Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine-and-a-half times that of Earth. It has only one-eighth the average density of Earth, but is over 95 times more massive. However, even though Saturn is nearly the size of Jupiter, Saturn has less than one-third of Jupiter's mass.
A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body. Natural satellites are colloquially referred to as moons, a derivation from the Moon of Earth.
Rhea is the second-largest moon of Saturn and the ninth-largest moon in the Solar System, with a surface area that is comparable to the area of Australia. It is the smallest body in the Solar System for which precise measurements have confirmed a shape consistent with hydrostatic equilibrium. It was discovered in 1672 by Giovanni Domenico Cassini.
Tethys, or Saturn III, is a mid-sized moon of Saturn about 1,060 km (660 mi) across. It was discovered by G. D. Cassini in 1684 and is named after the titan Tethys of Greek mythology.
Iapetus is a moon of Saturn. With an estimated diameter of 1,469 km, it is the third-largest moon of Saturn and the eleventh-largest in the Solar System. Named after the Titan Iapetus, the moon was discovered in 1671 by Giovanni Domenico Cassini.
Janus is an inner satellite of Saturn. It is also known as Saturn X. It is named after the mythological Janus.
Epimetheus is an inner satellite of Saturn. It is also known as Saturn XI. It is named after the mythological Epimetheus, brother of Prometheus.
Hyperion, also known as Saturn VII, is a moon of Saturn distinguished by its highly irregular shape, chaotic rotation, extremely low density and its unexplained sponge-like appearance. It was the first non-round moon to be discovered.
Mimas, also designated Saturn I, is a natural satellite of Saturn that has the second largest crater on any moon in the Solar System, named Herschel. The Herschel crater measures 139 kilometres across, about one-third of Mimas's mean diameter, and is believed to be formed from an extremely energetic impact event. The crater's name is derived from the discoverer of Mimas, William Herschel, in 1789.
Phoebe is the most massive irregular satellite of Saturn with a mean diameter of 213 km (132 mi). It was discovered by William Henry Pickering on 18 March 1899 from photographic plates that had been taken starting on 16 August 1898 at the Boyden Station of the Carmen Alto Observatory near Arequipa, Peru, by DeLisle Stewart. It was the first satellite to be discovered photographically.
Prometheus is an inner satellite of Saturn. It was discovered in 1980 from photos taken by the Voyager 1 probe, and was provisionally designated S/1980 S 27.
This article provides a timeline of the Cassini–Huygens mission. Cassini was a collaboration between the United States' NASA, the European Space Agency ("ESA"), and the Italian Space Agency ("ASI") to send a probe to study the Saturnian system, including the planet, its rings, and its natural satellites. The Flagship-class uncrewed robotic spacecraft comprised both NASA's Cassini probe, and ESA's Huygens lander which was designed to land on Saturn's largest moon, Titan. Cassini was the fourth space probe to visit Saturn and the first to enter its orbit. The craft were named after astronomers Giovanni Cassini and Christiaan Huygens.
The moons of Saturn are numerous and diverse, ranging from tiny moonlets only tens of meters across to the enormous Titan, which is larger than the planet Mercury. There are 146 moons with confirmed orbits, the most of any planet in the solar system. This number does not include the many thousands of moonlets embedded within Saturn's dense rings, nor hundreds of possible kilometer-sized distant moons that were seen through telescopes but not recaptured. Seven Saturnian moons are large enough to have collapsed into a relaxed, ellipsoidal shape, though only one or two of those, Titan and possibly Rhea, are currently in hydrostatic equilibrium. Three moons are particularly notable. Titan is the second-largest moon in the Solar System, with a nitrogen-rich Earth-like atmosphere and a landscape featuring river networks and hydrocarbon lakes. Enceladus emits jets of ice from its south-polar region and is covered in a deep layer of snow. Iapetus has contrasting black and white hemispheres as well as an extensive ridge of equatorial mountains among the tallest in the solar system.
Skathi, also named Saturn XXVII and originally spelled Skadi, is a natural satellite of the planet Saturn. Skathi is one of Saturn's irregular moons, in its Norse group of satellites. It was discovered on September 23, 2000, by a team of astronomers led by Brett Gladman. The team announced their discovery on December 7, 2000, along with seven other satellites of Saturn, namely; Tarvos, Ijiraq, Thrymr, Siarnaq, Mundilfari, Erriapus, and Suttungr. The moon was named after Skaði, a figure in Norse mythology, as part of an effort to diversify the largely Greek and Roman names of astronomical objects.
William Henry Pickering was an American astronomer. Pickering constructed and established several observatories or astronomical observation stations, notably including Percival Lowell's Flagstaff Observatory. He led solar eclipse expeditions and studied craters on the Moon, and hypothesized that changes in the appearance of the crater Eratosthenes were due to "lunar insects". He spent much of the later part of his life at his private observatory in Jamaica.
The rings of Saturn are the most extensive and complex ring system of any planet in the Solar System. They consist of countless small particles, ranging in size from micrometers to meters, that orbit around Saturn. The ring particles are made almost entirely of water ice, with a trace component of rocky material. There is still no consensus as to their mechanism of formation. Although theoretical models indicated that the rings were likely to have formed early in the Solar System's history, newer data from Cassini suggested they formed relatively late.
Chiron is the name given to a supposed moon of Saturn sighted by Hermann Goldschmidt in 1861. It has since been determined that no such moon exists.
A planetary-mass moon is a planetary-mass object that is also a natural satellite. They are large and ellipsoidal in shape. Moons may be in hydrostatic equilibrium due to tidal or radiogenic heating, in some cases forming a subsurface ocean. Two moons in the Solar System are larger than the planet Mercury : Ganymede and Titan, and seven are larger and more massive than the dwarf planets Pluto and Eris.
Solar eclipses on Saturn occur when the natural satellites of Saturn pass in front of the Sun as seen from Saturn. These eclipses happen fairly often. For example, some of Saturn's moons can have a solar eclipse every day depending on the saturnian season.
2013 VZ70 is a centaur on a horseshoe co-orbital configuration with Saturn. It was first observed on 1 November 2013 by the Outer Solar System Origins Survey at Mauna Kea Observatory in Hawaii, United States. The discovery was announced on 23 August 2021.
