"enough to establish orbits. Planets around other stars are likely to have satellites as well, and although numerous candidates have been detected to date, none have yet been confirmed. Of the inner planets, Mercury and Venus have no natural satellites; Earth has one large natural satellite, known as the Moon; and Mars has two tiny natural satellites, Phobos and Deimos. The giant planets have extensive systems of natural satellites, including half a dozen comparable in size to Earth's Moon: the four Galilean moons, Saturn's Titan, and Neptune's Triton. Saturn has an additional six mid-sized natural satellites massive enough to have"
"Earth's natural satellite is simply known as the Moon, or the equivalent in the language being spoken (for instance, two astronomers speaking French would call it ""la Lune""). It is sometimes called ""Luna"" (which is simply Latin for ""moon""), in science fiction. Natural satellites of other planets are generally named after mythological figures. Satellites of Uranus are named after characters from works by William Shakespeare or Alexander Pope. When natural satellites are first discovered, they are given provisional designations such as ""S/2010 J 2"" (the 2nd new satellite of Jupiter discovered in 2010) or ""S/2003 S 1"" (the 1st new"
"body, though this is somewhat arbitrary, because it depends on distance as well as relative mass. The natural satellites orbiting relatively close to the planet on prograde, uninclined circular orbits (""regular"" satellites) are generally thought to have been formed out of the same collapsing region of the protoplanetary disk that created its primary. In contrast, irregular satellites (generally orbiting on distant, inclined, eccentric and/or retrograde orbits) are thought to be captured asteroids possibly further fragmented by collisions. Most of the major natural satellites of the Solar System have regular orbits, while most of the small natural satellites have irregular orbits."
"Inner moon In astronomy, an inner moon or inner natural satellite is a natural satellite following a prograde, low-inclination orbit inwards of the large satellites of the parent planet. They are generally thought to have been formed ""in situ"" at the same time as the coalescence of the original planet. Neptune's moons are an exception, as they are likely reaggregates of the pieces of the original bodies, which were disrupted after the capture of the large moon Triton. Inner satellites are distinguished from other regular satellites by their proximity to the parent planet, their short orbital periods (usually under a"
"the smallest natural satellites. Known satellite systems of the Solar System consisting of multiple objects or around planetary mass objects, in order of perihelion: Natural satellite systems, particularly those involving multiple planetary mass objects can have complex interactions which can have effects on multiple bodies or across the wider system. Ring systems are collections of dust, moonlets, or other small objects. The most notable examples are those around Saturn, but the other three gas giants (Jupiter, Uranus and Neptune) also have ring systems. Studies of exoplanets indicate that they may be common around giant planets. The 90 million km (0.6"
"Subsatellite A subsatellite is a natural satellite (or an artificial satellite) that orbits a natural satellite, i.e. a ""moon of a moon"", also known as a moonmoon, submoon, or grandmoon. It is inferred from the empirical study of natural satellites in the Solar System that subsatellites may be elements of planetary systems. In the Solar System, the giant planets have large collections of natural satellites. The majority of detected exoplanets are giant planets; at least one, Kepler-1625b, may have a very large exomoon, named Kepler-1625b I. Therefore, it is reasonable to assume that subsatellites may exist in the Solar System,"
"natural satellites (moons) differ from small Solar System bodies not in size, but in their orbits. The orbits of natural satellites are not centered on the Sun, but around other Solar System objects such as planets, dwarf planets, and small Solar System bodies. Some of the larger small Solar System bodies may be reclassified in future as dwarf planets, pending further examination to determine whether or not they are in hydrostatic equilibrium. The orbits of the vast majority of small Solar System bodies are located in two distinct areas, namely the asteroid belt and the Kuiper belt. These two belts"
"Irregular moon In astronomy, an irregular moon, irregular satellite or irregular natural satellite is a natural satellite following a distant, inclined, and often eccentric and retrograde orbit. They have been captured by their parent planet, unlike regular satellites, which formed in orbit around them. As of July 2018, 125 irregular moons are known, orbiting all four of the outer planets (Jupiter, Saturn, Uranus and Neptune). The largest of each planet are Himalia of Jupiter, Phoebe of Saturn, Sycorax of Uranus, and Triton of Neptune. It is currently thought that the irregular satellites were captured from heliocentric orbits near their current"
