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Rings Of Rhea
Rhea, the second-largest moon of Saturn, may have a tenuous ring system consisting of three narrow, relatively dense bands within a particulate disk. This would be the first discovery of rings around a moon. The potential discovery was announced in the journal ''Science'' on March 6, 2008. In November 2005 the ''Cassini'' orbiter found that Saturn's magnetosphere is depleted of energetic electrons near Rhea. According to the discovery team, the pattern of depletion is best explained by assuming the electrons are absorbed by solid material in the form of an equatorial disk of particles perhaps several decimeters to approximately a meter in diameter and that contains several denser rings or arcs. Subsequent targeted optical searches of the putative ring plane from several angles by ''Cassinis narrow-angle camera failed to find any evidence of the expected ring material, and in August 2010 it was announced that Rhea was unlikely to have rings, and that the reason for the depletion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tethys (moon)
Tethys (), or Saturn III, is a mid-sized moon of Saturn about across. It was discovered by G. D. Cassini in 1684 and is named after the titan Tethys of Greek mythology. Tethys has a low density of 0.98 g/cm3, the lowest of all the major moons in the Solar System, indicating that it is made of water ice with just a small fraction of rock. This is confirmed by the spectroscopy of its surface, which identified water ice as the dominant surface material. A small amount of an unidentified dark material is present as well. The surface of Tethys is very bright, being the second-brightest of the moons of Saturn after Enceladus, and neutral in color. Tethys is heavily cratered and cut by a number of large faults/graben. The largest impact crater, Odysseus, is about 400 km in diameter, whereas the largest graben, Ithaca Chasma, is about 100 km wide and more than 2000 km long. These two largest surface features may be related. A small part of the surface is covered ... [...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] |
Subsatellite
A subsatellite, also known as a submoon, or moonmoon, is a "moon of a moon" or a hypothetical natural satellite that orbits the moon of a planet. It is inferred from the empirical study of natural satellites in the Solar System that subsatellites may be rare, albeit possible, 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, which could theoretically host a subsatellite. Nonetheless, aside from human-launched satellites in temporary lunar orbit, no notable subsatellite is known in the Solar System or beyond. In most cases, the tidal effects of the planet would make such a system unstable. Terminology Terms used in scientific literature for subsatellites include "submoons" and "moon-moons". Colloquial terms that have been suggested include moonitos, moonettes, and moooons. Possible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rings Of Saturn
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] |
Titan (moon)
Titan is the largest moon of Saturn and the second-largest natural satellite in the Solar System. It is the only moon known to have a dense atmosphere, and is the only known object in space other than Earth on which clear evidence of stable bodies of surface liquid has been found. Titan is one of the seven gravitationally rounded moons in orbit around Saturn, and the second most distant from Saturn of those seven. Frequently described as a planet-like moon, Titan is 50% larger (in diameter) than Earth's Moon and 80% more massive. It is the second-largest moon in the Solar System after Jupiter's moon Ganymede, and is larger than the planet Mercury, but only 40% as massive. Discovered in 1655 by the Dutch astronomer Christiaan Huygens, Titan was the first known moon of Saturn, and the sixth known planetary satellite (after Earth's moon and the four Galilean moons of Jupiter). Titan orbits Saturn at 20 Saturn radii. From Titan's surface, Saturn subtends an arc of 5.09 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhea PIA13422 Center
Rhea may refer to: * Rhea (bird), genus of flightless birds native to South America * Rhea (mythology), a Titan in Greek mythology It may also refer to: People *Rhea (name), list of people with this name Mythology * Rhea Silvia, in Roman mythology the mother of the twins Romulus and Remus * Rhea (mother of Aventinus), mother of Aventinus by Hercules * Rhea or Riadh, Celtic mythological hero Science and technology * Rhea (moon), a moon of Saturn * 577 Rhea, an asteroid * Green ramie or rhea, a bast fibre plant * Rhea (pipeline), a set of scripts in R for the analysis of microbial profiles Places * Rhea County, Tennessee * Rhea Springs, Tennessee, a defunct town * Île de Ré or Rhea, an island in France Music * ''Rhea'', a 1908 opera by Spyridon Samaras * ''Rhea'', a 1988 composition for 12 saxophones by Francisco Guerrero Marín * "Rhea", a song on the 1997 album '' Did Tomorrow Come...'' by Polish heavy metal band Sirrah * ''Rheia'' (album), a 2016 album by Belgian band O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rings Of Uranus
