72-607: Wolfe Creek Crater is a well-preserved meteorite impact crater ( astrobleme ) in Western Australia . It is accessed via the Tanami Road 150 km (93 mi) south of the town of Halls Creek . The crater is central to the Wolfe Creek Meteorite Crater National Park . The crater averages about 875 metres (2,871 ft) in diameter, 60 metres (200 ft) from rim to present crater floor. It
144-562: A 61-kilogram (135 lb) iron meteorite was found in a Sinagua (c. 1100–1200 AD) burial cyst near Camp Verde, Arizona , respectfully wrapped in a feather cloth. A small pallasite was found in a pottery jar in an old burial found at Pojoaque Pueblo , New Mexico. Nininger reports several other such instances, in the Southwest US and elsewhere, such as the discovery of Native American beads of meteoric iron found in Hopewell burial mounds , and
216-672: A blend of rock and metal, the stony-iron meteorites . Modern classification of meteorites is complex. The review paper of Krot et al. (2007) summarizes modern meteorite taxonomy. About 86% of the meteorites are chondrites, which are named for the small, round particles they contain. These particles, or chondrules , are composed mostly of silicate minerals that appear to have been melted while they were free-floating objects in space. Certain types of chondrites also contain small amounts of organic matter , including amino acids , and presolar grains . Chondrites are typically about 4.55 billion years old and are thought to represent material from
288-454: A few centimeters in size that were formed—according to most scientists—by the impacts of large meteorites on Earth's surface. A few researchers have favored tektites originating from the Moon as volcanic ejecta, but this theory has lost much of its support over the last few decades. The diameter of the largest impactor to hit Earth on any given day is likely to be about 40 centimeters (16 inches), in
360-788: A flat, desert plain about 100 kilometres (62 mi) southeast of Dirj (Daraj), Libya . A few years later, a desert enthusiast saw photographs of meteorites being recovered by scientists in Antarctica, and thought that he had seen similar occurrences in northern Africa . In 1989, he recovered about 100 meteorites from several distinct locations in Libya and Algeria. Over the next several years, he and others who followed found at least 400 more meteorites. The find locations were generally in regions known as regs or hamadas : flat, featureless areas covered only by small pebbles and minor amounts of sand. Dark-colored meteorites can be easily spotted in these places. In
432-435: A given year about four metres (13 ft), and in a given century about 20 m (66 ft). These statistics are obtained by the following: Over at least the range from five centimeters (2.0 inches) to roughly 300 meters (980 feet), the rate at which Earth receives meteors obeys a power-law distribution as follows: where N (> D ) is the expected number of objects larger than a diameter of D meters to hit Earth in
504-401: A meteorite shower falls is known as its strewn field . Strewn fields are commonly elliptical in shape, with the major axis parallel to the direction of flight. In most cases, the largest meteorites in a shower are found farthest down-range in the strewn field. Most meteorites are stony meteorites, classed as chondrites and achondrites . Only about 6% of meteorites are iron meteorites or
576-500: A meteorite that was understood by contemporaries to have fallen to the earth from Jupiter , the principal Roman deity. There are reports that a sacred stone was enshrined at the temple that may have been a meteorite. The Black Stone set into the wall of the Kaaba has often been presumed to be a meteorite, but the little available evidence for this is inconclusive. Some Native Americans treated meteorites as ceremonial objects. In 1915,
648-512: A radius of a hundred or more kilometers. Whistling and hissing sounds are also sometimes heard but are poorly understood. Following the passage of the fireball, it is not unusual for a dust trail to linger in the atmosphere for several minutes. As meteoroids are heated during atmospheric entry , their surfaces melt and experience ablation . They can be sculpted into various shapes during this process, sometimes resulting in shallow thumbprint-like indentations on their surfaces called regmaglypts . If
720-546: A rapid rise in commercial collection of meteorites. This process was accelerated when, in 1997, meteorites coming from both the Moon and Mars were found in Libya. By the late 1990s, private meteorite-collecting expeditions had been launched throughout the Sahara. Specimens of the meteorites recovered in this way are still deposited in research collections, but most of the material is sold to private collectors. These expeditions have now brought