"Statite A statite (a portmanteau of ""static"" and ""satellite"") is a hypothetical type of artificial satellite that employs a solar sail to continuously modify its orbit in ways that gravity alone would not allow. Typically, a statite would use the solar sail to ""hover"" in a location that would not otherwise be available as a stable geosynchronous orbit. Statites have been proposed that would remain in fixed locations high over Earth's poles, using reflected sunlight to counteract the gravity pulling them down. Statites might also employ their sails to change the shape or velocity of more conventional orbits, depending upon"
"Lagrange point near the Earth/Sun L1 point, to demonstrate the feasibility of the Geostorm geomagnetic storm warning mission concept proposed by NOAA's Patricia Mulligan. Statite A statite (a portmanteau of ""static"" and ""satellite"") is a hypothetical type of artificial satellite that employs a solar sail to continuously modify its orbit in ways that gravity alone would not allow. Typically, a statite would use the solar sail to ""hover"" in a location that would not otherwise be available as a stable geosynchronous orbit. Statites have been proposed that would remain in fixed locations high over Earth's poles, using reflected sunlight to"
"Satellite system (astronomy) A satellite system is a set of gravitationally bound objects in orbit around a planetary mass object or minor planet. Generally speaking, it is a set of natural satellites (moons), although such systems may also consist of bodies such as circumplanetary disks, ring systems, moonlets, minor-planet moons and artificial satellites any of which may themselves have satellite systems of their own. Some bodies also possess quasi-satellites that have orbits gravitationally influenced by their primary, but are generally not considered to be part of a satellite system. Satellite systems can have complex interactions including magnetic, tidal, atmospheric and"
"Habitability of natural satellites The habitability of natural satellites is a measure of the potential of natural satellites to have environments hospitable to life. Habitable environments do not necessarily harbor life. Planetary habitability is an emerging study which is considered important to astrobiology for several reasons, foremost being that natural satellites are predicted to greatly outnumber planets and that it is hypothesized that habitability factors are likely to be similar to those of planets. There are, however, key environmental differences which have a bearing on moons as potential sites for extraterrestrial life. The strongest candidates for natural satellite habitability are"
"and Haumea's two were formed in orbit about those dwarf planets out of debris created in giant collisions. Regular moon In astronomy, a regular moon is a natural satellite following a relatively close and prograde orbit with little orbital inclination or eccentricity. They are believed to have formed in orbit about their primary, as opposed to irregular moons, which were captured. There are at least 57 regular satellites of the eight planets: one at Earth, eight at Jupiter, 23 named regular moons at Saturn (not counting hundreds or thousands of moonlets), 18 known at Uranus, and 7 small regular moons"
"inner satellites have been imaged by the spacecraft ""Voyager 1"" and ""Voyager 2"". The majority have only been seen in images as single pixels, or resolved to only a few pixels across. However fairly detailed surface features have been seen on the following moons: Inner moon In astronomy, an inner moon or inner natural satellite is a natural satellite following a prograde, low-inclination orbit inwards of the large satellites of the parent planet. They are generally thought to have been formed ""in situ"" at the same time as the coalescence of the original planet. Neptune's moons are an exception, as"
"reports of natural satellite discoveries used the term ""satellite"" exclusively, though the 1868 book ""Smith's Illustrated Astronomy"" referred to satellites as ""secondary planets"". One of the unexpected results of William Herschel's discovery of Uranus was that it appeared to validate Bode's law, a mathematical function which generates the size of the semimajor axis of planetary orbits. Astronomers had considered the ""law"" a meaningless coincidence, but Uranus fell at very nearly the exact distance it predicted. Since Bode's law also predicted a body between Mars and Jupiter that at that point had not been observed, astronomers turned their attention to that"
"Moonlet A moonlet, minor moon, minor natural satellite, or minor satellite is a particularly small natural satellite orbiting a planet, dwarf planet, or other minor planet. Up until 1995, moonlets were only hypothetical components of Saturn's F-ring structure, when the Earth passed through Saturn's ring plane. The Hubble Space Telescope and the European Southern Observatory both captured objects orbiting close or near the F-ring. In 2004, when Cassini caught an object 4-5km in diameter on the outer ring of the F-ring and then 5 hours later on the inner F-ring, showing that the object had orbited. Three different types of"
"Moon The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite. It is the fifth-largest natural satellite in the Solar System, and the largest among planetary satellites relative to the size of the planet that it orbits (its primary). The Moon is after Jupiter's satellite Io the second-densest satellite in the Solar System among those whose densities are known. The Moon is thought to have formed about 4.51 billion years ago, not long after Earth. The most widely accepted explanation is that the Moon formed from the debris left over after a giant"
"Solar System bodies. Some studies estimate that up to 15% of all trans-Neptunian objects could have satellites. The following is a comparative table classifying the natural satellites in the Solar System by diameter. The column on the right includes some notable planets, dwarf planets, asteroids, and trans-Neptunian objects for comparison. The natural satellites of the planets are named after mythological figures. These are predominantly Greek, except for the Uranian natural satellites, which are named after Shakespearean characters. The nineteen bodies massive enough to have achieved hydrostatic equilibrium are in bold in the table below. Minor planets and satellites suspected but"
"its regular cycle of phases as seen from Earth have provided cultural references and influences for human societies and cultures since time immemorial. Such cultural influences can be found in language, lunar calendar systems, art, and mythology. The usual English proper name for Earth's natural satellite is ""the Moon"", which in nonscientific texts is usually not capitalized. The noun ""moon"" is derived from Old English ""mōna"", which (like all Germanic language cognates) stems from Proto-Germanic ""*mēnô"", which comes from Proto-Indo-European ""*mḗh₁n̥s"" ""moon"", ""month"", which comes from the Proto-Indo-European root ""*meh₁-"" ""to measure"", the month being the ancient unit of time"
"Amateur radio satellite An amateur radio satellite is an artificial satellite built and used by amateur radio operators for use in the Amateur-satellite service. These satellites use amateur radio frequency allocations to facilitate communication between amateur radio stations. Many amateur-satellites receive an OSCAR designation, which is an acronym for Orbiting Satellite Carrying Amateur Radio. The designation is assigned by AMSAT, an organization which promotes the development and launch of amateur radio satellites. Because of the prevalence of this designation, amateur radio satellites are often referred to as OSCARs. These satellites can be used for free by licensed amateur radio operators"
"small moons have been called moonlets: Moonlet A moonlet, minor moon, minor natural satellite, or minor satellite is a particularly small natural satellite orbiting a planet, dwarf planet, or other minor planet. Up until 1995, moonlets were only hypothetical components of Saturn's F-ring structure, when the Earth passed through Saturn's ring plane. The Hubble Space Telescope and the European Southern Observatory both captured objects orbiting close or near the F-ring. In 2004, when Cassini caught an object 4-5km in diameter on the outer ring of the F-ring and then 5 hours later on the inner F-ring, showing that the object"
"traffic accidents, homicides or suicides increase during a full moon, but dozens of studies invalidate these claims. Moon The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite. It is the fifth-largest natural satellite in the Solar System, and the largest among planetary satellites relative to the size of the planet that it orbits (its primary). The Moon is after Jupiter's satellite Io the second-densest satellite in the Solar System among those whose densities are known. The Moon is thought to have formed about 4.51 billion years ago, not long after Earth. The"
"Satellite state A satellite state is a country that is formally independent in the world, but under heavy political, economic and military influence or control from another country. The term was coined by analogy to planetary objects orbiting a larger object, such as smaller moons revolving around larger planets, and is used mainly to refer to Central and Eastern European countries of the Warsaw Pact during the Cold War or to Mongolia or Tannu Tuva between 1924 and 1990, for example. As used for Central and Eastern European countries it implies that the countries in question were ""satellites"" under the"
"locations, shortly after the formation of their parent planet. An alternative theory, that they originated further out in the Kuiper belt, is not supported by current observations. There is no widely accepted precise definition of an irregular satellite. Informally, satellites are considered irregular if they are far enough from the planet that the precession of their orbital plane is primarily controlled by the Sun. In practice, the satellite's semi-major axis is compared with the radius of the planet's Hill sphere (that is, the sphere of its gravitational influence), formula_1. Irregular satellites have semi-major axes greater than 0.05 formula_1 with apoapses"
