A meteorite [ meteoˈrit ] is a relatively small solid of cosmic origin that has crossed the earth's atmosphere and reached the ground. It usually consists mainly of silicate minerals or an iron - nickel alloy, a certain part of which burned up when it entered the earth's atmosphere. Since they are almost always multi-grain mineral aggregates , meteorites are counted among the rocks regardless of their chemical composition .
The place of formation of the meteorites is the solar system . They enable valuable insights into its early days.
The original body is called meteoroids as long as it is still in interplanetary space . When entering the earth's atmosphere, it creates a luminous phenomenon known as a meteor . The meteoroid either burns up as a shooting star in the earth's atmosphere or reaches the ground as a meteorite.
Meteoroids, which originate from the solar system, have a maximum heliocentric speed of about 42 km / s in the area of the earth orbit (see third cosmic speed ). Since the orbital speed of the earth is around 30 km / s, relative speeds of a maximum of 72 km / s or 260,000 km / h are possible.
When entering the earth's atmosphere, the meteoroids are slowed down very strongly. In doing so, they are heated, causing them to partially melt or evaporate on the surface. Since the fall through the earth's atmosphere only lasts a few seconds, the interior, especially of larger meteorites, cannot heat up significantly. Only after the impact can the frictional heat generated on the surface be released into the interior of the meteorite through thermal conduction . However, since the volume of the heated surface is usually small in relation to the total volume, the interior remains relatively cool and unchanged.
The word meteorite is derived from the ancient Greek μετέωρος metéōros with the meaning “lifted up”, “high in the air” (compare meteorology ). Mainly until the middle of the 20th century, meteorites were mainly called meteor stones , before that the names aerolite ("air stone") and uranolite ("sky stone ") were common. Until the beginning of the 1990s, the objects known today as meteoroids - as well as the remains of these objects that came to the surface of the earth - were listed as meteorites.
Classification and naming
According to their internal structure, meteorites are divided into undifferentiated and differentiated meteorites:
- undifferentiated meteorites contain the first and therefore oldest heavy chemical elements that were formed in the solar system by nuclear fusion. They are by far the most common meteorites found and are called chondrites ; they are counted among the stone meteorites .
- on the other hand, the differentiated meteorites mainly come from asteroids , some also from Mars or the Earth's moon, that is, celestial bodies that, like the earth, have a shell-like structure through melting processes; this material separation is called differentiation . Differentiated meteorites can be further subdivided into
- the non-chondritic stone meteorites, also called achondrites ; they come from the mantle of the asteroids.
- consisting of an iron - nickel - alloy existing iron meteorites , they are derived from the core of asteroids.
- the stone-iron meteorites , they come from the transition area between core and mantle.
Depending on whether the fall of a meteorite has been observed or whether the meteorite has already fallen unobserved and was only found, a meteorite is classified as a "fall" or a "find". In addition to the chemical and petrological classification, meteorite finds are also divided into weathering classes according to the degree of weathering since they hit the earth's surface. NASA uses classes A, B and C, depending on the strength of the brown discoloration from iron oxides visible on the fracture surfaces. An alternative classification system determines the degree of conversion of troilite and metal into oxides (W0 to W4) and the conversion of silicates into clay minerals (W5 and W6). These W-classes can only be used meaningfully on meteorites with troilite and metal grains, i.e. H. Chondrites. Meteorites can have metamorphosis due to a shock event, for example while knocking loose from the mother's body. This is described by dividing it into shock classes S1-S6, where S1 shows meteorites that are not or only very weakly shocked and S6 the most severely shocked meteorites.
In individual cases, the decision as to whether a piece of rock found is actually a meteorite can only be made by a specialist. In the case of metallic meteorites, for example, he uses the Widmanstätten figures. They become visible when you cut open an iron meteorite, polish the cut surfaces and etch them with an acid , for example dilute nitric acid. The characteristic crystal structures of the metal then appear , precisely the Widmanstätten figures that only appear in meteorites. They are formed in the mother body of the iron meteorites during a very slow cooling over millions of years. There are, however, iron meteorites that do not show any Widmanstätten figures; their absence does not exclude a meteorite.
