Planet nine is a theory that thare a nint planet in the solar seestem. The idea haes its springheid in the orbits o different asteroids aboot the same aurie at the faur end o the solar seestem. Acause thare mony asteroids in orbit aboot, it is thocht tha the planet is a muckle ane, ten times the mass o the Yird an fower times its bouk. The theory wis first set furth on the 20t Januar 2016, efter the first work on it in 2014.

Artist's concept o Planet nine
Artist's concept o Planet nine