"Moons of Pluto The dwarf planet Pluto has five moons down to a detection limit of about 1 km in diameter. In order of distance from Pluto, they are Charon, Styx, Nix, Kerberos, and Hydra. Charon, the largest of the five moons, is mutually tidally locked with Pluto, and is massive enough that Pluto–Charon is sometimes considered a double dwarf planet. The innermost and largest moon, Charon, was discovered by James Christy on 22 June 1978, nearly half a century after Pluto was discovered. This led to a substantial revision in estimates of Pluto's size, which had previously assumed that"
"Triton (moon) Triton is the largest natural satellite of the planet Neptune, and the first Neptunian moon to be discovered. The discovery was made on October 10, 1846, by English astronomer William Lassell. It is the only large moon in the Solar System with a retrograde orbit, an orbit in the direction opposite to its planet's rotation. At in diameter, it is the seventh-largest moon in the Solar System. Because of its retrograde orbit and composition similar to Pluto's, Triton is thought to have been a dwarf planet captured from the Kuiper belt. It has a surface of mostly frozen"
"Titan (moon) Titan is the largest moon of Saturn. It is the only moon known to have a dense atmosphere, and the only object in space, other than Earth, where clear evidence of stable bodies of surface liquid have been found. Titan is the sixth gravitationally rounded moon from Saturn. Frequently described as a planet-like moon, Titan is 50% larger than Earth's moon and 80% more massive. It is the second-largest moon in the Solar System after Jupiter's moon Ganymede, and is larger than the smallest planet, Mercury, but only 40% as massive. Discovered in 1655 by the Dutch astronomer"
"Kuiper belt objects. Though Pluto is the largest Kuiper belt object discovered, Neptune's moon Triton, which is slightly larger than Pluto, is similar to it both geologically and atmospherically, and is thought to be a captured Kuiper belt object. Eris (see above) is about the same size as Pluto (though more massive) but is not strictly considered a member of the Kuiper belt population. Rather, it is considered a member of a linked population called the scattered disc. A large number of Kuiper belt objects, like Pluto, are in a 2:3 orbital resonance with Neptune. KBOs with this orbital resonance"
"Callisto (moon) </math>.</ref> Callisto (Jupiter IV) is the second-largest moon of Jupiter, after Ganymede. It is the third-largest moon in the Solar System after Ganymede and Saturn's largest moon Titan, and the largest object in the Solar System not to be properly differentiated. Callisto was discovered in 1610 by Galileo Galilei. At in diameter, Callisto has about 99% the diameter of the planet Mercury but only about a third of its mass. It is the fourth Galilean moon of Jupiter by distance, with an orbital radius of about . It is not in an orbital resonance like the three other"
"recognition at some time in the future. Alan Stern of the Southwest Research Institute believes the outer planets show signs of collisions with plutoids 1,000 to 2,000 kilometers in diameter: Uranus could have been tipped off its axis by a plutoid, and Triton, the largest moon of Neptune, is probably a captured plutoid from the Kuiper belt. On 24 August 2006, the IAU decided to reclassify Pluto as a dwarf planet, requiring that a planet must ""clear the neighbourhood around its orbit"". The General Assembly of the IAU further resolved: This new category had been proposed under the name """"pluton"""""
"Jingpo Lacus Jingpo Lacus is a lake in the north polar region of Titan, the planet Saturn's largest moon. It and similarly sized Ontario Lacus are the largest known bodies of liquid on Titan after the three maria (Kraken Mare, Ligeia Mare and Punga Mare). It is composed of liquid hydrocarbons (mainly methane and ethane). It is west of Kraken Mare at 73° N, 336° W, roughly 240 km (150 mi) long, similar to the length of Lake Onega on Earth. Its namesake is Jingpo Lake, a scenic lake in China. On 8 July 2009, ""Cassini""'s Visual and Infrared Mapping"
"on the structure of the Kuiper belt. Neptune has 14 known moons. Triton is the largest Neptunian moon, comprising more than 99.5% of the mass in orbit around Neptune, and it is the only one massive enough to be spheroidal. Triton was discovered by William Lassell just 17 days after the discovery of Neptune itself. Unlike all other large planetary moons in the Solar System, Triton has a retrograde orbit, indicating that it was captured rather than forming in place; it was probably once a dwarf planet in the Kuiper belt. It is close enough to Neptune to be locked"
