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
Extraterrestrial liquid water vapour and could be indicators of liquid water deeper down. It could also be just ice. In June 2009, evidence was put forward for salty subterranean oceans on Enceladus. On April 3, 2014, NASA reported that evidence for a large underground ocean of liquid water on Enceladus, moon of planet Saturn, had been found by the Cassini spacecraft. According to the scientists, evidence of an underground ocean suggests that Enceladus is one of the most likely places in the solar system to "host microbial life". Emissions of water vapor have been detected from several regions of the dwarf planet Ceres.