Another way to identify a found piece of iron as a meteorite is a nickel test , since all iron meteorites contain at least 4 percent nickel . An indication of a stone meteorite can be the presence of a black enamel crust and small spheres (chondrules). A found piece of stone can be tested for magnetism with a magnet, since chondrites are magnetic because of the small metallic iron particles they contain. Pseudometeorites are those finds that were initially mistaken for a meteorite due to more or less great similarities to meteoritic rock, but which on closer analysis turned out to be earthly rock.
A distinction is made between three different ages for meteorites: the age of formation, the age of irradiation and the terrestrial age.
The exact rules of naming were drawn up by the Meteoritical Society , an international specialist society. The journal of the Meteoritical Society is the journal Meteoritics & Planetary Science, or MAPS for short. The Meteoritical Bulletin appears here with catalogs, inventories and routine descriptions of new meteorites. This supplement with the lists of all submitted and classified new finds and cases checked and approved by the Nomenclature Committee is the standard reference work for the inventory and the nomenclature of all meteorites.
Accordingly, meteorites are named after their place of discovery (place, river, etc.). In places where a lot of meteorites are found, such as some areas in the Sahara , a sequential number is appended (for example DaG 262 from D ar a l- G ani ). In the case of meteorites found in Antarctica , the year and a serial number are appended to the abbreviation. For example, ALH 76008 denotes the eighth meteorite that was collected in 1976 in the Allan Hills area in Antarctica. The Martian meteorite ALH 84001 , made famous by the apparent traces of fossil bacteria, was therefore the first meteorite found in this area in 1984.
Most meteorites are fragments of asteroids and come from the asteroid belt between Mars and Jupiter . They were knocked loose from their mother body by collisions. The typical Widmanstätten figures in iron-nickel meteorites, for example, can only arise when a molten metallic body cools down very slowly, over millions of years. Such cooling times are only achieved in the core of celestial bodies, such as in asteroids.
The period of time between the separation from the mother body and the impact on the earth is typically a few million years, but can also be more than a hundred million years. Meteorites contain the oldest material in our solar system, which was formed along with it 4.56 billion years ago. They offer the only direct terrestrial access to research into the formation of the solar system. Similar old material is found not only in asteroids but also in comets and can only be examined more closely with the help of space probes .
It has now been proven that some meteorites come from the moon ( lunar meteorites ) and from Mars ( Martian meteorites ). They too must have been knocked out of these celestial bodies by the impact of a small body and hurled into space. For the carbonaceous chondrite Kaidun the Martian moon Phobos and for the enstatite Abee and the achondrite NWA 7325 even Mercury was suggested as the original body, which is, however, controversial. The Diogenites , Eukrites and Howardites are assigned to the asteroid Vesta . So far, no meteorites have been found that can be proven to originate from comets or even from interstellar space, although a cometary origin is discussed for some of the micrometeorites and most meteor streams are associated with comets. Here, too, the majority presumably come mainly from asteroids.
Frequency of meteorite falls
Several meteorite falls are observed on Earth every year. All cases of which material has been found and analyzed are recorded and published in the Meteoritical Bulletin . An evaluation of this data (as of December 31, 2019) results in case rates of 1 to 17 cases per year. The following figures result over a period of 10 years:
- 1900 to 1909: 56 cases, or an average of 5.6 cases per year
- 1910 to 1919: 66 cases, or an average of 6.6 cases per year
- 1920 to 1929: 70 cases, or an average of 7.0 cases per year
- 1930 to 1939: 92 cases, or an average of 9.2 cases per year
- 1940 to 1949: 57 cases, or an average of 5.7 cases per year
- 1950 to 1959: 60 cases, or an average of 6.0 cases per year
- 1960 to 1969: 63 cases, or an average of 6.3 cases per year
- 1970 to 1979: 61 cases, or an average of 6.1 cases per year
- 1980 to 1989: 56 cases, or an average of 5.6 cases per year
- 1990 to 1999: 59 cases, or an average of 5.9 cases per year
- 2000 to 2009: 68 cases, or an average of 6.8 cases per year
- 2010 to 2019: 78 cases, or an average of 7.8 cases per year
The number of observed meteorite falls was therefore in the 20th / 21st. Century at an average of 6.6 per year.
