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Saturnian System
The moons of Saturn are numerous and diverse, ranging from tiny moonlets only tens of meters across to enormous Titan, which is larger than the planet Mercury. Saturn has 83 moons with confirmed orbits that are not embedded in its rings—of which only 13 have diameters greater than 50 kilometers—as well as dense rings that contain millions of embedded moonlets and innumerable smaller ring particles. 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. Particularly notable among Saturn's moons are Titan, the second-largest moon in the Solar System (after Jupiter's Ganymede), with a nitrogen-rich Earth-like atmosphere and a landscape featuring dry river networks and hydrocarbon lakes, Enceladus, which emits jets of gas and dust from its south-polar region, and Iapetus, with its contrasting black and white hemispheres. Twenty-four of Satu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, but in that year, 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, Cassini–Huygens , Cassini caught an object 4–5 kilometers 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 small moons have been called moonlets: * A belt of objects embedded in a planetary ring, especially around Saturn, such as those in the Rings of Saturn#A Ring, A Ring, S/2009 S 1 in the B Ring (Moons of Saturn#Ring moonlets, "propeller" moonlets), and those in the Rings of Saturn#F Ring, F Ring * Occasionally asteroid moons, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the Equator, the plane of the satellite's orbit is the same as the Earth's equatorial plane, and the satellite's orbital inclination is 0°. The general case for a circular orbit is that it is tilted, spending half an orbit over the northern hemisphere and half over the southern. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°. Orbits The inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the orbital plane and the plane of reference, normally stated in degree (angle), degrees. For a satellite orbiting a planet, the plane of reference is usually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retrograde Motion
Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is, the central object (right figure). It may also describe other motions such as precession or nutation of an object's rotational axis. Prograde or direct motion is more normal motion in the same direction as the primary rotates. However, "retrograde" and "prograde" can also refer to an object other than the primary if so described. The direction of rotation is determined by an inertial frame of reference, such as distant fixed stars. In the Solar System, the orbits around the Sun of all planets and most other objects, except many comets, are prograde. They orbit around the Sun in the same direction as the sun rotates about its axis, which is counterclockwise when observed from above the Sun's north pole. Except for Venus and Uranus, planetary rotations around their axes are also prograde. Most natural satellites have prograde or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the Equator, the plane of the satellite's orbit is the same as the Earth's equatorial plane, and the satellite's orbital inclination is 0°. The general case for a circular orbit is that it is tilted, spending half an orbit over the northern hemisphere and half over the southern. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°. Orbits The inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the orbital plane and the plane of reference, normally stated in degrees. For a satellite orbiting a planet, the plane of reference is usually the plane containing the planet's equator. For pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Irregular moons have a stable orbit, unlike temporary satellites which often have similarly irregular orbits but will eventually depart. The term does not refer to shape as Triton is a round moon, but is considered irregular due to its orbit. As of December 2022, 149 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 locations, shortly after the formation of their parent planet. An alternative theory, that they originated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saturn (mythology)
Saturn ( la, Sāturnus ) was a god in ancient Roman religion, and a character in Roman mythology. He was described as a god of time, generation, dissolution, abundance, wealth, agriculture, periodic renewal and liberation. Saturn's mythological reign was depicted as a Golden Age of abundance and peace. After the Roman conquest of Greece, he was conflated with the Greek Titan Cronus. Saturn's consort was his sister Ops, with whom he fathered Jupiter, Neptune, Pluto, Juno, Ceres and Vesta. Saturn was especially celebrated during the festival of Saturnalia each December, perhaps the most famous of the Roman festivals, a time of feasting, role reversals, free speech, gift-giving and revelry. The Temple of Saturn in the Forum Romanum, Roman Forum housed the state treasury and archives (''aerarium'') of the Roman Republic and the early Roman Empire. The planet Saturn and the day of the week Saturday are both named after and were associated with him. Mythology The Roman land preserv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titan (mythology)
