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Helene (moon)
Helene is a moon of Saturn. It was discovered by Pierre Laques and Jean Lecacheux in 1980 from ground-based observations at Pic du Midi Observatory, and was designated . In 1988 it was officially named after Helen of Troy, who was the granddaughter of Cronus (Saturn) in Greek mythology. Helene is also designated (12), which it was given in 1982, and Dione B,Transactions of the International Astronomical Union, Vol. XVIIIA, 1982 (mentioned in IAUC 3872: ''Satellites of Jupiter and Saturn'', September 30, 1983 because it is co-orbital with Dione and located in its leading Lagrangian point (). It is one of four known trojan moons. Exploration Helene was initially observed from Earth in 1980, and ''Voyager Voyager may refer to: Computing and communications * LG Voyager, a mobile phone model manufactured by LG Electronics * NCR Voyager, a computer platform produced by NCR Corporation * Voyager (computer worm), a computer worm affecting Oracle ...'' flybys of Satu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regolith
Regolith () is a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock. It includes dust, broken rocks, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestrial planets and moons. Etymology The term '' regolith'' combines two Greek words: (), 'blanket', and (), 'rock'. The American geologist George P. Merrill first defined the term in 1897, writing: Earth Earth's regolith includes the following subdivisions and components: * soil or pedolith * alluvium and other transported cover, including that transported by aeolian, glacial, marine, and gravity flow processes. * "saprolith'", generally divided into the ** ''upper saprolite'': completely oxidised bedrock ** ''lower saprolite'': chemically reduced partially weathered rocks ** ''saprock'': fractured bedrock with weathering restricted to fracture margins * volcanic ash and lava flows that are interbedded with unconsolidated material ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trojan Moon
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 th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cassini Helene N00086698 CL
Cassini may refer to: People * Cassini (surname) * Oleg Cassini (1913-2006), American fashion designer :Cassini family: * Giovanni Domenico Cassini (1625–1712), Italian mathematician, astronomer, engineer, and astrologer * Jacques Cassini (1677–1756), French astronomer, son of Giovanni Domenico Cassini * César-François Cassini de Thury (1714–1784), French astronomer and cartographer, son of Jacques Cassini * Jean-Dominique, comte de Cassini (1748–1845), French astronomer, son of César-François Cassini de Thury * Alexandre Henri Gabriel de Cassini (1781–1832), French botanist and naturalist, son of Jean-Dominique de Cassini Planetary science * Cassini's laws on the motion of the Moon * Cassini Division, a gap in the rings of Saturn * ''Cassini–Huygens'', the space mission to examine Saturn and its moons, of which the ''Cassini'' orbiter was a part * Cassini (Martian crater) * Cassini (lunar crater) * 24101 Cassini, an asteroid * 24102 Jacquescassini, another aster ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helene Rev 127 Raw 1
Helene or Hélène may refer to: People *Helene (given name), a Greek feminine given name *Helen of Troy, the daughter of Zeus and Leda *Helene, a figure in Greek mythology who was a friend of Aphrodite and helped her seduce Adonis *Helene (Amazon), a daughter of Tityrus and an Amazon who fought Achilles and died after he seriously wounded her *Helene, the consort of Simon Magus in ''Adversus Haereses'' * Hélène (given name), a feminine given name, the French version of Helen *Hélène (singer), Hélène Rollès Astronomy *Helene (moon), a moon of Saturn Books and film * ''Hélène'' (drama), an 1891 play by Paul Delair * ''Helene'', English edition of German novel by Vicki Baum * ''Hélène'' (film), a 1936 French drama film, based on the novel by Baum Music * ''Hélène'' (opera), an opera by Camille Saint-Saëns 1904 *Polka Hélène in D minor for piano 4 hands by Borodin * ''Hélène'' (album), an album by Roch Voisine 1989 * Hélène (Hélène Rollès album) album by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N00152248 Helene
