Fictional planets of the Solar System a "tenth planet". 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, and Persephone (or Proserpina), after the wife of Pluto. Rogue planets in fiction usually originate outside the Solar System, but their erratic paths lead them to within detectable range of Earth. In reality, no rogue planet has ever been detected transiting the Solar System. Fictional planets of the Solar System The fictional portrayal of
Formation and evolution of the Solar System have been forged from the remnants in less violent collisions. Moons around some asteroids currently can only be explained as consolidations of material flung away from the parent object without enough energy to entirely escape its gravity. Moons have come to exist around most planets and many other Solar System bodies. These natural satellites originated by one of three possible mechanisms: Jupiter and Saturn have several large moons, such as Io, Europa, Ganymede and Titan, which may have originated from discs around each giant planet in much the same way that the planets formed from the disc around the Sun.