside. While scientists are searching for water in other planets, a new ...

Almost 20 years after Pluto was infamously downgraded from its status as a planet, scientists now believe they have ...

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

Discover interesting facts about the sun, the solar system's central star that supports all life on Earth.

Scientists have discovered a colossal object approximately 435 miles wide in the frigid outer reaches of our solar system, ...