In Greek mythology, the Titans ( grc, οἱ Τῑτᾶνες, ''hoi Tītânes'', , ''ho Tītân'') were the pre-Olympian gods. According to the ''Theogony'' of Hesiod, they were the twelve children of the primordial parents Uranus (Sky) and Gaia (Earth), with six male Titans— Oceanus, Coeus, Crius, Hyperion, Iapetus, and Cronus—and six female Titans, called the Titanides or "Titanesses" (, ''hai Tītānídes'')—Theia, Rhea, Themis, Mnemosyne, Phoebe, and Tethys. Cronus mated with his older sister Rhea, who then bore the first generation of Olympians: the six siblings Zeus, Hades, Poseidon, Hestia, Demeter, and Hera. Certain descendants of the Titans, such as Prometheus, Helios, and Leto, are sometimes also called Titans. The Titans were the former gods: the generation of gods preceding the Olympians. They were overthrown as part of the Greek succession myth, which tells how Cronus seized power from his father Uranus and ruled the cosmos with his fellow Titans b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mimas (moon)
Mimas , also designated Saturn I, is a moon of Saturn discovered in 1789 by William Herschel. It is named after Mimas, a son of Gaia in Greek mythology. With a diameter of , it is the smallest astronomical body that is known to still be rounded in shape because of self-gravitation. However, Mimas is not actually in hydrostatic equilibrium for its current rotation. Discovery Mimas was discovered by the astronomer William Herschel on 17 September 1789. He recorded his discovery as follows: "I continued my observations constantly, whenever the weather would permit; and the great light of the forty-feet speculum was now of so much use, that I also, on the 17th of September, detected the seventh satellite, when it was at its greatest preceding elongation." The 40-foot telescope was a metal mirror reflecting telescope built by Herschel, with a aperture. The 40 feet refers to the length of the focus, not the aperture diameter as more common with modern telescopes. Name Mima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A Ring
The rings of Saturn are the most extensive 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 Rock (geology), 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–Huygens, Cassini'' suggested they formed relatively late. Although reflection from the rings increases Saturn's apparent magnitude, brightness, they are not visible from Earth with naked eye, unaided vision. In 1610, the year after Galileo Galilei turned a telescope to the sky, he became the first person to observe Saturn's rings, though he could not see them well enough to discern their true nature. In 1655, Christiaan Huygens was the first person to describe t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Resonance
In celestial mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly, this relationship is found between a pair of objects (binary resonance). The physical principle behind orbital resonance is similar in concept to pushing a child on a swing, whereby the orbit and the swing both have a natural frequency, and the body doing the "pushing" will act in periodic repetition to have a cumulative effect on the motion. Orbital resonances greatly enhance the mutual gravitational influence of the bodies (i.e., their ability to alter or constrain each other's orbits). In most cases, this results in an ''unstable'' interaction, in which the bodies exchange momentum and shift orbits until the resonance no longer exists. Under some circumstances, a resonant system can be self-correcting and thus stable. Examples are the 1:2:4 resonance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperion (moon)
Hyperion , also known as Saturn VII, is a moon of Saturn discovered by William Cranch Bond, his son George Phillips Bond and William Lassell in 1848. It is distinguished by its irregular shape, its chaotic rotation, and its unexplained sponge-like appearance. It was the first non-round moon to be discovered. Name The moon is named after Hyperion, the Titan god of watchfulness and observation – the elder brother of Cronus, the Greek equivalent of the Roman god Saturn. It is also designated ''Saturn VII''. The adjectival form of the name is ''Hyperionian''. Hyperion's discovery came shortly after John Herschel had suggested names for the seven previously known satellites of Saturn in his 1847 publication ''Results of Astronomical Observations made at the Cape of Good Hope''. William Lassell, who saw Hyperion two days after William Bond, had already endorsed Herschel's naming scheme and suggested the name Hyperion in accordance with it. He also beat Bond to pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
F Ring
The rings of Saturn are the most extensive 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. Although reflection from the rings increases Saturn's brightness, they are not visible from Earth with unaided vision. In 1610, the year after Galileo Galilei turned a telescope to the sky, he became the first person to observe Saturn's rings, though he could not see them well enough to discern their true nature. In 1655, Christiaan Huygens was the first person to describe them as a disk surrounding Saturn. The concept that Saturn's rin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
