Mare Imbrium
Mare Imbrium (Latin ''imbrium'', the "Sea of Showers" or "Sea of Rains", "Sea of Tears") is a vast lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System. The Imbrium Basin formed from the collision of a proto-planet during the Late Heavy Bombardment. Basaltic lava later flooded the giant crater to form the flat volcanic plain seen today. The basin's age has been estimated using uranium–lead dating methods to approximately 3.9 billion years ago, and the diameter of the impactor has been estimated to be 250 ± 25 km. The Moon's maria (plural of mare) have fewer features than other areas of the Moon because molten lava pooled in the craters and formed a relatively smooth surface. Mare Imbrium is not as flat as it was originally thought, because later events have altered its surface. Origin Mare Imbrium formed when a proto-planet from the asteroid belt collided with the moon during the Late Heavy Bombardment. The impact i ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Mare Imbrium (LRO)
Mare Imbrium (Latin ''imbrium'', the "Sea of Showers" or "Sea of Rains", "Sea of Tears") is a vast lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System. The Imbrium Basin formed from the collision of a proto-planet during the Late Heavy Bombardment. Basaltic lava later flooded the giant crater to form the flat volcanic plain seen today. The basin's age has been estimated using uranium–lead dating methods to approximately 3.9 billion years ago, and the diameter of the impactor has been estimated to be 250 ± 25 km. The Moon's maria (plural of mare) have fewer features than other areas of the Moon because molten lava pooled in the craters and formed a relatively smooth surface. Mare Imbrium is not as flat as it was originally thought, because later events have altered its surface. Origin Mare Imbrium formed when a proto-planet from the asteroid belt collided with the moon during the Late Heavy Bombardment. The impact i ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Montes Apenninus
Montes Apenninus are a rugged mountain range on the northern part of the Moon's near side. They are named after the Apennine Mountains in Italy. With their formation dating back about 3.9 billion years, Montes Apenninus are fairly old. Description This range forms the southeastern border of the large Mare Imbrium lunar mare and the northwestern border of the Terra Nivium highland region. It begins just to the west of the prominent crater Eratosthenes, which abuts against the southern face of the range. To the west of these mountains is a narrow gap where Mare Imbrium in the north joins Mare Insularum to the south. Further to the west are the Montes Carpatus mountains. From Eratosthenes, the mountains form an arcing chain that gradually bends from east to northeast, ending at Promontorium Fresnel at about latitude 29.5° N. Here is another gap where the Mare Imbrium to the west joins the Mare Serenitatis to the east. At the north end of this gap lie the Montes Caucasus. This ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Lunar Prospector
''Lunar Prospector'' was the third mission selected by NASA for full development and construction as part of the Discovery Program. At a cost of $62.8 million, the 19-month mission was designed for a low polar orbit investigation of the Moon, including mapping of surface composition including Lunar hydrogen deposits, measurements of magnetic and gravity fields, and study of lunar outgassing events. The mission ended July 31, 1999, when the orbiter was deliberately crashed into a crater near the lunar south pole, after the presence of hydrogen was successfully detected. Data from the mission allowed the construction of a detailed map of the surface composition of the Moon, and helped to improve understanding of the origin, evolution, current state, and resources of the Moon. Several articles on the scientific results were published in the journal ''Science''. ''Lunar Prospector'' was managed by NASA Ames Research Center with the prime contractor Lockheed Martin. The Princip ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Lunar Orbiter Program
The Lunar Orbiter program was a series of five uncrewed lunar orbiter missions launched by the United States from 1966 through 1967. Intended to help select Apollo landing sites by mapping the Moon's surface, they provided the first photographs from lunar orbit and photographed both the Moon and Earth. All five missions were successful, and 99 percent of the lunar surface was mapped from photographs taken with a resolution of or better. The first three missions were dedicated to imaging 20 potential crewed lunar landing sites, selected based on Earth-based observations. These were flown at low-inclination orbits. The fourth and fifth missions were devoted to broader scientific objectives and were flown in high-altitude polar orbits. Lunar Orbiter 4 photographed the entire nearside and nine percent of the far side, and Lunar Orbiter 5 completed the far side coverage and acquired medium () and high () resolution images of 36 preselected areas. All of the Lunar Orbiter spacecraft w ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Mass Concentration (astronomy)
