Billions of years ago, in the frozen edges of the solar system, a violent impact shaped one of space’s oddest pairs. Instead ...

A 9th planet in our solar system might be found — and no, it’s not Pluto - Is there another planet out there? Researchers say ...

Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...

New Horizons principal investigator Alan Stern says, "Pluto is showing us a diversity of landforms and complexity of processes that rival anything we've seen in the solar system." As the craft ...

A ninth planet the size of Neptune may be hidden in the far reaches of the solar system, but the evidence has left some experts skeptical.

Astronomers have detected a promising sign of a ninth planet lurking at the the farthest reaches of the Solar System.