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Crater Counting
Crater counting is a method for estimating the age of a planet's surface based upon the assumptions that when a piece of planetary surface is new, then it has no impact craters; impact craters accumulate after that at a rate that is assumed known. Consequently, counting how many craters of various sizes there are in a given area allows determining how long they have accumulated and, consequently, how long ago the surface has formed. The method has been calibrated using the ages obtained by radiometric dating of samples returned from the Moon by the Luna programme, Luna and Apollo program, Apollo missions. It has been used to estimate the age of areas on Mars and other planets that were covered by lava flows, on the Moon of areas covered by giant lunar mare, mares, and how long ago areas on the Moons of Jupiter, icy moons of Jupiter and Moons of Saturn, Saturn flooded with new ice. Crater counting and secondary craters The crater counting method requires the presence of independent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low Shield Volcano On Mars With Crater Counting
Low or LOW or lows, may refer to: People * Low (surname), listing people surnamed Low Places * Low, Quebec, Canada * Low, Utah, United States * Lo Wu station (MTR code LOW), Hong Kong; a rail station * Salzburg Airport (ICAO airport code: LOWS), Austria Music * Low (band), an American indie rock group from Duluth, Minnesota * Low (English band), an English duo featuring Frankie Goes to Hollywood guitarist Brian Nash Albums * ''Low'' (David Bowie album), 1977 * ''Low'' (Testament album), 1994 * ''Low'' (Low EP), 1994 Songs * "Low" (Cracker song), 1993 * "Low" (Flo Rida song), 2007 * "Low" (Foo Fighters song), 2002 * "Low" (Juicy J song), 2014 * "Low" (Kelly Clarkson song), 2003 * "Low" (Lenny Kravitz song), 2018 * "Low" (Sara Evans song), 2008 * "Low" (SZA song), 2022 * "Low", by Camp Mulla * "Low", by Coldplay from the 2005 album '' X&Y'' * "Low", by I Prevail from the 2019 album '' Trauma'' * "Low", by Inna from her 2015 self-titled album * "Low", by Marianas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mare Imbrium
Mare Imbrium (Latin ''imbrium'', the "Sea of Showers" or "Sea of Rains") is a vast lunar mare, 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 Protoplanet, proto-planet during the Late Heavy Bombardment. Basaltic lava later flooded the giant Impact crater, crater to form the flat volcanic plain seen today. The basin's age has been estimated using Uranium–lead dating, 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 Lunar mare, 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 would have originally been when it first formed as a result of later events that have altered its surface. Origin Mare Imbrium formed when a proto-planet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation And Evolution Of The Solar System
There is evidence that the formation of the Solar System began about 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud. Most of the collapsing mass collected in the center, forming the Sun, while the rest flattened into a protoplanetary disk out of which the planets, moons, asteroids, and other small Solar System bodies formed. This model, known as the nebular hypothesis, was first developed in the 18th century by Emanuel Swedenborg, Immanuel Kant, and Pierre-Simon Laplace. Its subsequent development has interwoven a variety of scientific disciplines including astronomy, chemistry, geology, physics, and planetary science. Since the dawn of the Space Age in the 1950s and the discovery of exoplanets in the 1990s, the model has been both challenged and refined to account for new observations. The Solar System has evolved considerably since its initial formation. Many moons have formed from circling discs of gas and dust around thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossary Of Meteoritics
This is a glossary of terms used in meteoritics, the science of meteorites. # * 2 Pallas – an asteroid from the asteroid belt and one of the likely parent bodies of the CR meteorites. * 4 Vesta – second-largest asteroid in the asteroid belt and likely source of the HED meteorites. * 221 Eos – an asteroid from the asteroid belt and one of the likely parent bodies of the CO meteorites. * 289 Nenetta – an asteroid from the asteroid belt and one of the likely parent bodies of the angrites. * 3103 Eger – an asteroid from the asteroid belt and one of the likely parent bodies of the aubrites. * 3819 Robinson – an asteroid from the asteroid belt and one of the likely parent bodies of the angrites. * IAB meteorite, IA meteorite – an iron meteorite group now part of the IAB group/complex. * IAB meteorite – an iron meteorite and primitive achondrite of the IAB group/complex. * IAB meteorite, IB meteorite – an iron meteorite group now part of the IAB group/complex. * IC me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteorite
A meteorite is a rock (geology), rock that originated in outer space and has fallen to the surface of a planet or Natural satellite, moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a meteor and forms a Meteoroid#Fireball, fireball, also known as a shooting star; astronomers call the brightest examples "Bolide#Astronomy, bolides". Once it settles on the larger body's surface, the meteor becomes a meteorite. Meteorites vary greatly in size. For geologists, a bolide is a meteorite large enough to create an impact crater. Meteorites that are recovered after being observed as they transit the atmosphere and impact event, impact Earth are called meteorite falls. All others are known as meteorite finds. Meteorites have traditionally been divided into three broad categories: stony meteorites that are rocks, mainly composed of sil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geochronology
Geochronology is the science of Chronological dating, determining the age of rock (geology), rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is provided by tools such as paleomagnetism and stable isotope ratios. By combining multiple geochronological (and biostratigraphic) indicators the precision of the recovered age can be improved. Geochronology is different in application from biostratigraphy, which is the science of assigning sedimentary rocks to a known geological period via describing, cataloging and comparing fossil floral and faunal assemblages. Biostratigraphy does not ''directly'' provide an absolute age determination of a rock, but merely places it within an ''interval'' of time at which that fossil assemblage is known to have coexisted. Both disciplines work together hand in hand, however, to the point where they share the same syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Crater
Secondary craters are impact craters formed by the ejecta that was thrown out of a larger crater. They sometimes form radial crater chains. In addition, secondary craters are often seen as clusters or rays surrounding primary craters. The study of secondary craters exploded around the mid-twentieth century when researchers studying surface craters to predict the age of planetary bodies realized that secondary craters contaminated the crater statistics of a body's crater count. Formation When a velocity-driven extraterrestrial object impacts a relatively stationary body, an impact crater forms. Initial crater(s) to form from the collision are known as primary craters or impact craters. Material expelled from primary craters may form secondary craters (secondaries) under a few conditions: # Primary craters must already be present. # The gravitational acceleration of the extraterrestrial body must be great enough to drive the ejected material back toward the surface. # The velocity by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impact Field Studies Group
The Impact Field Studies Group (IFSG) was a scientific organization emphasizing geologic field research of suspected and confirmed sites of impact craters and impact structures. The group is composed of researchers, professionals and students involved in study of impact sites. IFSG's web site is hosted by the Department of Earth and Planetary Sciences at University of Tennessee, Knoxville. Impact Database IFSG member David Rajmon maintains for the organization a list which was originally called the Suspected Earth Impact Sites (SEIS) list from 2004 to 2009. It was then renamed to simply the Impact Database. The list classifies impact sites as confirmed, most probable, probable, possible, improbable, rejected and proposed (unevaluated). The list retains rejected entries because they tend to be submitted repeatedly. The IFSG Impact Database accepts submissions of proposed new impact sites. However, they require submitters do some significant homework as listed below first. * T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aeolian Processes
Aeolian processes, also spelled eolian, pertain to wind activity in the study of geology and weather and specifically to the wind's ability to shape the surface of the Earth (or other planets). Winds may erosion, erode, transport, and deposit materials. They are effective agents in regions with sparse vegetation, a lack of soil moisture and a large supply of unconsolidated sediments. Although water is a much more powerful eroding force than wind, aeolian processes are important in arid environments such as deserts. The term is derived from the name of the Greek god Aeolus#Aeolus (son of Hippotes), Aeolus, the keeper of the winds. Definition and setting ''Aeolian processes'' are those processes of erosion, Sediment transport, transport, and Deposition (geology), deposition of sediments that are caused by wind at or near the surface of the earth. Sediment deposits produced by the action of wind and the sedimentary structures characteristic of these deposits are also described as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geochronology
Geochronology is the science of Chronological dating, determining the age of rock (geology), rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is provided by tools such as paleomagnetism and stable isotope ratios. By combining multiple geochronological (and biostratigraphic) indicators the precision of the recovered age can be improved. Geochronology is different in application from biostratigraphy, which is the science of assigning sedimentary rocks to a known geological period via describing, cataloging and comparing fossil floral and faunal assemblages. Biostratigraphy does not ''directly'' provide an absolute age determination of a rock, but merely places it within an ''interval'' of time at which that fossil assemblage is known to have coexisted. Both disciplines work together hand in hand, however, to the point where they share the same syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerhard Neukum
Gerhard Neukum (1944-2014) was a German planetary scientist who worked on the chronology of solar system bodies. He obtained a Ph.D. in physics at the Heidelberg University. He was a professor at the Ludwig Maximilian University of Munich and at the Free University of Berlin.Gerhard Neukum 1944-2014 biographical note at American Astronomical Society Neukum was involved in the ESA mission, the joint ESA-NASA mission, the ESA |
Lunar Mare
The lunar maria ( ; mare ) are large, dark, basaltic plains on Earth's Moon, formed by lava flowing into ancient impact basins. They are less reflective than the "highlands" as a result of their iron-rich composition, and hence appear dark to the naked eye. The maria cover about 16% of the lunar surface, mostly on the side visible from Earth. The few maria on the far side are much smaller, residing mostly in very large craters. The traditional nomenclature for the Moon also includes one (ocean), as well as features with the names ('lake'), ('marsh'), and ('bay'). The last three are smaller than maria, but have the same nature and characteristics. The names of maria refer to sea features ( Mare Humorum, Mare Imbrium, Mare Insularum, Mare Nubium, Mare Spumans, Mare Undarum, Mare Vaporum, Oceanus Procellarum, Mare Frigoris), sea attributes ( Mare Australe, Mare Orientale, Mare Cognitum, Mare Marginis), or states of mind ( Mare Crisium, Mare Ingenii, Mare Serenita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