"Rhea. It has also been proposed that Saturn's satellite Iapetus possessed a subsatellite in the past; this is one of several hypotheses that have been put forward to account for its unusual equatorial ridge. Many spacecraft have orbited the Moon, including manned craft of the Apollo program. , none have orbited any other moons. In 1988 the Soviet Union unsuccessfully attempted to put two unmanned probes on quasi-orbits around the Martian moon Phobos. Subsatellite A subsatellite is a natural satellite (or an artificial satellite) that orbits a natural satellite, i.e. a ""moon of a moon"", also known as a moonmoon,"
"Sponde Sponde ( ; Greek: ""Σπονδή""), also known as ', is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2001, and given the temporary designation '. Sponde is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 24,253 Mm in 771.604 days, at an inclination of 154° to the ecliptic (156° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.443. It was named in August 2003 after one of the Horae (Hours), which presided over the"
"and civilian Earth observation satellites, communications satellites, navigation satellites, weather satellites, and space telescopes. Space stations and human spacecraft in orbit are also satellites. Satellite orbits vary greatly, depending on the purpose of the satellite, and are classified in a number of ways. Well-known (overlapping) classes include low Earth orbit, polar orbit, and geostationary orbit. A launch vehicle is a rocket that places a satellite into orbit. Usually, it lifts off from a launch pad on land. Some are launched at sea from a submarine or a mobile maritime platform, or aboard a plane (see air launch to orbit). Satellites"
"Regular moon In astronomy, a regular moon is a natural satellite following a relatively close and prograde orbit with little orbital inclination or eccentricity. They are believed to have formed in orbit about their primary, as opposed to irregular moons, which were captured. There are at least 57 regular satellites of the eight planets: one at Earth, eight at Jupiter, 23 named regular moons at Saturn (not counting hundreds or thousands of moonlets), 18 known at Uranus, and 7 small regular moons at Neptune (Neptune's largest moon Triton appears to have been captured). It is thought that Pluto's five moons"
"1964 Summer Olympics in Tokyo to the United States. Westar 1 was America's first domestic and commercially launched geostationary communications satellite, launched by Western Union and NASA on April 13, 1974. Geosynchronous satellite A geosynchronous satellite is a satellite in geosynchronous orbit, with an orbital period the same as the Earth's rotation period. Such a satellite returns to the same position in the sky after each sidereal day, and over the course of a day traces out a path in the sky that is typically some form of analemma. A special case of geosynchronous satellite is the geostationary satellite, which"
"the smaller mass with regard to its orbit around the larger mass. The triangular points ( and ) are stable equilibria, provided that the ratio of M/M is greater than 24.96. When a body at these points is perturbed, it moves away from the point, but the factor opposite of that which is increased or decreased by the perturbation (either gravity or angular momentum-induced speed) will also increase or decrease, bending the object's path into a stable, kidney-bean-shaped orbit around the point (as seen in the corotating frame of reference). It is generally thought that natural satellites should orbit in"
"years 2015–2019 with a market value estimated at . By mid-2015, many more launch options had become available for smallsats, and rides as secondary payloads had become both greater in quantity and with the ability to schedule on shorter notice. The term ""small satellite"", or sometimes ""minisatellite"", often refers to an artificial satellite with a wet mass (including fuel) between , but in other usage has come to mean any satellite under . Small satellite examples include Demeter, Essaim, Parasol, Picard, MICROSCOPE, TARANIS, ELISA, SSOT, SMART-1, and Spirale-A and -B. Although smallsats have traditionally been launched as secondary payloads on"
"Exomoon An exomoon or extrasolar moon is a natural satellite that orbits an exoplanet or other non-stellar extrasolar body. It is inferred from the empirical study of natural satellites in the Solar System that they are likely to be common elements of planetary systems. The majority of detected exoplanets are giant planets. In the Solar System, the giant planets have large collections of natural satellites (see Moons of Jupiter, Moons of Saturn, Moons of Uranus and Moons of Neptune). Therefore, it is reasonable to assume that exomoons are equally common. Though exomoons are difficult to detect and confirm using current"
"achieved hydrostatic equilibrium, and Uranus has five. It has been suggested that some satellites may potentially harbour life. Among the identified dwarf planets, Ceres has no known natural satellites. Pluto has the relatively large natural satellite Charon and four smaller natural satellites; Styx, Nix, Kerberos, and Hydra. Haumea has two natural satellites, and Eris and Makemake have one each. The Pluto–Charon system is unusual in that the center of mass lies in open space between the two, a characteristic sometimes associated with a double-planet system. The seven largest natural satellites in the Solar System (those bigger than 2,500 km across)"