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A meteorite is a rock that originated in outer space and has fallen to the surface of a planet or
moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...
. When the original object enters the atmosphere, various factors such as
friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete list. The study of t ...
, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a
meteor A meteor, known colloquially as a shooting star, is a glowing streak of a small body (usually meteoroid) going through Earth's atmosphere, after being heated to incandescence by collisions with air molecules in the upper atmosphere, creating a ...
and forms a fireball, also known as 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 An impact crater is a depression (geology), depression in the surface of a solid astronomical body formed by the hypervelocity impact event, impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal c ...
. Meteorites that are recovered after being observed as they transit the atmosphere and impact Earth are called
meteorite fall A meteorite fall, also called an observed fall, is a meteorite collected after its fall from outer space, that was also observed by people or automated devices. Any other meteorite is called a "meteorite find, find". There are more than 1,300 d ...
s. 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 mineral Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, the crystalline forms of silica (silicon dio ...
s; iron meteorites that are largely composed of ferronickel; and stony-iron meteorites that contain large amounts of both metallic and rocky material. Modern
classification Classification is the activity of assigning objects to some pre-existing classes or categories. This is distinct from the task of establishing the classes themselves (for example through cluster analysis). Examples include diagnostic tests, identif ...
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 the atmosphere and fall to Earth as quenched droplets. Extraterrestrial meteorites have been found on the Moon and on Mars. Most space rocks crashing into
Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
come from a single source. The origin of most meteorites can be traced to just a handful of asteroid breakup events – and possibly even individual
asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
s.


Fall phenomena

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 crater An impact crater is a depression (geology), depression in the surface of a solid astronomical body formed by the hypervelocity impact event, impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal c ...
s. Instead, they typically arrive at 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 In celestial mechanics, escape velocity or escape speed is the minimum speed needed for an object to escape from contact with or orbit of a primary body, assuming: * Ballistic trajectory – no other forces are acting on the object, such as ...
(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 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 The Odessa Meteor Crater is a meteorite impact crater, crater in the southwestern part of Ector County, Texas, Ector County, southwest of the city of Odessa, Texas, Odessa of West Texas, United States. It is accessible approximately south of I ...
,
Wabar craters The Wabar craters are impact craters located in Saudi Arabia first brought to the attention of Western scholars by British Arabist, explorer, writer and Colonial Office intelligence officer St John Philby, who discovered them while searching f ...
, 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
comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...
s or
asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
s, up to millions of tons, are disrupted in 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 The Tunguska event was a large explosion of between 3 and 50 TNT equivalent, megatons that occurred near the Podkamennaya Tunguska River in Yeniseysk Governorate (now Krasnoyarsk Krai), Russia, on the morning of 30 June 1908. The explosion over ...
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 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 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 wave In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a me ...
s resulting from major fragmentation events. These sounds can be heard over wide areas, with 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 Atmospheric entry (sometimes listed as Vimpact or Ventry) is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. Atmospheric entry may be ''uncontrolled entr ...
, their surfaces melt and experience
ablation Ablation ( – removal) is the removal or destruction of something from an object by vaporization, chipping, erosion, erosive processes, or by other means. Examples of ablative materials are described below, including spacecraft material for as ...
. They can be sculpted into various shapes during this process, sometimes resulting in shallow thumbprint-like indentations on their surfaces called regmaglypts. If 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, the structure of the metal may be affected by heat up to 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 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.


Classification

Most meteorites are stony meteorites, classed as
chondrite A chondrite is a stony (non-metallic) meteorite that has not been modified by either melting or planetary differentiation, differentiation of the parent body. They are formed when various types of dust and small grains in the early Solar Syste ...
s and achondrites. Only about 6% of meteorites are iron meteorites or 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,Meteoritical Bulletin Database
. Lpi.usra.edu (1 January 2011). Retrieved on 17 December 2011.
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 Organic matter, organic material or natural organic matter is the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have come fro ...
, including
amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...
s, and presolar grains. Chondrites are typically about 4.55 billion years old and are thought to represent material from the
asteroid belt The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...
that never coalesced into large bodies. Like
comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...
s, chondritic asteroids are some of the oldest and most primitive materials in the
Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...
. 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 rock Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial ...
s. 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 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 Apollo is one of the Twelve Olympians, Olympian deities in Ancient Greek religion, ancient Greek and Ancient Roman religion, Roman religion and Greek mythology, Greek and Roman mythology. Apollo has been recognized as a god of archery, mu ...
and Luna programs. The other group is almost certainly from
Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...
and constitutes 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 Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...
alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...
s, 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 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 is 0.4%. Stony-iron meteorites constitute the remaining 1%. They are a mixture of iron-nickel metal and
silicate A silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula , where . The family includes orthosilicate (), metasilicate (), and pyrosilicate (, ). The name is also used ...
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 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 The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...
as volcanic ejecta, but this theory has lost much of its support over the last few decades.


Frequency

The diameter of the largest impactor to hit Earth on any given day is likely to be about , in a given year about , and in a given century about . These statistics are obtained by the following: Over at least the range from to roughly , the rate at which Earth receives meteors obeys a power-law distribution as follows: :N(>D) = 37 D^\ where ''N'' (>''D'') is the expected number of objects larger than a diameter of ''D'' meters to hit Earth in a year. This is based on observations of bright meteors seen from the ground and space, combined with surveys of near-Earth asteroids. Above in diameter, the predicted rate is somewhat higher, with a 2 km (1.2 mi) asteroid (one teraton
TNT equivalent TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. A ton of TNT equivalent is a unit of energy defined by convention to be (). It is the approximate energy released in the de ...
) every couple of million yearsabout 10 times as often as the power-law extrapolation would predict.


Chemistry

In 2015, NASA scientists reported that complex
organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...
s found in
DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...
and
RNA Ribonucleic acid (RNA) is a polymeric molecule that is essential for most biological functions, either by performing the function itself (non-coding RNA) or by forming a template for the production of proteins (messenger RNA). RNA and deoxyrib ...
, including
uracil Uracil () (nucleoside#List of nucleosides and corresponding nucleobases, symbol U or Ura) is one of the four nucleotide bases in the nucleic acid RNA. The others are adenine (A), cytosine (C), and guanine (G). In RNA, uracil binds to adenine via ...
,
cytosine Cytosine () (symbol C or Cyt) is one of the four nucleotide bases found in DNA and RNA, along with adenine, guanine, and thymine ( uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attac ...
, and
thymine Thymine () (symbol T or Thy) is one of the four nucleotide bases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The others are adenine, guanine, and cytosine. Thymine is also known as 5-methyluracil, a pyrimidine ...
, have been formed in the laboratory under outer space conditions, using starting chemicals, such as
pyrimidine Pyrimidine (; ) is an aromatic, heterocyclic, organic compound similar to pyridine (). One of the three diazines (six-membered heterocyclics with two nitrogen atoms in the ring), it has nitrogen atoms at positions 1 and 3 in the ring. The oth ...
, 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 the first time, including
ribose Ribose is a simple sugar and carbohydrate with molecular formula C5H10O5 and the linear-form composition H−(C=O)−(CHOH)4−H. The naturally occurring form, , is a component of the ribonucleotides from which RNA is built, and so this comp ...
, suggesting that chemical processes on
asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
s can produce some organic compounds fundamental to life, and supporting the notion of an RNA world prior to a DNA-based
origin of life Abiogenesis is the natural process by which life arises from abiotic component, non-living matter, such as simple organic compounds. The prevailing scientific hypothesis is that the transition from non-living to organism, living entities on ...
on Earth. In 2022, a Japanese group reported that they had found
adenine Adenine (, ) (nucleoside#List of nucleosides and corresponding nucleobases, symbol A or Ade) is a purine nucleotide base that is found in DNA, RNA, and Adenosine triphosphate, ATP. Usually a white crystalline subtance. The shape of adenine is ...
(A),
thymine Thymine () (symbol T or Thy) is one of the four nucleotide bases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The others are adenine, guanine, and cytosine. Thymine is also known as 5-methyluracil, a pyrimidine ...
(T),
guanine Guanine () (symbol G or Gua) is one of the four main nucleotide bases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine ( uracil in RNA). In DNA, guanine is paired with cytosine. The guanine nucleoside ...
(G),
cytosine Cytosine () (symbol C or Cyt) is one of the four nucleotide bases found in DNA and RNA, along with adenine, guanine, and thymine ( uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attac ...
(C) and
uracil Uracil () (nucleoside#List of nucleosides and corresponding nucleobases, symbol U or Ura) is one of the four nucleotide bases in the nucleic acid RNA. The others are adenine (A), cytosine (C), and guanine (G). In RNA, uracil binds to adenine via ...
(U) inside carbon-rich meteorites. These compounds are building blocks of
DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...
and
RNA Ribonucleic acid (RNA) is a polymeric molecule that is essential for most biological functions, either by performing the function itself (non-coding RNA) or by forming a template for the production of proteins (messenger RNA). RNA and deoxyrib ...
, the
genetic code Genetic code is a set of rules used by living cell (biology), cells to Translation (biology), translate information encoded within genetic material (DNA or RNA sequences of nucleotide triplets or codons) into proteins. Translation is accomplished ...
of all
life Life, also known as biota, refers to matter that has biological processes, such as Cell signaling, signaling and self-sustaining processes. It is defined descriptively by the capacity for homeostasis, Structure#Biological, organisation, met ...
on Earth. These compounds have also occurred spontaneously in laboratory settings emulating conditions in outer space."These meteorites contain all of the building blocks of DNA"
, LiveScience, 28 April 2022


Sources of meteorites found on Earth

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.


Weathering

Most meteorites date from the early Solar System and are by far the oldest extant material on Earth. Analysis of terrestrial
weathering Weathering is the deterioration of rocks, soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs '' in situ'' (on-site, with little or no move ...
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.P. A. Bland, M. E. Zolensky, G. K. Benedix, M. A. Sephton. '
Weathering of Chondritic Meteorites
"''
The most commonly employed weathering scale, used for ordinary chondrites, ranges from W0 (pristine state) to W6 (heavy alteration).


Fossil meteorites

"Fossil" meteorites are sometimes discovered by geologists. They represent 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 Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
quarry in Sweden has produced an anomalously large number – exceeding one hundred – fossil meteorites from the
Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...
, nearly all of which are highly weathered L-chondrites that still resemble 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 Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , a diminutive form of ''spine,'' in reference to its pointed crystals. Prop ...
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 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 object A near-Earth object (NEO) is any small Solar System body orbiting the Sun whose closest approach to the Sun ( perihelion) is less than 1.3 times the Earth–Sun distance (astronomical unit, AU). This definition applies to the object's orbit a ...
s.


Collection

A "meteorite fall", also called an "observed fall", 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. , the ''Meteoritical Bulletin Database'' had 1,180 confirmed falls.


Falls

Most meteorite falls are collected on the basis of eyewitness accounts of 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 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 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, 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 the orbit, magnitude, ground track, and other parameters over the southeast USA, which often detects a number of events each night.


Finds

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 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.


Canada

Meteorites that land in Canada are protected under the ''Cultural Property Export and Import Act''. In July 2024, a meteorite was recorded by security footage crashing into a residential property in Marshfield, Prince Edward Island. It is believed to be the first time such an event has been captured on camera and the sound of the crash recorded. It was subsequently registered as the Charlottetown meteorite, named after the city near to where it landed.


United States

Nininger's strategy was to search for meteorites in the
Great Plains The Great Plains is a broad expanse of plain, flatland in North America. The region stretches east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. They are the western part of the Interior Plains, which include th ...
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 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 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 In soil science, agriculture and gardening, hardpan or soil pan is a dense layer of soil, usually found below the uppermost topsoil layer. There are different types of hardpan, all sharing the general characteristic of being a distinct soil layer ...
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 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 Barstow is a city in San Bernardino County, California, in the Mojave Desert of Southern California. Located in the Inland Empire region of California, the population was 25,415 at the 2020 United States census, 2020 census. Barstow is an impor ...
, and the Franconia and Gold Basin meteorite strewn fields; hundreds of kilograms of meteorites have been recovered from each. A number of finds from 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 The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California, United States. Its academic roots were established in 1881 as a normal school then known as the southern branch of the C ...
's Meteorite Gallery.


Antarctica

A few meteorites were found in
Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...
between 1912 and 1964. In 1969, 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 sheet In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacier, glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are the Antarctic ice sheet and the Greenland ice sheet. Ice s ...
s 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, the United States began its own program to search for Antarctic meteorites, operating along the
Transantarctic Mountains The Transantarctic Mountains (abbreviated TAM) comprise a mountain range of uplifted rock (primarily sedimentary) in Antarctica which extends, with some interruptions, across the continent from Cape Adare in northern Victoria Land to Coats L ...
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) 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).


Australia

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 the hot deserts of Australia. Several dozen meteorites had already been found in the Nullarbor region of Western and
South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. With a total land area of , it is the fourth-largest of Australia's states and territories by area, which in ...
. 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 Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
. In the extremely arid climate, there has been relatively little
weathering Weathering is the deterioration of rocks, soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs '' in situ'' (on-site, with little or no move ...
or
sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to th ...
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.


The Sahara

In 1986–87, a German team installing a network of seismic stations while prospecting for oil discovered about 65 meteorites on a flat, desert plain about southeast of Dirj (Daraj),
Libya Libya, officially the State of Libya, is a country in the Maghreb region of North Africa. It borders the Mediterranean Sea to the north, Egypt to Egypt–Libya border, the east, Sudan to Libya–Sudan border, the southeast, Chad to Chad–L ...
. 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 the case of several meteorite fields, such as Dar al Gani, Dhofar, and others, favorable light-colored geology consisting of
basic Basic or BASIC may refer to: Science and technology * BASIC, a computer programming language * Basic (chemistry), having the properties of a base * Basic access authentication, in HTTP Entertainment * Basic (film), ''Basic'' (film), a 2003 film ...
rocks (clays, dolomites, and
limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
s) 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 scientific method is an empirical method for acquiring knowledge that has been referred to while doing science since at least the 17th century. Historically, it was developed through the centuries from the ancient and medieval world. The ...
. 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 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 the total number of well-described meteorites found in Algeria and Libya to more than 500.


Northwest Africa

Meteorite markets came into existence in the late 1990s, especially in
Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc ...
. 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 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 the more notable meteorites recovered include Tissint and NWA 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.


Arabian Peninsula

In 1999, meteorite hunters discovered that the desert in southern and central
Oman Oman, officially the Sultanate of Oman, is a country located on the southeastern coast of the Arabian Peninsula in West Asia and the Middle East. It shares land borders with Saudi Arabia, the United Arab Emirates, and Yemen. Oman’s coastline ...
were also favorable for the collection of many specimens. The gravel plains in 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 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 the US as well as several other European countries.


In human affairs

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.


Ceremonial or religious use

Although 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 The Temple of Artemis or Artemision (; ), also known as the Temple of Diana, was a Greek temple dedicated to an ancient, localised form of the goddess Artemis (equated with the Religion in ancient Rome, Roman goddess Diana (mythology), Diana) ...
at Ephesus, one of the Seven Wonders of the Ancient World, possibly originated with the observation and recovery of a meteorite that was understood by contemporaries to have fallen to the earth from
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 Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...
, 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 The Black Stone () is a rock set into the eastern corner of the Kaaba, the ancient building in the center of the Masjid al-Haram, Grand Mosque in Mecca, Saudi Arabia. It is revered by Muslims as an Islamic relic which, according to Muslim tradi ...
set into the wall of the
Kaaba The Kaaba (), also spelled Kaba, Kabah or Kabah, sometimes referred to as al-Kaba al-Musharrafa (), is a stone building at the center of Islam's most important mosque and Holiest sites in Islam, holiest site, the Masjid al-Haram in Mecca, Sa ...
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, a iron meteorite was found in a Sinagua (c. 1100–1200 AD) burial cyst near Camp Verde, Arizona, respectfully wrapped in a feather cloth.H. H. Nininger, 1972, ''Find a Falling Star'' (autobiography), New York, Paul S. Erikson. 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 Meteoric iron, sometimes meteoritic iron, is a native metal and early-universe protoplanetary-disk remnant found in meteorites and made from the elements iron and nickel, mainly in the form of the mineral phases kamacite and taenite. Meteoric ...
found in Hopewell burial mounds, and the discovery of the Winona meteorite in a Native American stone-walled crypt.


Historical writings

In medieval China during the
Song dynasty The Song dynasty ( ) was an Dynasties of China, imperial dynasty of China that ruled from 960 to 1279. The dynasty was founded by Emperor Taizu of Song, who usurped the throne of the Later Zhou dynasty and went on to conquer the rest of the Fiv ...
, a meteorite strike event was recorded by
Shen Kuo Shen Kuo (; 1031–1095) or Shen Gua, courtesy name Cunzhong (存中) and Art name#China, pseudonym Mengqi (now usually given as Mengxi) Weng (夢溪翁),Yao (2003), 544. was a Chinese polymath, scientist, and statesman of the Song dynasty (960� ...
in 1064 AD near
Changzhou Changzhou is a prefecture-level city in southern Jiangsu, China. It was previously known as Yanling, Lanling, and Jinling. Located on the southern bank of the Yangtze River, Changzhou borders the provincial capital of Nanjing to the west, Zhen ...
. 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 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 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 Jean-Baptiste Biot (; ; 21 April 1774 – 3 February 1862) was a French people, French physicist, astronomer, and mathematician who co-discovered the Biot–Savart law of magnetostatics with Félix Savart, established the reality of meteorites, ma ...
and the British chemist, Edward Howard. Biot's study, initiated by the
French Academy of Sciences The French Academy of Sciences (, ) is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French Scientific method, scientific research. It was at the forefron ...
, was compelled by a fall of thousands of meteorites on 26 April 1803 from the skies of L'Aigle, France.


Striking people or property

Throughout history, many first- and second-hand reports speak of meteorites killing humans and other animals. One example is from 1490 AD in China, which purportedly killed thousands of people. John Lewis has compiled some of these reports, and summarizes, "No one in recorded history has ever been killed by a meteorite in the presence of a meteoriticist and a medical doctor" and "reviewers who make sweeping negative conclusions usually do not cite any of the primary publications in which the eyewitnesses describe their experiences, and give no evidence of having read them". Modern reports of meteorite strikes include: *In 1954 in Sylacauga, Alabama. A stone chondrite, the Hodges meteorite or Sylacauga meteorite, crashed through a roof and injured an occupant. *An approximately fragment of the Mbale meteorite fall from
Uganda Uganda, officially the Republic of Uganda, is a landlocked country in East Africa. It is bordered to the east by Kenya, to the north by South Sudan, to the west by the Democratic Republic of the Congo, to the south-west by Rwanda, and to the ...
struck a youth, causing no injury. *In October 2021 a meteorite penetrated the roof of a house in
Golden, British Columbia Golden is a town in southeastern British Columbia, Canada, west of Calgary, Alberta, and east of Vancouver. History In 1807, David Thompsonrenowned fur trader, surveyor, and map makerwas tasked by the North West Company to open a trading rou ...
landing on an occupant's bed.


Notable examples


Naming

Meteorites are always named for the places they were found, where practical, usually a nearby town or geographic feature. In cases where many meteorites were found in one place, the name may be followed by a number or letter (e.g., Allan Hills 84001 or Dimmitt (b)). The name designated by the Meteoritical Society is used by scientists, catalogers, and most collectors.


Terrestrial

* Allende – largest known carbonaceous chondrite ( Chihuahua, Mexico, 1969). * Allan Hills A81005 – First meteorite determined to be of lunar origin. * Allan Hills 84001Mars meteorite that was claimed to prove the existence of life on
Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...
. * The Bacubirito Meteorite (Meteorito de Bacubirito) – A meteorite estimated to weigh . * Campo del Cielo – a group of iron meteorites associated with a crater field (of the same name) of at least 26 craters in West
Chaco Province Chaco (; Wichi languages, Wichi: ''To-kós-wet''), officially the Province of Chaco ( ) is one of the 23 provinces of Argentina, provinces of Argentina. Its capital and largest city is Resistencia, Chaco, Resistencia. It is located in the north- ...
, Argentina. The total weight of meteorites recovered exceeds 100 tonnes. * Canyon Diablo – Associated with Meteor Crater in Arizona. * Cape York – One of the largest meteorites in the world. A 34-ton fragment called "Ahnighito", is exhibited at the
American Museum of Natural History The American Museum of Natural History (AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. Located in Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 21 interconn ...
; the largest meteorite on exhibit in any museum. * Gibeon – A large Iron meteorite in
Namibia Namibia, officially the Republic of Namibia, is a country on the west coast of Southern Africa. Its borders include the Atlantic Ocean to the west, Angola and Zambia to the north, Botswana to the east and South Africa to the south; in the no ...
, created the largest known strewn field. * Hoba – The largest known intact meteorite. * Kaidun – An unusual carbonaceous chondrite. * Mbosi meteorite – A 16-metric-ton ungrouped iron meteorite in Tanzania. * Murchison – A carbonaceous chondrite found to contain
nucleobase Nucleotide bases (also nucleobases, nitrogenous bases) are nitrogen-containing biological compounds that form nucleosides, which, in turn, are components of nucleotides, with all of these monomers constituting the basic building blocks of nuc ...
s – the building block of life. * Nōgata – The oldest meteorite whose fall can be dated precisely (to 19 May 861, at Nōgata) * Orgueil – A famous meteorite due to its especially primitive nature and high presolar grain content. * Sikhote-Alin – Massive iron meteorite
impact event An impact event is a collision between astronomical objects causing measurable effects. Impact events have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or meteoroids and have minimal effe ...
that occurred on 12 February 1947. * Tucson Ring – Ring shaped meteorite, used by a blacksmith as an anvil, in Tucson AZ. Currently at the Smithsonian. * Willamette – The largest meteorite ever found in the United States. * 2007 Carancas impact event – On 15 September 2007, a stony meteorite that may have weighed as much as 4000 kilograms created a crater 13 meters in diameter near the village of Carancas,
Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
. * 2013 Russian meteor event – a 17-metre diameter, 10 000 ton asteroid hit the atmosphere above Chelyabinsk, Russia at 18 km/s around 09:20 local time (03:20 UTC) 15 February 2013, producing a very bright fireball in the morning sky. A number of small meteorite fragments have since been found nearby.


Extraterrestrial

* Bench Crater meteorite ( Apollo 12, 1969) and the Hadley Rille meteorite (Apollo 15, 1971) − Fragments of asteroids were found among the samples collected on the Moon. *Block Island meteorite and Heat Shield Rock – Discovered on
Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...
by Opportunity rover among four other iron meteorites. Two nickel-iron meteorites were identified by the Spirit rover. (See also: List of rocks on Mars)


Large impact craters

* Acraman crater in South Australia ( diameter) * Ames crater in Major County, Oklahoma diameter * Brent crater in northern Ontario ( diameter) * Chesapeake Bay impact crater ( diameter) * Chicxulub crater off the coast of Yucatán Peninsula ( diameter) * Clearwater Lakes a double crater impact in Québec, Canada ( in diameter) * Lonar crater in India ( diameter) * Lumparn in Åland, in the Baltic Sea ( diameter) * Manicouagan Reservoir in Québec, Canada ( diameter) * Manson crater in Iowa ( crater is buried) * Meteor Crater in Arizona, also known as "Barringer Crater", the first confirmed terrestrial impact crater. ( diameter) * Mjølnir impact crater in the Barents Sea ( diameter) * Nördlinger Ries crater in Bavaria, Germany ( diameter) * Popigai impact structure in Russia ( diameter) * Siljan Ring in Sweden, largest crater in Europe ( diameter) * Sudbury Basin in Ontario, Canada ( diameter). * Ungava Bay in Québec, Canada () * Vredefort impact structure in South Africa, the largest known impact structure on Earth ( diameter from an estimated wide meteorite).


Disintegrating meteoroids

*
Tunguska event The Tunguska event was a large explosion of between 3 and 50 TNT equivalent, megatons that occurred near the Podkamennaya Tunguska River in Yeniseysk Governorate (now Krasnoyarsk Krai), Russia, on the morning of 30 June 1908. The explosion over ...
in Siberia 1908 (no crater) * 2013 Russian meteor event, Chelyabinsk event in Russia 2013 (no known crater)


See also

* Atmospheric focusing *Barringer Medal * Glossary of meteoritics * List of impact craters on Earth * List of Martian meteorites * List of meteorite minerals * List of rocks on Mars * List of possible impact structures on Earth * List of individual rocks * Meteor shower * Meteorite find * Meteoroid * Micrometeorite * Panspermia


References


External links


Current meteorite news articles

The British and Irish Meteorite Society

The Natural History Museum's meteorite catalogue database

Meteoritical Society

Earth Impact Database

Every Recorded Meteorite Impact on Earth
from Tableau Software
Meteor Impact Craters Around the World

Identifying meteorites
from the Washington University in St. Louis * {{Authority control Meteorites, Geophysics Solar System