792-1103: A shooting star; astronomers call the brightest examples " 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 the 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 silicate minerals ; iron meteorites that are largely composed of ferronickel ; and stony-iron meteorites that contain large amounts of both metallic and rocky material. Modern classification schemes divide meteorites into groups according to their structure, chemical and isotopic composition and mineralogy. "Meteorites" less than ~1 mm in diameter are classified as micrometeorites , however micrometeorites differ from meteorites in that they typically melt completely in
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#1732852424077864-428: A single person, Ivan Wilson. In total, nearly 140 meteorites were found in the region since 1967. In the area of the finds, the ground was originally covered by a shallow, loose soil sitting atop a hardpan layer. During the dustbowl era, the loose soil was blown off, leaving any rocks and meteorites that were present stranded on the exposed surface. Beginning in the mid-1960s, amateur meteorite hunters began scouring
936-414: A space craft crashed there. Meteorite A meteorite is a rock that originated in outer space and has fallen to the surface of a planet or 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 fireball , also known as
1008-605: A year. This is based on observations of bright meteors seen from the ground and space, combined with surveys of near-Earth asteroids . Above 300 m (980 ft) in diameter, the predicted rate is somewhat higher, with a 2 km (1.2 mi) asteroid (one teraton TNT equivalent ) every couple of million years – about 10 times as often as the power-law extrapolation would predict. In 2015, NASA scientists reported that complex organic compounds found in DNA and RNA , including uracil , cytosine , and thymine , have been formed in
1080-456: Is 0.4%. Stony-iron meteorites constitute the remaining 1%. They are a mixture of iron-nickel metal and silicate minerals. One type, called pallasites , is thought to have originated in the boundary zone above the core regions where iron meteorites originated. The other major type of stony-iron meteorites is the mesosiderites . Tektites (from Greek tektos , molten) are not themselves meteorites, but are rather natural glass objects up to
1152-590: Is a meteorite collected after its fall from outer space was observed by people or automated devices. Any other meteorite is called a " find ". There are more than 1,300 documented falls listed in widely used databases, most of which have specimens in modern collections. As of February 2023 , the Meteoritical Bulletin Database had 1372 confirmed falls. Observed meteorite falls are important for several reasons. Material from observed falls has not been subjected to terrestrial weathering, making
1224-432: Is a meteorite collected after its arrival was observed by people or automated devices. Any other meteorite is called a "meteorite find". There are more than 1,100 documented falls listed in widely used databases, most of which have specimens in modern collections. As of January 2019 , the Meteoritical Bulletin Database had 1,180 confirmed falls. Most meteorite falls are collected on the basis of eyewitness accounts of
1296-413: Is currently prohibited by national law, but a number of international hunters continue to remove specimens now deemed national treasures. This new law provoked a small international incident , as its implementation preceded any public notification of such a law, resulting in the prolonged imprisonment of a large group of meteorite hunters, primarily from Russia, but whose party also consisted of members from
1368-410: Is estimated that the meteorite that formed it was about 15 metres (49 ft) in diameter and had a mass of about 14,000 tonnes. For many years it was thought to have been created around 300,000 years ago, but in 2019, following investigations by researchers from Portsmouth University together with Australian and US researchers, it is now estimated to be less than 120,000 years old, placing the event in
1440-606: The Dhofar and Al Wusta regions of Oman, south of the sandy deserts of the Rub' al Khali , had yielded about 5,000 meteorites as of mid-2009. Included among these are a large number of lunar and Martian meteorites, making Oman a particularly important area both for scientists and collectors. Early expeditions to Oman were mainly done by commercial meteorite dealers, however, international teams of Omani and European scientists have also now collected specimens. The recovery of meteorites from Oman
1512-499: The Late Pleistocene . Small numbers of iron meteorites have been found in the vicinity of the crater, as well as larger so-called 'shale-balls', rounded objects made of iron oxide, some weighing as much as 250 kilograms (550 lb). It was brought to the attention of scientists after being spotted during an aerial survey in 1947, investigated on the ground two months later, and reported in publication in 1949. The European name for
