 Since 1992, a very large number of objects have been found beyond Neptune; all the objects in the following list, however, are purely fictional.Common names for trans-Neptunian planets in fiction include Planet X, after a planet once believed to lie beyond Neptune, Persephone (or Proserpina), after the wife of Pluto, and Minerva, after the Roman goddess of wisdom and education (which would fit with a planet discovered through mathematical predictions rather than direct observation).Rogue planets in fiction usually originate outside the Solar System, but their erratic paths lead them to within detectable range of Earth.