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Multi-ringed Impact Basins
A multi-ringed basin (also a multi-ring impact basin) is not a simple bowl-shaped crater, or a peak ring crater, but one containing multiple concentric topographic rings; a multi-ringed basin could be described as a massive impact crater, surrounded by circular chains of mountains resembling rings on a bull's-eye. A multi-ringed basin may have an area of many thousands of square kilometres. An impact crater of diameter bigger than about is referred to as a ''basin''. __TOC__ The structure of multi-ring basins In adjacent rings, the ratio of the diameters approximates :1 ≈ 1.41 to 1.''Moons & Planets'', William K. Hartmann, 2005, p.255ff Formation To start, a peak ring crater has * one peak-ring, i.e., a crater rim, which is generally circular, ''and'' * a mountainous region which surrounds the basin center. A multi-ringed basin has an important difference, which is multiple peak-rings. In extremely large collisions, following the impact the rebound of the surface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valhalla Basin From Voyager 1
In Norse mythology Valhalla (;) is the anglicised name for non, Valhǫll ("hall of the slain").Orchard (1997:171–172) It is described as a majestic hall located in Asgard and presided over by the god Odin. Half of those who die in combat enter Valhalla, while the other half are chosen by the goddess Freyja to reside in Fólkvangr. The masses of those killed in combat (known as the Einherjar) along with various legendary Germanic heroes and kings, live in Valhalla until Ragnarök when they will march out of its many doors to fight in aid of Odin against the jötnar. Valhalla is attested in the ''Poetic Edda'', compiled in the 13th century from earlier traditional sources, in the ''Prose Edda'' (written in the 13th century by Snorri Sturluson), in ''Heimskringla'' (also written in the 13th century by Snorri Sturluson), and in stanzas of an anonymous 10th century poem commemorating the death of Eric Bloodaxe known as ''Eiríksmál'' as compiled in ''Fagrskinna''. Valhall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moons Of Jupiter
There are 82 known moons of Jupiter, not counting a number of moonlets likely shed from the inner moons. All together, they form a satellite system which is called the Jovian system. The most massive of the moons are the four Galilean moons: Io, Europa, Ganymede, and Callisto, which were independently discovered in 1610 by Galileo Galilei and Simon Marius and were the first objects found to orbit a body that was neither Earth nor the Sun. Much more recently, beginning in 1892, dozens of far smaller Jovian moons have been detected and have received the names of lovers (or other sexual partners) or daughters of the Roman god Jupiter or his Greek equivalent Zeus. The Galilean moons are by far the largest and most massive objects to orbit Jupiter, with the remaining 78 known moons and the rings together composing just 0.003% of the total orbiting mass. Of Jupiter's moons, eight are regular satellites with prograde and nearly circular orbits that are not greatly inclined wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar And Planetary Institute
The Lunar and Planetary Institute (LPI) is a scientific research institute dedicated to study of the Solar System, its formation, evolution, and current state. The Institute is part of the Universities Space Research Association (USRA) and is supported by the Science Mission Directorate of the National Aeronautics and Space Administration (NASA). Located at 3600 Bay Area Boulevard in Houston, Texas, the LPI maintains an extensive collection of lunar and planetary data, carries out education and public outreach programs, and offers meeting coordination and publishing services. The LPI sponsors and organizes several workshops and conferences throughout the year, including the Lunar and Planetary Science Conference (LPSC) held in March in the Houston area. History In his March 1968 speech at the Manned Spacecraft Center (MSC) in Houston, Texas, President Lyndon B. Johnson announced the formation of the Lunar Science Institute (LSI). "We will welcome here all who are interested i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valhalla (crater)
Located on Jupiter's moon Callisto, Valhalla is the largest multi-ring impact crater in the Solar System. It is named after Valhalla, the hall where warriors are taken after death in Norse mythology. Valhalla consists of a bright central region 360 km across, an inner ridge and trough zone, and striking concentric rings extending up to about 1,900 km from the center. Several large impact craters and crater chains are superimposed on Valhalla. The multi-ring system may have formed as semi-liquid or liquid material underlying the brittle lithosphere punctured by the impactor slumped towards the center of the crater following the impact. General description Valhalla is the largest multi-ring basin on Callisto and in the Solar System (with diameter up to 3,800 km). It was discovered by the Voyager probes in 1979–80 and is located on the leading hemisphere of Callisto, in its Jupiter facing quadrant slightly to the north of the equator (at about 18°N latitude ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Callisto (moon)
Callisto (), or Jupiter IV, is the second-largest moon of Jupiter, after Ganymede. It is the third-largest moon in the Solar System after Ganymede and Saturn's largest moon Titan, and the largest object in the Solar System that may not be properly differentiated. Callisto was discovered in 1610 by Galileo Galilei. With a diameter of , Callisto is about 99% the diameter of the planet Mercury, but only about a third of its mass. It is the fourth Galilean moon of Jupiter by distance, with an orbital radius of about . It is not in an orbital resonance like the three other Galilean satellites— Io, Europa, and Ganymede—and is thus not appreciably tidally heated. Callisto's rotation is tidally locked to its orbit around Jupiter, so that the same hemisphere always faces inward. Because of this, there is a sub-Jovian point on Callisto's surface, from which Jupiter would appear to hang directly overhead. It is less affected by Jupiter's magnetosphere than the other inner satell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Satellite