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#17328524240771584-690: The asteroid belt that never coalesced into large bodies. Like comets , chondritic asteroids are some of the oldest and most primitive materials in the Solar System . Chondrites are often considered to be "the building blocks of the planets". About 8% of the meteorites are achondrites (meaning they do not contain chondrules), some of which are similar to terrestrial igneous rocks . Most achondrites are also ancient rocks, and are thought to represent crustal material of differentiated planetesimals. One large family of achondrites (the HED meteorites ) may have originated on
1656-422: The genetic code of all life on Earth. These compounds have also occurred spontaneously in laboratory settings emulating conditions in outer space. Until recently, the source of only about 6% of meteorites had been traced to their sources: the Moon, Mars, and asteroid Vesta. Approximately 70% of meteorites found on Earth now appear to originate from break-ups of three asteroids. Most meteorites date from
1728-416: The same source , a collision that occurred somewhere between Jupiter and Mars. One of these fossil meteorites, dubbed Österplana 065 , appears to represent a distinct type of meteorite that is "extinct" in the sense that it is no longer falling to Earth, the parent body having already been completely depleted from the reservoir of near-Earth objects . A "meteorite fall", also called an "observed fall",
1800-522: The 10th Japanese Antarctic Research Expedition found nine meteorites on a blue ice field near the Yamato Mountains . With this discovery, came the realization that movement of ice sheets might act to concentrate meteorites in certain areas. After a dozen other specimens were found in the same place in 1973, a Japanese expedition was launched in 1974 dedicated to the search for meteorites. This team recovered nearly 700 meteorites. Shortly thereafter,
1872-470: The 2013 Chelyabinsk meteorite ) occurred during the 20th century. Presumably, events of such magnitude may happen a few times per century but, especially if it occurred in remote areas, may have gone unreported. For comparison, the largest finds are the 60-ton Hoba meteorite , a 30.8-ton fragment ( Gancedo ) and a 28.8-ton fragment ( El Chaco ) of the Campo del Cielo , and a 30.9-ton fragment ( Ahnighito ) of
1944-708: The American Southwest have been submitted with false find locations, as many finders think it is unwise to publicly share that information for fear of confiscation by the federal government and competition with other hunters at published find sites. Several of the meteorites found recently are currently on display in the Griffith Observatory in Los Angeles, and at UCLA 's Meteorite Gallery. A few meteorites were found in Antarctica between 1912 and 1964. In 1969,
2016-452: The Earth are caused by iron meteoroids, which are most easily able to transit the atmosphere intact. Examples of craters caused by iron meteoroids include Barringer Meteor Crater , Odessa Meteor Crater , Wabar craters , and Wolfe Creek crater ; iron meteorites are found in association with all of these craters. In contrast, even relatively large stony or icy bodies such as small comets or asteroids , up to millions of tons, are disrupted in
2088-597: The Meteorite Observation and Recovery Project, ran from 1971 to 1985. It too recovered a single meteorite, Innisfree , in 1977. Finally, observations by the European Fireball Network , a descendant of the original Czech program that recovered Příbram, led to the discovery and orbit calculations for the Neuschwanstein meteorite in 2002. NASA has an automated system that detects meteors and calculates
2160-690: The Příbram fall, other nations established automated observing programs aimed at studying infalling meteorites. One of these was the Prairie Network , operated by the Smithsonian Astrophysical Observatory from 1963 to 1975 in the midwestern US . This program also observed a meteorite fall, the Lost City chondrite, allowing its recovery and a calculation of its orbit. Another program in Canada,
2232-640: The Stan Australia streaming service original television series with the same name . It was the setting for Arthur Upfield 's 1962 novel The Will of the Tribe . The Wolfe Creek crater has considerable claim to be the second most 'obvious' (i.e. relatively undeformed by erosion) meteorite crater known on Earth, after the famous Barringer Crater in Arizona . The crater is mentioned in the 2010 children's science fiction book Alienology that says (in its universe) that
Wolfe Creek Crater - Misplaced Pages Continue
