Scientists believe our solar system may be hiding a secret world — and it’s not the famous Planet X :eyes: A new study ...

A rare discovery beyond Neptune is forcing scientists to rethink early solar system dynamics and the forces that shaped ...

The Ghost of the Solar System: Why Can't We Find Planet 9? Deep in the outer reaches of our solar system, far beyond Neptune ...

There have been questions about a mysterious ninth planet in our solar system for nearly a decade. Pluto was unseated as number nine in 2006. Now, a group of international researchers say they may ...

Jupiter is already the biggest planet by far in our solar system, but new research suggests it was somehow once even larger than it is now. Twice as large, in fact. To put that into context, those ...

Planet Y is the latest in a series of hypothetical solar system planets that scientists have proposed in recent years, all with slightly different characteristics but collectively believed to be ...

Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky. The solar system suddenly has a new member. A new object ...

A Hidden Planet: The Missing Piece? To solve these puzzles, researchers have proposed the existence of an undiscovered Earth-like planet in the Kuiper Belt. In a recent study, Dr. Patryk Sofia Lykawka ...

Discover the only planet in our solar system that rotates clockwise. Learn why this 'rebel' planet spins backwards, how a ...

If the solar system does have a Planet Nine, it is a world that was bullied by its larger siblings, exiled to the far reaches of space and only rescued from oblivion thanks to the intervention of ...

A new Tatooine-like planet outside the solar system may orbit two failed stars, scientists reported Wednesday. Located about 120 light years away, the exoplanet appears to take an unusual path around ...

(CNN) — The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have ...