The rings of Uranus are intermediate in complexity between the more extensive set around Saturn and the simpler systems around Jupiter and Neptune. The rings of Uranus were discovered on March 10, 1977, by James L. Elliot, Edward W. Dunham, and Jessica Mink. William Herschel had also reported observing rings in 1789; modern astronomers are divided on whether he could have seen them, as they are very dark and faint.(re study by Stuart Eves) By 1977, nine distinct rings were identified. Two additional rings were discovered in 1986 in images taken by the ''Voyager 2'' spacecraft, and two outer rings were found in 2003–2005 in Hubble Space Telescope photos. In the order of increasing distance from the planet the 13 known rings are designated 1986U2R/ζ, 6, 5, 4, α, β, η, γ, δ, λ, ε, ν and μ. Their radii range from about 38,000 km for the 1986U2R/ζ ring to about 98,000 km for the μ ring. Additional faint dust bands and incomplete arcs may exist between the main ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhea N1516373983 1-RHCL1CL2
Rhea may refer to: * Rhea (bird), genus of flightless birds native to South America * Rhea (mythology), a Titan in Greek mythology It may also refer to: People *Rhea (name), list of people with this name Mythology * Rhea Silvia, in Roman mythology the mother of the twins Romulus and Remus * Rhea (mother of Aventinus), mother of Aventinus by Hercules * Rhea or Riadh, Celtic mythological hero Science and technology * Rhea (moon), a moon of Saturn * 577 Rhea, an asteroid * Green ramie or rhea, a bast fibre plant * Rhea (pipeline), a set of scripts in R for the analysis of microbial profiles Places * Rhea County, Tennessee * Rhea Springs, Tennessee, a defunct town * Île de Ré or Rhea, an island in France Music * ''Rhea'', a 1908 opera by Spyridon Samaras * ''Rhea'', a 1988 composition for 12 saxophones by Francisco Guerrero Marín * "Rhea", a song on the 1997 album '' Did Tomorrow Come...'' by Polish heavy metal band Sirrah * ''Rheia'' (album), a 2016 album by Belgian band O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enceladus (moon)
Enceladus is the sixth-largest moon of Saturn (19th largest in the Solar System). It is about in diameter, about a tenth of that of Saturn's largest moon, Titan. Enceladus is mostly covered by fresh, clean ice, making it one of the most reflective bodies of the Solar System. Consequently, its surface temperature at noon only reaches , far colder than a light-absorbing body would be. Despite its small size, Enceladus has a wide range of surface features, ranging from old, heavily cratered regions to young, tectonically deformed terrain. Enceladus was discovered on August 28, 1789, by William Herschel, but little was known about it until the two Voyager spacecraft, ''Voyager 1'' and ''Voyager 2'', flew by Saturn in 1980 and 1981. In 2005, the spacecraft '' Cassini'' started multiple close flybys of Enceladus, revealing its surface and environment in greater detail. In particular, ''Cassini'' discovered water-rich plumes venting from the south polar region. Cryovolc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hill Sphere
The Hill sphere of an astronomical body is the region in which it dominates the attraction of satellites. To be retained by a planet, a moon must have an orbit that lies within the planet's Hill sphere. That moon would, in turn, have a Hill sphere of its own. Any object within that distance would tend to become a satellite of the moon, rather than of the planet itself. One simple view of the extent of the Solar System is the Hill sphere of the Sun with respect to local stars and the galactic nucleus. In more precise terms, the Hill sphere approximates the gravitational sphere of influence of a smaller body in the face of perturbations from a more massive body. It was defined by the American astronomer George William Hill, based on the work of the French astronomer Édouard Roche. In the example to the right, the Earth's Hill sphere extends between the Lagrange points and , which lie along the line of centers of the two bodies. The region of influence of the smaller body is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