N, or n, is the fourteenth letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''en'' (pronounced ), plural ''ens''. History One of the most common hieroglyphs, snake, was used in Egyptian writing to stand for a sound like the English , because the Egyptian word for "snake" was ''djet''. It is speculated by many that Semitic people working in Egypt adapted hieroglyphics to create the first alphabet, and that they used the same snake symbol to represent N, because their word for "snake" may have begun with that sound. However, the name for the letter in the Phoenician, Hebrew, Aramaic and Arabic alphabets is ''nun'', which means "fish" in some of these languages. The sound value of the letter was —as in Greek, Etruscan, Latin and modern languages. Use in writing systems represents a dental or alveolar nasal in virtually all languages that use the Latin a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helene Over Saturn
Helene or Hélène may refer to: People *Helene (given name), a Greek feminine given name *Helen of Troy, the daughter of Zeus and Leda *Helene, a figure in Greek mythology who was a friend of Aphrodite and helped her seduce Adonis *Helene (Amazon), a daughter of Tityrus and an Amazon who fought Achilles and died after he seriously wounded her *Helene, the consort of Simon Magus in ''Adversus Haereses'' * Hélène (given name), a feminine given name, the French version of Helen *Hélène (singer), Hélène Rollès Astronomy *Helene (moon), a moon of Saturn Books and film * ''Hélène'' (drama), an 1891 play by Paul Delair * ''Helene'', English edition of German novel by Vicki Baum * ''Hélène'' (film), a 1936 French drama film, based on the novel by Baum Music * ''Hélène'' (opera), an opera by Camille Saint-Saëns 1904 *Polka Hélène in D minor for piano 4 hands by Borodin * ''Hélène'' (album), an album by Roch Voisine 1989 * Hélène (Hélène Rollès album) album by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-Newtonian Fluid
A non-Newtonian fluid is a fluid that does not follow Newton's law of viscosity, i.e., constant viscosity independent of stress. In non-Newtonian fluids, viscosity can change when under force to either more liquid or more solid. Ketchup, for example, becomes runnier when shaken and is thus a non-Newtonian fluid. Many salt solutions and molten polymers are non-Newtonian fluids, as are many commonly found substances such as custard, toothpaste, starch suspensions, corn starch, paint, blood, melted butter, and shampoo. Most commonly, the viscosity (the gradual deformation by shear or tensile stresses) of non-Newtonian fluids is dependent on shear rate or shear rate history. Some non-Newtonian fluids with shear-independent viscosity, however, still exhibit normal stress-differences or other non-Newtonian behavior. In a Newtonian fluid, the relation between the shear stress and the shear rate is linear, passing through the origin, the constant of proportionality being the coefficien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impact Gardening
Impact gardening is the process by which impact events stir the outermost crusts of moons and other celestial objects with no atmospheres. In the particular case of the Moon, this is more often known as lunar gardening. Planetary bodies lacking an atmosphere will generally also lack any erosional processes, with the possible exception of volcanism, and as a result impact debris accumulates at the object's surface as a rough "soil," commonly referred to as regolith. Subsequent impacts, especially by micrometeorite A micrometeorite is a micrometeoroid that has survived entry through the Earth's atmosphere. Usually found on Earth's surface, micrometeorites differ from meteorites in that they are smaller in size, more abundant, and different in composition. T ...s, stir and mix this soil. It had long been estimated that the top centimeter of the lunar surface is overturned every 10 million years. However a 2016 analysis by the LRO satellite of impact ejecta coverage puts the figure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accretion (astrophysics)
In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, in an accretion disk. Most astronomical objects, such as galaxies, stars, and planets, are formed by accretion processes. Overview The accretion model that Earth and the other terrestrial planets formed from meteoric material was proposed in 1944 by Otto Schmidt, followed by the ''protoplanet theory'' of William McCrea (1960) and finally the ''capture theory'' of Michael Woolfson. For details of Kant's position, see In 1978, Andrew Prentice resurrected the initial Laplacian ideas about planet formation and developed the ''modern Laplacian theory''. None of these models proved completely successful, and many of the proposed theories were descriptive. The 1944 accretion model by Otto Schmidt was further developed in a quantitative way in 1969 by Viktor Safronov. He calculated, in detail, the different stages of terrestrial pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
