Years ago, California Institute of Technology professor Konstantin Batygin was inspired to embark on a journey of discovering what lurked beyond Neptune. What he and his collaborator discovered was a strange field of debris.
This field of debris exhibited a clustering of orbits, and something was keeping these orbits confined. The only plausible source would be the gravitational pull of an extra planet—Planet Nine.
While Planet Nine hasn’t been found directly, the pieces of the puzzle are coming together. And Batygin is confident we’ll return to a nine-planet solar system within the next decade.