2304-466: The US as well as several other European countries. Meteorites have figured into human culture since their earliest discovery as ceremonial or religious objects, as the subject of writing about events occurring in the sky and as a source of peril. The oldest known iron artifacts are nine small beads hammered from meteoritic iron. They were found in northern Egypt and have been securely dated to 3200 BC. Although
2376-890: The United States began its own program to search for Antarctic meteorites, operating along the Transantarctic Mountains on the other side of the continent: the Antarctic Search for Meteorites ( ANSMET ) program. European teams, starting with a consortium called "EUROMET" in the 1990/91 season, and continuing with a program by the Italian Programma Nazionale di Ricerche in Antartide have also conducted systematic searches for Antarctic meteorites. The Antarctic Scientific Exploration of China has conducted successful meteorite searches since 2000. A Korean program (KOREAMET)
2448-730: The arid areas of the southwestern United States. To date, thousands of meteorites have been recovered from the Mojave , Sonoran , Great Basin , and Chihuahuan Deserts , with many being recovered on dry lake beds. Significant finds include the three-tonne Old Woman meteorite , currently on display at the Desert Discovery Center in Barstow, California , and the Franconia and Gold Basin meteorite strewn fields; hundreds of kilograms of meteorites have been recovered from each. A number of finds from
2520-406: The atmosphere and fall to Earth as quenched droplets. Extraterrestrial meteorites have been found on the Moon and on Mars. Most meteoroids disintegrate when entering the Earth's atmosphere. Usually, five to ten a year are observed to fall and are subsequently recovered and made known to scientists. Few meteorites are large enough to create large impact craters . Instead, they typically arrive at
2592-516: The atmosphere can appear to be very bright, rivaling the sun in intensity, although most are far dimmer and may not even be noticed during the daytime. Various colors have been reported, including yellow, green, and red. Flashes and bursts of light can occur as the object breaks up. Explosions, detonations, and rumblings are often heard during meteorite falls, which can be caused by sonic booms as well as shock waves resulting from major fragmentation events. These sounds can be heard over wide areas, with
2664-433: The atmosphere, and do not make impact craters. Although such disruption events are uncommon, they can cause a considerable concussion to occur; the famed Tunguska event probably resulted from such an incident. Very large stony objects, hundreds of meters in diameter or more, weighing tens of millions of tons or more, can reach the surface and cause large craters but are very rare. Such events are generally so energetic that
2736-775: The case of several meteorite fields, such as Dar al Gani , Dhofar, and others, favorable light-colored geology consisting of basic rocks (clays, dolomites , and limestones ) makes meteorites particularly easy to identify. Although meteorites had been sold commercially and collected by hobbyists for many decades, up to the time of the Saharan finds of the late 1980s and early 1990s, most meteorites were deposited in or purchased by museums and similar institutions where they were exhibited and made available for scientific research . The sudden availability of large numbers of meteorites that could be found with relative ease in places that were readily accessible (especially compared to Antarctica), led to
2808-399: The course of clearing a field. The result was the discovery of more than 200 new meteorites, mostly stony types. In the late 1960s, Roosevelt County, New Mexico was found to be a particularly good place to find meteorites. After the discovery of a few meteorites in 1967, a public awareness campaign resulted in the finding of nearly 100 new specimens in the next few years, with many being by
2880-404: The crater comes from a nearby creek, which was in turn named after Robert Wolfe (early reports misspell the name as Wolf Creek), a prospector and storekeeper during the gold rush that established the town of Halls Creek. The local Djaru (Jaru) Aboriginal people refer to the crater as Kandimalal . There are multiple Dreaming stories about the formation of the crater. One such story describes
2952-408: The crater's round shape being formed by the passage of a rainbow snake out of the earth, while another snake formed the nearby Sturt Creek. Another story, as told by an Elder, is that one day the crescent moon and the evening star passed very close to each other. The evening star became so hot that it fell to the ground, causing an enormous explosion and flash, followed by a dust cloud. This frightened
Wolfe Creek Crater - Misplaced Pages Continue
3024-525: The discovery of the Winona meteorite in a Native American stone-walled crypt. In medieval China during the Song dynasty , a meteorite strike event was recorded by Shen Kuo in 1064 AD near Changzhou . He reported "a loud noise that sounded like a thunder was heard in the sky; a giant star, almost like the moon, appeared in the southeast" and later finding the crater and the still-hot meteorite within, nearby. Two of
3096-534: The early Solar System and are by far the oldest extant material on Earth. Analysis of terrestrial weathering due to water, salt, oxygen, etc. is used to quantify the degree of alteration that a meteorite has experienced. Several qualitative weathering indices have been applied to Antarctic and desertic samples. The most commonly employed weathering scale, used for ordinary chondrites , ranges from W0 (pristine state) to W6 (heavy alteration). "Fossil" meteorites are sometimes discovered by geologists. They represent
3168-450: The extremely arid climate, there has been relatively little weathering or sedimentation on the surface for tens of thousands of years, allowing meteorites to accumulate without being buried or destroyed. The dark-colored meteorites can then be recognized among the very different looking limestone pebbles and rocks. In 1986–87, a German team installing a network of seismic stations while prospecting for oil discovered about 65 meteorites on
3240-506: The father of meteoritics , was the first to publish in modern Western thought (in 1794) the then audacious idea that meteorites are rocks from space. There were already several documented cases, one of the earliest was the Aegospotami meteorite of 467 BC and which became a landmark for 500 years, of which Diogenes of Apollonia said: With the visible stars revolve stones which are invisible, and for that reason nameless. They often fall on
3312-440: The find a better candidate for scientific study. Historically, observed falls were the most compelling evidence supporting the extraterrestrial origin of meteorites. Furthermore, observed fall discoveries are a better representative sample of the types of meteorites which fall to Earth. For example, iron meteorites take much longer to weather and are easier to identify as unusual objects, as compared to other types. This may explain
3384-424: The fireball or the impact of the object on the ground, or both. Therefore, despite the fact that meteorites fall with virtually equal probability everywhere on Earth, verified meteorite falls tend to be concentrated in areas with higher human population densities such as Europe, Japan, and northern India. A small number of meteorite falls have been observed with automated cameras and recovered following calculation of
3456-457: The first time, including ribose , suggesting that chemical processes on asteroids can produce some organic compounds fundamental to life, and supporting the notion of an RNA world prior to a DNA-based origin of life on Earth. In 2022, a Japanese group reported that they had found adenine (A), thymine (T), guanine (G), cytosine (C) and uracil (U) inside carbon-rich meteorites. These compounds are building blocks of DNA and RNA ,
3528-666: The ground and are extinguished, like the stone star that came down on fire at Aegospotami. showing that the Greeks had a much earlier idea that meteorites are rocks from space. Below is a list of eight confirmed falls pre-1600 AD. However, unlike the Loket (Elbogen) and Ensisheim meteorites, not all are as well-documented. While most confirmed falls involve masses between less than one kg to several kg, some reach 100 kg or more. A few have fragments that total even more than one metric ton . The six largest falls are listed below and five (except
3600-542: The highly weathered remains of meteorites that fell to Earth in the remote past and were preserved in sedimentary deposits sufficiently well that they can be recognized through mineralogical and geochemical studies. The Thorsberg limestone quarry in Sweden has produced an anomalously large number – exceeding one hundred – fossil meteorites from the Ordovician , nearly all of which are highly weathered L-chondrites that still resemble
3672-451: The hot deserts of Australia . Several dozen meteorites had already been found in the Nullarbor region of Western and South Australia . Systematic searches between about 1971 and the present recovered more than 500 others, ~300 of which are currently well characterized. The meteorites can be found in this region because the land presents a flat, featureless, plain covered by limestone . In
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#17328524240773744-572: The impact point. The first of these was the Příbram meteorite , which fell in Czechoslovakia (now the Czech Republic) in 1959. In this case, two cameras used to photograph meteors captured images of the fireball. The images were used both to determine the location of the stones on the ground and, more significantly, to calculate for the first time an accurate orbit for a recovered meteorite. Following
3816-554: The impactor is completely destroyed, leaving no meteorites. (The first example of a stony meteorite found in association with a large impact crater, the Morokweng impact structure in South Africa, was reported in May 2006.) Several phenomena are well documented during witnessed meteorite falls too small to produce hypervelocity craters. The fireball that occurs as the meteoroid passes through
3888-484: The increased proportion of iron meteorites among finds (6.7%), over that among observed falls (4.4%). There is also detailed statistics on falls such as based on meteorite classification . As of January 2019, the Meteoritical Bulletin Database had 1,180 confirmed falls. Statistics by decade are listed in the table in this section. The German physicist Ernst Chladni , sometimes considered as
3960-549: The laboratory under outer space conditions, using starting chemicals, such as pyrimidine , found in meteorites. Pyrimidine and polycyclic aromatic hydrocarbons (PAHs) may have been formed in red giants or in interstellar dust and gas clouds, according to the scientists. In 2018, researchers found that 4.5 billion-year-old meteorites found on Earth contained liquid water along with prebiotic complex organic substances that may be ingredients for life. In 2019, scientists reported detecting sugar molecules in meteorites for
4032-463: The meteoroid maintains a fixed orientation for some time, without tumbling, it may develop a conical "nose cone" or "heat shield" shape. As it decelerates, eventually the molten surface layer solidifies into a thin fusion crust, which on most meteorites is black (on some achondrites , the fusion crust may be very light-colored). On stony meteorites, the heat-affected zone is at most a few mm deep; in iron meteorites, which are more thermally conductive,
4104-437: The more notable meteorites recovered include Tissint and Northwest Africa 7034 . Tissint was the first witnessed Martian meteorite fall in more than fifty years; NWA 7034 is the oldest meteorite known to come from Mars, and is a unique water-bearing regolith breccia. In 1999, meteorite hunters discovered that the desert in southern and central Oman were also favorable for the collection of many specimens. The gravel plains in
4176-787: The oldest recorded meteorite falls in Europe are the Elbogen (1400) and Ensisheim (1492) meteorites. The German physicist, Ernst Florens Chladni , was the first to publish (in 1794) the idea that meteorites might be rocks that originated not from Earth, but from space. His booklet was "On the Origin of the Iron Masses Found by Pallas and Others Similar to it, and on Some Associated Natural Phenomena" . In this he compiled all available data on several meteorite finds and falls concluded that they must have their origins in outer space. The scientific community of
4248-406: The only materials from other planets ever recovered by humans. About 5% of meteorites that have been seen to fall are iron meteorites composed of iron- nickel alloys , such as kamacite and/or taenite . Most iron meteorites are thought to come from the cores of planetesimals that were once molten. As with the Earth, the denser metal separated from silicate material and sank toward the center of
4320-502: The orbit, magnitude, ground track , and other parameters over the southeast USA, which often detects a number of events each night. Until the twentieth century, only a few hundred meteorite finds had ever been discovered. More than 80% of these were iron and stony-iron meteorites, which are easily distinguished from local rocks. To this day, few stony meteorites are reported each year that can be considered to be "accidental" finds. The reason there are now more than 30,000 meteorite finds in
4392-591: The original meteorite under a petrographic microscope , but which have had their original material almost entirely replaced by terrestrial secondary mineralization. The extraterrestrial provenance was demonstrated in part through isotopic analysis of relict spinel grains, a mineral that is common in meteorites, is insoluble in water, and is able to persist chemically unchanged in the terrestrial weathering environment. Scientists believe that these meteorites, which have all also been found in Russia and China, all originated from
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#17328524240774464-481: The parent body of the Vesta Family , although this claim is disputed. Others derive from unidentified asteroids. Two small groups of achondrites are special, as they are younger and do not appear to come from the asteroid belt. One of these groups comes from the Moon, and includes rocks similar to those brought back to Earth by Apollo and Luna programs. The other group is almost certainly from Mars and constitutes
4536-442: The people and a long time passed before they ventured near the crater to see what had happened. When they finally went there, they realised that this was the site where the evening star had fallen to the Earth. The Djaru people named the place "Kandimalal" and it is prominent in art from the region. The crater was featured in the 2005 Australian horror film Wolf Creek , and the sequel in 2013, Wolf Creek 2 . It also features in
4608-569: The planetesimal, forming its core. After the planetesimal solidified, it broke up in a collision with another planetesimal. Due to the low abundance of iron meteorites in collection areas such as Antarctica, where most of the meteoric material that has fallen can be recovered, it is possible that the percentage of iron-meteorite falls is lower than 5%. This would be explained by a recovery bias; laypeople are more likely to notice and recover solid masses of metal than most other meteorite types. The abundance of iron meteorites relative to total Antarctic finds
4680-530: The so-called "Northwest Africa" meteorites. When they get classified, they are named "Northwest Africa" (abbreviated NWA) followed by a number. It is generally accepted that NWA meteorites originate in Morocco, Algeria, Western Sahara, Mali, and possibly even further afield. Nearly all of these meteorites leave Africa through Morocco. Scores of important meteorites, including Lunar and Martian ones, have been discovered and made available to science via this route. A few of
4752-455: The structure of the metal may be affected by heat up to 1 centimetre (0.39 in) below the surface. Reports vary; some meteorites are reported to be "burning hot to the touch" upon landing, while others are alleged to have been cold enough to condense water and form a frost. Meteoroids that disintegrate in the atmosphere may fall as meteorite showers, which can range from only a few up to thousands of separate individuals. The area over which
4824-495: The surface at their terminal velocity and, at most, create a small pit. Large meteoroids may strike the earth with a significant fraction of their escape velocity (second cosmic velocity), leaving behind a hypervelocity impact crater. The kind of crater will depend on the size, composition, degree of fragmentation, and incoming angle of the impactor. The force of such collisions has the potential to cause widespread destruction. The most frequent hypervelocity cratering events on
4896-650: The time responded with resistance and mockery. It took nearly ten years before a general acceptance of the origin of meteorites was achieved through the work of the French scientist Jean-Baptiste Biot and the British chemist, Edward Howard . Biot's study, initiated by the French Academy of Sciences , was compelled by a fall of thousands of meteorites on 26 April 1803 from the skies of L'Aigle, France. Meteorite falls A meteorite fall , also called an observed fall ,
4968-635: The total number of well-described meteorites found in Algeria and Libya to more than 500. Meteorite markets came into existence in the late 1990s, especially in Morocco . This trade was driven by Western commercialization and an increasing number of collectors. The meteorites were supplied by nomads and local people who combed the deserts looking for specimens to sell. Many thousands of meteorites have been distributed in this way, most of which lack any information about how, when, or where they were discovered. These are
5040-589: The use of the metal found in meteorites is also recorded in myths of many countries and cultures where the celestial source was often acknowledged, scientific documentation only began in the last few centuries. Meteorite falls may have been the source of cultish worship . The cult in the Temple of Artemis at Ephesus, one of the Seven Wonders of the Ancient World , possibly originated with the observation and recovery of
5112-582: The world's collections started with the discovery by Harvey H. Nininger that meteorites are much more common on the surface of the Earth than was previously thought. Nininger's strategy was to search for meteorites in the Great Plains of the United States, where the land was largely cultivated and the soil contained few rocks. Between the late 1920s and the 1950s, he traveled across the region, educating local people about what meteorites looked like and what to do if they thought they had found one, for example, in
5184-466: Was launched in 2007 and has collected a few meteorites. The combined efforts of all of these expeditions have produced more than 23,000 classified meteorite specimens since 1974, with thousands more that have not yet been classified. For more information see the article by Harvey (2003). At about the same time as meteorite concentrations were being discovered in the cold desert of Antarctica, collectors discovered that many meteorites could also be found in
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