"Ganymede (moon) Ganymede (Jupiter III) is the largest and most massive moon of Jupiter and in the Solar System. The ninth largest object in the Solar System, it is the largest without a substantial atmosphere. It has a diameter of and is 8% larger than the planet Mercury, although only 45% as massive. Possessing a metallic core, it has the lowest moment of inertia factor of any solid body in the Solar System and is the only moon known to have a magnetic field. It is the third of the Galilean moons, the first group of objects discovered orbiting another"
"more than 99.5% of all the mass known to orbit Neptune, including the planet's rings and thirteen other known moons, and is also more massive than all known moons in the Solar System smaller than itself combined. Also, with a diameter 5.5% that of Neptune, it is the largest moon of a gas giant relative to its planet in terms of diameter, although Titan is bigger relative to Saturn in terms of mass. It has a radius, density (2.061 g/cm), temperature and chemical composition similar to those of Pluto. Triton's surface is covered with a transparent layer of annealed frozen"
"Titania (moon) Titania is the largest of the moons of Uranus and the eighth largest moon in the Solar System at a diameter of . Discovered by William Herschel in 1787, Titania is named after the queen of the fairies in Shakespeare's ""A Midsummer Night's Dream"". Its orbit lies inside Uranus's magnetosphere. Titania consists of approximately equal amounts of ice and rock, and is probably differentiated into a rocky core and an icy mantle. A layer of liquid water may be present at the core–mantle boundary. The surface of Titania, which is relatively dark and slightly red in color, appears"
"winds of any planet in the Solar System, measured as high as 2,100 km/h. ""Voyager 2"" also examined Neptune's ring and moon system. It discovered 900 complete rings and additional partial ring ""arcs"" around Neptune. In addition to examining Neptune's three previously known moons, ""Voyager 2"" also discovered five previously unknown moons, one of which, Proteus, proved to be the last largest moon in the system. Data from ""Voyager 2"" supported the view that Neptune's largest moon, Triton, is a captured Kuiper belt object. The dwarf planet Pluto presents significant challenges for spacecraft because of its great distance from Earth"
"Moons of Neptune Neptune has 14 known moons, which are named for minor water deities in Greek mythology. By far the largest of them is Triton, discovered by William Lassell on October 10, 1846, 17 days after the discovery of Neptune itself; over a century passed before the discovery of the second natural satellite, Nereid. Neptune's outermost moon Neso, which has an orbital period of about 26 Julian years, orbits further from its planet than any other moon in the Solar System. Triton is unique among moons of planetary mass in that its orbit is retrograde to Neptune's rotation and"
"Saturn Rhea is the second-largest moon of Saturn. Titan is the largest moon of Saturn. Its substantial atmosphere makes it the most Earth-like moon in the Solar System and hence a popular science fiction setting. Hyperion is the largest irregularly-shaped moon of Saturn, orbiting between Titan and Iapetus. Iapetus is a large moon orbiting further from Saturn than any of its other large satellites. Half of its surface is very bright while the other half is extremely dark. Investigations since 2004 have also noted its irregular shape, immense impact basins, and a high mountainous ridge on the equator. Phoebe is"
"10199 Chariklo 10199 Chariklo ( or ; ; provisional designation ) is the largest confirmed centaur (minor planet of the outer Solar System). It orbits the Sun between Saturn and Uranus, grazing the orbit of Uranus. On 26 March 2014, astronomers announced the discovery of two rings (nicknamed Oiapoque and Chuí) around Chariklo by observing a stellar occultation, making it the first minor planet known to have rings. Chariklo was discovered by James V. Scotti of the Spacewatch program on February 15, 1997. Chariklo is named after the nymph Chariclo (""""), the wife of Chiron and the daughter of Apollo."
"dynamical population of plutinos, named after its largest member, Pluto. Plutinos are resonant trans-Neptunian objects in a 2:3 orbital resonance with Neptune, which means that they orbit the Sun exactly twice while Neptune orbits the Sun three times. It orbits the Sun at a distance of 26.3–52.0 AU once every 244 years and 10 months (89,435 days; semi-major axis of 39.14 AU). Its orbit has a notably high eccentricity of 0.33 and an inclination of 6° with respect to the ecliptic. Among the plutinos, ' has one of the most elliptical orbits, with a perihelion almost halfway between Uranus (19.2"
"though the presence of ammonia on Titan would cause chemical reactions to proceed more slowly. Titan (moon) Titan is the largest moon of Saturn. It is the only moon known to have a dense atmosphere, and the only object in space, other than Earth, where clear evidence of stable bodies of surface liquid have been found. Titan is the sixth gravitationally rounded moon from Saturn. Frequently described as a planet-like moon, Titan is 50% larger than Earth's moon and 80% more massive. It is the second-largest moon in the Solar System after Jupiter's moon Ganymede, and is larger than the"
"Puck (moon) Puck ( ) is an inner moon of Uranus. It was discovered in December 1985 by the ""Voyager 2"" spacecraft. The name ""Puck"" follows the convention of naming Uranus's moons after characters from Shakespeare. The orbit of Puck lies between the rings of Uranus and the first of Uranus's large moons, Miranda. Puck is approximately spherical in shape and has diameter of about 162 km. It has a dark, heavily cratered surface, which shows spectral signs of water ice. Puck—the largest inner moon of Uranus—was discovered from the images taken by ""Voyager 2"" on 30 December 1985. It"
"Triton, called ""Triton Hopper"", would mine nitrogen ice from the surface of Triton and process it to be used as small rocket propellant and fly or 'hop' across the surface. On 5 October 2017 Triton occulted the star UCAC4 410-143659. Triton (moon) Triton is the largest natural satellite of the planet Neptune, and the first Neptunian moon to be discovered. The discovery was made on October 10, 1846, by English astronomer William Lassell. It is the only large moon in the Solar System with a retrograde orbit, an orbit in the direction opposite to its planet's rotation. At in diameter,"
"define the term ""planet"" formally in 2006, during their 26th General Assembly. That definition excluded Pluto and reclassified it as a dwarf planet. Pluto is the largest and second-most-massive known dwarf planet in the Solar System, and the ninth-largest and tenth-most-massive known object directly orbiting the Sun. It is the largest known trans-Neptunian object by volume but is less massive than Eris. Like other Kuiper belt objects, Pluto is primarily made of ice and rock and is relatively small—about one-sixth the mass of the Moon and one-third its volume. It has a moderately eccentric and inclined orbit during which it"
"that are more massive than Eris are the Moon, the four Galilean moons of Jupiter (Io, Europa, Ganymede, and Callisto), one moon of Saturn (Titan), and one moon of Neptune (Triton). The others are six moons of Saturn (Mimas, Enceladus, Tethys, Dione, Rhea, and Iapetus), five moons of Uranus (Miranda, Ariel, Umbriel, Titania, and Oberon), and one moon of Pluto (Charon). There are additional possibilities among TNOs, including Dysnomia orbiting Eris. Alan Stern calls these moons ""satellite planets"", one of three categories of planet together with dwarf planets and classical planets. The term ""planemo"" (""planetary-mass object"") covers all three. In"
"Kubrick Mons Kubrick Mons is the name given to the largest of a series of mountain peaks on Pluto's moon Charon that rise out of depressions in the ground in the Vulcan Planum plain. The feature was first recorded by the Long Range Reconnaissance Imager (LORRI) aboard the ""New Horizons"" spacecraft during a flyby on July 15, 2017. Kubrick Mons has a diameter between and is in height. The feature is surrounded by a moat which has a depth of below the surrounding area. , it is not known how Kubrick Mons formed, however there is speculation that Kubrick Mons"
"less than half that of Triton (the seventh-largest moon in the Solar System) alone. The largest of the satellites, Titania, has a radius of 788.9 km, or less than half that of the Moon, but slightly more than that of Rhea, the second-largest moon of Saturn, making Titania the eighth-largest moon in the Solar System. Uranus is about 10,000 times more massive than its moons. As of 2016, Uranus is known to have 13 inner moons. Their orbits lie inside that of Miranda. All inner moons are intimately connected to the rings of Uranus, which probably resulted from the fragmentation"
"letters. The name Pluto was officially adopted on May 1, 1930. Following the discovery, starting in the 1990s, of other Kuiper belt objects, Pluto began to be seen not as a planet orbiting alone at 40 AU, but as the largest of a group of icy bodies in that region of space. After it was shown that at least one such body was more massive than Pluto, on August 24, 2006 the International Astronomical Union (IAU) reclassified Pluto, grouping it with two similarly sized ""dwarf planets"" rather than with the eight ""classical planets"". Tombaugh's widow Patricia stated after the IAU's"
"In the original draft proposal, an exception was made for Pluto and its largest satellite, Charon, which possess a barycenter outside the volume of either body. The initial proposal classified Pluto–Charon as a double planet, with the two objects orbiting the Sun in tandem. However, the final draft made clear that, even though they are similar in relative size, only Pluto would currently be classified as a dwarf planet. However, some have suggested that the Moon nonetheless deserves to be called a planet. In 1975, Isaac Asimov noted that the timing of the Moon's orbit is in tandem with the"
"moons orbit Pluto at two to four times the distance of Charon, ranging from Styx at 42,700 kilometres to Hydra at 64,800 kilometres from the barycenter of the system. They have nearly circular prograde orbits in the same orbital plane as Charon. All are much smaller than Charon. Nix and Hydra, the two larger, are roughly 42 and 55 kilometers on their longest axis respectively, and Styx and Kerberos are 7 and 12 kilometers respectively. All four are irregularly shaped. The Pluto system is highly compact and largely empty. Moons could potentially orbit Pluto at up to 53% (or 69%,"
"Kerberos (moon) Kerberos is a small natural satellite of Pluto, about in its longest dimension. It was the fourth moon of Pluto to be discovered and its existence was announced on 20 July 2011. It was imaged, along with Pluto and its four other moons, by the ""New Horizons"" spacecraft in July 2015. The first image of Kerberos was released to the public on 22 October 2015. Kerberos was discovered by the Pluto Companion Search Team using the Hubble Space Telescope on 28 June 2011, using the Wide Field Camera 3, during an attempt to find any rings that Pluto"
"reflective. This meant that Pluto, far from being dark, was in fact exceptionally bright, and thus was probably no more than Earth mass. Pluto's size was finally determined conclusively in 1978, when American astronomer James W. Christy discovered its moon Charon. This enabled him, together with Robert Sutton Harrington of the U.S. Naval Observatory, to measure the mass of the Pluto–Charon system directly by observing the moon's orbital motion around Pluto. They determined Pluto's mass to be 1.31×10 kg; roughly one five-hundredth that of Earth or one-sixth that of the Moon, and far too small to account for the observed"
"Tombaugh Regio Tombaugh Regio (), nicknamed The Heart after its shape, is the largest bright surface feature of the dwarf planet Pluto. It is just north of the equator, to the northeast of Cthulhu Macula and to the northwest of Krun Macula, which are both dark features. Its western lobe, a 1000 km-wide plain of nitrogen and other ices, is named Sputnik Planitia. The eastern lobe consists of high-albedo uplands thought to be coated by nitrogen transported through the atmosphere from Sputnik Planitia, and then deposited as ice. Some of this nitrogen ice then returns to Sputnik Planitia via glacial"
"Proteus (moon) Proteus ( ; Greek: ""Πρωτεύς""), also known as Neptune VIII, is the second-largest Neptunian moon, and Neptune's largest inner satellite. Discovered by ""Voyager 2"" spacecraft in 1989, it is named after Proteus, the shape-changing sea god of Greek mythology. Proteus orbits Neptune in a nearly equatorial orbit at the distance of about 4.75 equatorial radii of the planet. Despite being a predominantly icy body more than 400 km in diameter, Proteus's shape deviates significantly from an ellipsoid. It is shaped more like an irregular polyhedron with several slightly concave facets and relief as high as 20 km. Its"
"the expansion continued, but some of the angular moment was transferred to Europa as the resonance caused its orbit to expand as well; the process continued until Europa encountered the 2:1 resonance with Ganymede. Eventually the drift rates of conjunctions between all three moons were synchronized and locked in the Laplace resonance. Ganymede is the largest and most massive moon in the Solar System. Its diameter of 5,268 km is 0.41 times that of Earth, 0.77 times that of Mars, 1.02 times that of Saturn's Titan (the second-largest moon), 1.08 times Mercury's, 1.09 times Callisto's, 1.45 times Io's and 1.51"
"the Kuiper belt, together with the members of the scattered disc and any potential Hills cloud or Oort cloud objects, are collectively referred to as trans-Neptunian objects (TNOs). Pluto is the largest and most massive member of the Kuiper belt, and the largest and the second-most-massive known TNO, surpassed only by Eris in the scattered disc. Originally considered a planet, Pluto's status as part of the Kuiper belt caused it to be reclassified as a dwarf planet in 2006. It is compositionally similar to many other objects of the Kuiper belt and its orbital period is characteristic of a class"
"moon Triton to be investigated around 2029. The proposed ""New Horizons 2"" mission (which was later scrapped) might also have done a close flyby of the Neptunian system. Neptune Neptune is the eighth and farthest known planet from the Sun in the Solar System. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune. Neptune orbits the Sun once every 164.8"