In astronomy, astrophysics and geophysics, a mass concentration (or mascon) is a region of a planet's or moon's crust that contains a large positive gravity anomaly. In general, the word "mascon" can be used as a noun to refer to an excess distribution of mass on or beneath the surface of an astronomical body (compared to some suitable average), such as is found around Hawaii on Earth. However, this term is most often used to describe a geologic structure that has a positive gravitational anomaly associated with a feature (e.g. depressed basin) that might otherwise have been expected to have a negative anomaly, such as the "mascon basins" on the Moon. Lunar and Martian mascons The Moon is the most gravitationally "lumpy" major body known in the Solar System. Its largest mascons can cause a plumb bob to hang about a third of a degree off vertical, pointing toward the mascon, and increase the force of gravity by one-half percent. Typical examples of mascon basins on the Moon are t ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Van De Graaff (crater)
Van de Graaff is a crater formation located on the far side of the Moon, on the northeast edge of Mare Ingenii. The crater is named for physicist Robert J. Van de Graaff, whose groundbreaking work includes the invention of the Van de Graaff generator. Description Van de Graaff has the appearance of two merged craters, approximately in a figure-8 shape with no intervening rim separating the two halves. The crater Birkeland is attached to the southeast rim, nestling against the slightly narrower "waist" of the formation. To the north is Aitken, and Nassau lies to the east. The outer rim has some terracing along the southwest wall, but is generally in a worn and eroded state. A pair of craterlets overlay the southeast rim, next to Birkeland. There are also several small craters on the interior floor of Van de Graaff. The southwest section has a central peak, while the northeast floor is slightly smoother in form. Orbital studies of the Moon have demonstrated that there is a ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Lithosphere
A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust (geology), crust and the portion of the upper mantle (geology), mantle that behaves elastically on time scales of up to thousands of years or more. The crust and upper mantle (Earth), upper mantle are distinguished on the basis of chemistry and mineralogy. Earth's lithosphere Earth's lithosphere, which constitutes the hard and rigid outer vertical layer of the Earth, includes the crust and the uppermost mantle. The lithosphere is underlain by the asthenosphere which is the weaker, hotter, and deeper part of the upper mantle. The lithosphere–asthenosphere boundary is defined by a difference in response to stress. The lithosphere remains rigid for very long periods of geologic time in which it deforms elastically and through brittle failure, while the asthenosphere deforms viscously and accommodates strain through plasticity (physics), pl ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Grove Karl Gilbert
Grove Karl Gilbert (May 6, 1843 – May 1, 1918), known by the abbreviated name G. K. Gilbert in academic literature, was an American geologist. Biography Gilbert was born in Rochester, New York and graduated from the University of Rochester. During the American Civil War, he was twice listed for the draft, but his name was drawn neither time. In 1871, he joined George M. Wheeler's geographical survey as its first geologist. Rockies geologist He then joined the Powell Survey of the Rocky Mountain Region in 1874, becoming Powell's primary assistant, and stayed with the survey until 1879. During this time he published an important monograph, ''The Geology of the Henry Mountains'' (1877). After the creation of the U.S. Geological Survey in 1879, he was appointed to the position of Senior Geologist and worked for the USGS until his death (including a term as acting director). Gilbert published a study of the former ancient Lake Bonneville in 1890 (the lake existed during the P ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Ejecta
Ejecta (from the Latin: "things thrown out", singular ejectum) are particles ejected from an area. In volcanology, in particular, the term refers to particles including pyroclastic materials (tephra) that came out of a volcanic explosion and magma eruption volcanic vent, or crater, has traveled through the air or under water, and fell back on the ground surface or on the ocean floor. Volcanology Typically in volcanology, ejecta is a result of explosive eruptions. In an explosive eruption, large amounts of gas are dissolved in extremely viscous lava; this lava froths to the surface until the material is expelled rapidly due to the trapped pressure. Sometimes in such an event a lava plug or volcanic neck forms from lava that solidifies inside a volcano's vent, causing heat and pressure to build up to an extreme with no way to escape. When the blockage breaks and cannot sustain itself any longer, a more violent eruption occurs, which allows materials to be ejected out of the volc ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Plato (crater)
Plato is a lava-filled lunar impact crater on the Moon. Its diameter is 101 km. It was named after ancient Greek philosopher Plato. It is located on the northeastern shore of the Mare Imbrium, at the western extremity of the Montes Alpes mountain range. In the mare to the south are several rises collectively named the Montes Teneriffe. To the north lies the wide stretch of the Mare Frigoris. East of the crater, among the Montes Alpes, are several rilles collectively named the Rimae Plato. The age of Plato is about 3.84 billion years, only slightly younger than the Mare Imbrium to the south. The rim is irregular with 2-km-tall jagged peaks that project prominent shadows across the crater floor when the Sun is at a low angle. Sections of the inner wall display signs of past slumping, most notably a large triangular slide along the western side. The rim of Plato is circular, but from the Earth it appears oval due to foreshortening. The flat floor of Plato has a relatively low ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |