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Polydeuces (moon)
Polydeuces , or Saturn XXXIV, is a small natural satellite of Saturn that is co-orbital with the moon Dione and librates around its trailing Lagrangian point (). Its diameter is estimated to be 2–3 km. Dione's other co-orbital moon is Helene, which is bigger and located at the leading L4 point. Polydeuces was discovered by thCassini Imaging Team on October 24, 2004, in images taken on October 21, 2004, and given the temporary designation S/2004 S 5. Subsequent searches of earlier ''Cassini'' imaging showed it in images as far back as April 9, 2004. Of the four known Lagrangian co-orbitals in the Saturn system ('trojan moon'), Polydeuces wanders the farthest from its Lagrangian point: its distance behind Dione varies from 33.9° to 91.4° with a period of 790.931 days (for comparison, trails Dione by 60°). Polydeuces's libration is large enough that it takes on some qualities of a tadpole orbit, as evidenced by the clear asymmetry between excursion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lexico
Lexico was a dictionary website that provided a collection of English and Spanish dictionaries produced by Oxford University Press (OUP), the publishing house of the University of Oxford. While the dictionary content on Lexico came from OUP, this website was operated by Dictionary.com, whose eponymous website hosts dictionaries by other publishers such as Random House. The website was closed and redirected to Dictionary.com on 26 August 2022. Before the Lexico site was launched, the '' Oxford Dictionary of English'' and ''New Oxford American Dictionary'' were hosted by OUP's own website Oxford Dictionaries Online (ODO), later known as Oxford Living Dictionaries. The dictionaries' definitions have also appeared in Google definition search and the Dictionary application on macOS, among others, licensed through the Oxford Dictionaries API. History In the 2000s, OUP allowed access to content of the ''Compact Oxford English Dictionary of Current English'' on a website called AskOx ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Libration
In lunar astronomy, libration is the wagging or wavering of the Moon perceived by Earth-bound observers and caused by changes in their perspective. It permits an observer to see slightly different hemispheres of the surface at different times. It is similar in both cause and effect to the changes in the Moon's apparent size due to changes in distance. It is caused by three mechanisms detailed below, two of which cause a relatively tiny physical libration via tidal forces exerted by the Earth. Such true librations are known as well for other moons with locked rotation. The quite different phenomenon of a trojan asteroid's movement has been called ''Trojan libration''; and ''Trojan libration point'' means Lagrangian point. Lunar libration The Moon keeps one hemisphere of itself facing the Earth, due to tidal locking. Therefore, the first view of the far side of the Moon was not possible until the Soviet probe Luna 3 reached the Moon on October 7, 1959, and further lunar exp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trojan Moons
In astronomy, a co-orbital configuration is a configuration of two or more astronomical objects (such as asteroids, moons, or planets) orbiting at the same, or very similar, distance from their primary, i.e. they are in a 1:1 mean-motion resonance. (or 1:−1 if orbiting in opposite directions). There are several classes of co-orbital objects, depending on their point of libration. The most common and best-known class is the trojan, which librates around one of the two stable Lagrangian points (Trojan points), and , 60° ahead of and behind the larger body respectively. Another class is the horseshoe orbit, in which objects librate around 180° from the larger body. Objects librating around 0° are called quasi-satellites. An exchange orbit occurs when two co-orbital objects are of similar masses and thus exert a non-negligible influence on each other. The objects can exchange semi-major axes or eccentricities when they approach each other. Parameters Orbital parameters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moons Of Saturn
The moons of Saturn are numerous and diverse, ranging from tiny moonlets only tens of meters across to enormous Titan (moon), Titan, which is larger than the planet Mercury (planet), Mercury. Saturn has 83 natural satellite, moons with confirmed orbits that are not embedded in its Rings of Saturn, 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 (moon), Rhea, are currently in hydrostatic equilibrium. Particularly notable among Saturn's moons are Titan, the second-List of natural satellites, largest moon in the Solar System (after Jupiter's Ganymede (moon), Ganymede), with a Atmosphere of Titan#Composition, nitrogen-rich Earth-like Atmosphere of Titan, atmosphere and a landscape featuring dry river networks and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animation Of Polydeuces's Orbit Relative To Saturn And Dione
Animation is a method by which still figures are manipulated to appear as moving images. In traditional animation, images are drawn or painted by hand on transparent celluloid sheets to be photographed and exhibited on film. Today, most animations are made with computer-generated imagery (CGI). Computer animation can be very detailed 3D animation, while 2D computer animation (which may have the look of traditional animation) can be used for stylistic reasons, low bandwidth, or faster real-time renderings. Other common animation methods apply a stop motion technique to two- and three-dimensional objects like paper cutouts, puppets, or clay figures. A cartoon is an animated film, usually a short film, featuring an exaggerated visual style. The style takes inspiration from comic strips, often featuring anthropomorphic animals, superheroes, or the adventures of human protagonists. Especially with animals that form a natural predator/prey relationship (e.g. cats and mice, coyot ... [...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] |
Methone (moon)
Methone is a small, egg-shaped moon of Saturn that orbits out past Saturn's ring system, between the orbits of Mimas and Enceladus. It was discovered in 2004, though it wasn't until 2012 that it was imaged in detail by the '' Cassini'' spacecraft. History Methone was first discovered by the Cassini Imaging Team and given the temporary designation . Methone is also named (32). The '' Cassini'' spacecraft made two visits to Methone, and its closest approach was made on May 20, 2012 with a minimum distance of from it. The name Methone was approved by the IAU Working Group on Planetary System Nomenclature on January 21, 2005. It was ratified at the IAU General Assembly in 2006. Methone (Greek ''Μεθώνη'') was one of the Alkyonides, the seven beautiful daughters of the Giant Alkyoneus. Orbit Methone's orbit is perturbed by a 14:15 mean-motion resonance with the much larger Mimas. This causes its osculating orbital elements to vary with an amplitude of about in semi-ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrostatic Equilibrium
In fluid mechanics, hydrostatic equilibrium (hydrostatic balance, hydrostasy) is the condition of a fluid or plastic solid at rest, which occurs when external forces, such as gravity, are balanced by a pressure-gradient force. In the planetary physics of Earth, the pressure-gradient force prevents gravity from collapsing the planetary atmosphere into a thin, dense shell, whereas gravity prevents the pressure-gradient force from diffusing the atmosphere into outer space. Hydrostatic equilibrium is the distinguishing criterion between dwarf planets and small solar system bodies, and features in astrophysics and planetary geology. Said qualification of equilibrium indicates that the shape of the object is symmetrically ellipsoid, where any irregular surface features are consequent to a relatively thin solid crust. In addition to the Sun, there are a dozen or so equilibrium objects confirmed to exist in the Solar System. Mathematical consideration For a hydrostatic fluid on Ear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leda (mythology)
In Greek mythology, Leda (; Ancient Greek: Λήδα ) was an Aetolian princess who became a Spartan queen. According to Ovid, she was famed for her beautiful black hair and snowy skin. Her myth gave rise to the popular motif in Renaissance and later art of Leda and the Swan. Family Leda was the daughter of the Aetolian King Thestius hence she was also called Thestias. Her mother was either Leucippe, Deidameia, daughter of Perieres, Eurythemis, daughter of Cleoboea, or Laophonte, daughter of Pleuron.Alcman. ''Fragment 15'' as cited in ''Scholiast'' on Apollonius of Rhodes. ''Argonautica, 1.146'' According to Alcman, Leda's parents were Glaucus and Laophonte while Eumelus attested that they are Sisyphus and Panteiduia or Paneidyia. She married king Tyndareus of Sparta and by him became the mother of Helen of Troy, Clytemnestra, Castor, and Pollux (also called "Polydeuces"). Leda also had three other daughters by Tyndareus: Timandra, Phoebe, and Philonoe. Mythology Le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeus
Zeus or , , ; grc, Δῐός, ''Diós'', label=Genitive case, genitive Aeolic Greek, Boeotian Aeolic and Doric Greek#Laconian, Laconian grc-dor, Δεύς, Deús ; grc, Δέος, ''Déos'', label=Genitive case, genitive el, Δίας, ''Días'' () is the sky father, sky and thunder god in ancient Greek religion, who rules as king of the gods on Mount Olympus. His name is cognate with the first element of his ancient Roman religion, Roman interpretatio graeca, equivalent Jupiter (mythology), Jupiter.''Larousse Desk Reference Encyclopedia'', The Book People, Haydock, 1995, p. 215. His mythology and powers are similar, though not identical, to those of Indo-European deities such as Jupiter, Perkūnas, Perun, Indra, Dyaus, and Zojz (deity), Zojz. Entry: "Dyaus" Zeus is the child of Cronus and Rhea (mythology), Rhea, the youngest of his siblings to be born, though sometimes reckoned the eldest as the others required disgorging from Cronus's stomach. In most traditions, he is m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Castor And Polydeuces
Castor; grc, Κάστωρ, Kástōr, beaver. and Pollux. (or Polydeukes). are twin half-brothers in Greek and Roman mythology, known together as the Dioscuri.; grc, Διόσκουροι, Dióskouroi, sons of Zeus, links=no, from ''Dîos'' ('Zeus') and '' koûroi'' ('boys'). Their mother was Leda, but they had different fathers; Castor was the mortal son of Tyndareus, the king of Sparta, while Pollux was the divine son of Zeus, who raped Leda in the guise of a swan. The pair are thus an example of heteropaternal superfecundation. Though accounts of their birth are varied, they are sometimes said to have been born from an egg, along with their twin sisters Helen of Troy and Clytemnestra. In Latin the twins are also known as the Gemini (literally "twins") or Castores, as well as the Tyndaridae or Tyndarids.. Pollux asked Zeus to let him share his own immortality with his twin to keep them together, and they were transformed into the constellation Gemini. The pair were regarded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greek Mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical cosmology, nature of the world, the lives and activities of List of Greek mythological figures, deities, Greek hero cult, heroes, and List of Greek mythological creatures, mythological creatures, and the origins and significance of the ancient Greeks' own cult (religious practice), cult and ritual practices. Modern scholars study the myths to shed light on the religious and political institutions of ancient Greece, and to better understand the nature of myth-making itself. The Greek myths were initially propagated in an oral tradition, oral-poetic tradition most likely by Minoan civilization, Minoan and Mycenaean Greece, Mycenaean singers starting in the 18th century BC; eventually the myths of the heroes of the Trojan War and its after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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