A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are often colloquially referred to as ''moons'', a derivation from the Moon of Earth. In the Solar System, there are six planetary satellite systems containing 209 known natural satellites altogether. Seven objects commonly considered dwarf planets by astronomers are also known to have natural satellites: , Pluto, Haumea, , Makemake, , and Eris. , there are 442 other minor planets known to have natural satellites. A planet usually has at least around 10,000 times the mass of any natural satellites that orbit it, with a correspondingly much larger diameter. The Earth–Moon system is a unique exception in the Solar System; at 3,474 kilometres (2,158 miles) across, the Moon is 0.273 times the diameter of Earth and about of its mass. The next largest ratios are the Neptune–Tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jupiter
Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth the mass of the Sun. Jupiter is the List of brightest natural objects in the sky, third brightest natural object in the Earth's night sky after the Moon and Venus, and it has been observed since Pre-history, prehistoric times. It was named after the Jupiter (mythology), Roman god Jupiter, the king of the gods. Jupiter is primarily composed of hydrogen, but helium constitutes one-quarter of its mass and one-tenth of its volume. It probably has a rocky core of heavier elements, but, like the other giant planets in the Solar System, it lacks a well-defined solid surface. The ongoing contraction of Jupiter's interior generates more heat than it receives from the Sun. Because of its rapid rotation, the planet' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caloris Montes
The Caloris Montes (Latin for "Heat's Mountains") are a range of mountains on Mercury. They are a system of linear hills and valleys that extend more than 1000 km to the northeast from the mountainous rim of Caloris Basin in the Shakespeare quadrangle (H-3). The range consists of numerous rectilinear massif In geology, a massif ( or ) is a section of a planet's crust that is demarcated by faults or flexures. In the movement of the crust, a massif tends to retain its internal structure while being displaced as a whole. The term also refers to a ...s 1 to 3 km high and about 10 to 50 km long, mostly elongated radially from the center of the basin and separated by hackly-floored, radial troughs and gouge-like structures. The surfaces of the massifs are hackly. They are best developed along the inner edge of the basin where steep inward-facing scarps are common, grading outward into smaller massifs and blocks. The range marks the crest of most prominent ring structure ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caloris Basin
Caloris Planitia is a plain within a large impact basin on Mercury, informally named Caloris, about in diameter. It is one of the largest impact basins in the Solar System. "Calor" is Latin for "heat" and the basin is so-named because the Sun is almost directly overhead every second time Mercury passes perihelion. The crater, discovered in 1974, is surrounded by the Caloris Montes, a ring of mountains approximately tall. Appearance Caloris was discovered on images taken by the '' Mariner 10'' probe in 1974. Its name was suggested by Brian O'Leary, astronaut and member of the ''Mariner 10'' imagery team. It was situated on the terminator—the line dividing the daytime and nighttime hemispheres—at the time the probe passed by, and so half of the crater could not be imaged. Later, on January 15, 2008, one of the first photos of the planet taken by the '' MESSENGER'' probe revealed the crater in its entirety. The basin was initially estimated to be about in diameter, thoug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury (planet)
Mercury is the smallest planet in the Solar System and the closest to the Sun. Its orbit around the Sun takes 87.97 Earth days, the shortest of all the Sun's planets. It is named after the Roman god ' ( Mercury), god of commerce, messenger of the gods, and mediator between gods and mortals, corresponding to the Greek god Hermes (). Like Venus, Mercury orbits the Sun within Earth's orbit as an inferior planet, and its apparent distance from the Sun as viewed from Earth never exceeds 28°. This proximity to the Sun means the planet can only be seen near the western horizon after sunset or the eastern horizon before sunrise, usually in twilight. At this time, it may appear as a bright star-like object, but is more difficult to observe than Venus. From Earth, the planet telescopically displays the complete range of phases, similar to Venus and the Moon, which recurs over its synodic period of approximately 116 days. The synodic proximity of Mercury to Earth makes Mercury most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evander (crater)
Dione () is a moons of Saturn, moon of Saturn. It was discovered by Italian astronomer Giovanni Domenico Cassini in 1684. It is named after the Titan (mythology), Titaness Dione (Titaness), Dione of Greek mythology. It is also designated Saturn IV. Name Giovanni Domenico Cassini named the four moons he discovered (Tethys (moon), Tethys, Dione, Rhea (moon), Rhea and Iapetus (moon), Iapetus) ''Sidera Lodoicea'' ("the stars of Louis") to honor king Louis XIV of France, Louis XIV. Cassini found Dione in 1684 using a large aerial telescope he set up on the grounds of the Paris Observatory. The satellites of Saturn were not named until 1847, when William Herschel's son John Herschel published ''Results of Astronomical Observations made at the Cape of Good Hope,'' suggesting that the names of the Titan (mythology), Titans (sisters and brothers of Cronus) be used. Orbit Dione orbits Saturn with a semimajor axis about 2% less than that of the Moon. However, reflecting Saturn's g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dione (moon)
Dione () is a moon of Saturn. It was discovered by Italian astronomer Giovanni Domenico Cassini in 1684. It is named after the Titaness Dione of Greek mythology. It is also designated Saturn IV. Name Giovanni Domenico Cassini named the four moons he discovered ( Tethys, Dione, Rhea and Iapetus) ''Sidera Lodoicea'' ("the stars of Louis") to honor king Louis XIV. Cassini found Dione in 1684 using a large aerial telescope he set up on the grounds of the Paris Observatory. The satellites of Saturn were not named until 1847, when William Herschel's son John Herschel published ''Results of Astronomical Observations made at the Cape of Good Hope,'' suggesting that the names of the Titans (sisters and brothers of Cronus) be used. Orbit Dione orbits Saturn with a semimajor axis about 2% less than that of the Moon. However, reflecting Saturn's greater mass (95 times that of Earth), Dione's orbital period is one tenth that of the Moon. Dione is currently in a 1:2 mean-motion or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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