The newcomer replacing Pluto presently goes by “Planet Nine.” If and when it finally shows up, it will get the honor of a ...

Worlds will align for a "planetary parade" in January, with four bright and easily visible to the naked eye. But an even ...

A new theory about Pluto’s largest moon, Charon, could alter how planetary systems are taught in U.S. schools. Scientists ...

“Because Pluto is rotating rapidly prior to the collision, and because Charon lies mostly outside of their corotation zone, ...

Pluto and Charon are in a region of the outer solar system beyond Neptune called the Kuiper belt, which makes them both rocky ...