Editing Natural satellite (section)

==Geological activity==
Of the nineteen known natural satellites in the Solar System that are large enough to be gravitationally rounded, several remain geologically active today. [[Io (moon)|Io]] is the most volcanically active body in the Solar System, while [[Europa (moon)|Europa]], [[Enceladus]], [[Titan (moon)|Titan]] and [[Triton (moon)|Triton]] display evidence of ongoing [[Tectonics|tectonic activity]] and [[Cryovolcano|cryovolcanism]]. In the first three cases, the geological activity is powered by the [[Tidal heating#Tidal heating|tidal heating]] resulting from having [[orbital eccentricity|eccentric orbits]] close to their giant-planet primaries. (This mechanism would have also operated on Triton in the past before its orbit was [[tidal circularization|circularized]].) Many other natural satellites, such as Earth's Moon, [[Ganymede (moon)|Ganymede]], Tethys, and Miranda, show evidence of past geological activity, resulting from energy sources such as the [[Radioactive decay|decay]] of their [[Primordial nuclide|primordial]] [[Radionuclide|radioisotopes]], greater past orbital eccentricities (due in some cases to past [[orbital resonance]]s), or the [[Planetary differentiation|differentiation]] or freezing of their interiors. Enceladus and Triton both have active features resembling [[geysers]], although in the case of Triton solar heating appears to provide the energy. Titan and Triton have significant atmospheres; Titan also has [[lakes of Titan|hydrocarbon lakes]]. All four of the Galilean moons have atmospheres, though they are extremely thin.<ref>{{Cite web |url=https://www.planetary.org/blogs/emily-lakdawalla/2015/04081101-a-moon-with-atmosphere.html |title=A moon with atmosphere {{!}} The Planetary Society |access-date=24 December 2019 |archive-date=24 December 2019 |archive-url=https://web.archive.org/web/20191224075248/https://www.planetary.org/blogs/emily-lakdawalla/2015/04081101-a-moon-with-atmosphere.html |url-status=live }}</ref><ref name="EuropaAtmosphere">{{Cite web |title=Hubble Finds Oxygen Atmosphere on Jupiter's Moon, Europa |url=http://hubblesite.org/contents/news-releases/1995/news-1995-12 |access-date=2022-05-13 |website=HubbleSite.org |language=en |archive-date=16 April 2023 |archive-url=https://web.archive.org/web/20230416151919/https://hubblesite.org/contents/news-releases/1995/news-1995-12.html |url-status=live }}</ref><ref name="JPLAtmosphere">{{cite web |archive-url= https://web.archive.org/web/20090504072525/http://www2.jpl.nasa.gov/galileo/hst7.html |url= http://www2.jpl.nasa.gov/galileo/hst7.html|title=Hubble Finds Thin Oxygen Atmosphere on Ganymede |work=Jet Propulsion Laboratory |publisher=NASA |date=October 23, 1996 |access-date= February 17, 2017|url-status= dead |archive-date= May 4, 2009}}</ref> Four of the largest natural satellites, Europa, Ganymede, [[callisto (moon)|Callisto]], and Titan, are thought to have subsurface oceans of liquid water, while smaller Enceladus also supports a global subsurface ocean of liquid water.