The actual fall rate is much higher, however: a large part falls into the sea or on unpopulated areas. But even in more densely populated areas such as Central Europe, many cases will escape observation. When the stone meteorite Ramsdorf fell on July 26, 1958, for example, no light was seen, only a crackling sound was heard near the point of impact. If the meteorite had fallen a few kilometers away from a town, probably nobody would have noticed it. NASA scientists speak of a "river of extraterrestrial material" sinking to earth, which amounts to 100 tons per day.
An estimate of the actual fall rate is possible from photographically recorded meteor trajectories. From 1974 to 1983, a camera network in Canada evaluated meteoric trajectories over an area of 1.26 million square kilometers that must have delivered meteorites, and obtained the following figures for cases over 0.1 kg per year:
- Total area of the earth: 19,000 cases
- Land area of the earth: 5800 cases
- per 1 million km²: 39 cases
This would result in a case rate of around 14 cases per year for the 0.36 million km² of Germany.
Meteorites fall evenly all over the world, but there are places where they are more common than others. While they weather very quickly in temperate climates , mainly due to the oxidation of the metallic iron, which is not stable on the earth's surface , they can last tens of thousands of years in arid regions such as the North African deserts, and sometimes even over a million years in the Antarctic . It is also helpful that meteorites are easily noticeable because of their typically black melting crust. In the Antarctic there are also areas in which meteorites are collected by glaciers in so-called blue ice fields (“ meteorite traps ”). Expeditions are therefore often undertaken there to find new meteorites. The first object was found in Antarctica in 1912, the Adelie Land meteorite.
Meteorite finds in hot deserts
It is a relatively new finding that it is not only in the cold deserts at the South Pole, but also in hot deserts in certain areas that a concentration of meteorites can occur over long periods of time. After a team of German seismologists accidentally found around 65 meteorites in a comparatively small area during oil prospecting work in Libya in the Daraj area ( Nalut district ), a systematic search began in the Sahara. Since 1990 the number of finds made in the course of private and institutional meteorite expeditions, first in the Sahara and later also in the deserts of Oman, has grown steadily. Whereas in 1985 only 30 meteorite finds were known from Libya, Algeria , Morocco , the Republic of Niger and Oman, today there are more than 3,000. In addition, there is an unknown number of finds by locals who, without information on the circumstances of the find, mostly via the Moroccan markets was traded.
The best-known areas of discovery in the Sahara include the Hammada al-Hamra , Dar al-Gani in Libya , the Acfer area in Algeria , the Hammadah du Draa and the Tanezrouft desert, and Grein and the Ténéré Tafassasset in the Republic of Niger. The most important concentration areas in Oman are Dhofar, Jiddat Al Harasis and Say Al Uhaymir. The peak of discovery activity was exceeded in 2002 and the number of finds is now falling sharply. On the one hand, this is due to tightened export conditions in some desert states, but it is also an indication that the known find areas are largely exploited.
The find areas in hot deserts are aggregation areas on which the soils have preserved meteorite falls for tens of thousands of years under very specific conditions. Similar to the concentration process in the Antarctic, this happens initially through sedimentation of the newly added cases. Protected from the effects of the weather by new sediment layers even in more humid climates, the meteorites survived in the soil layers for up to several tens of thousands of years. In the Sahara, wind erosion finally exposed the meteorites that were preserved in this way during the most recent climatic phase, which has been becoming increasingly dry for around 3000 years. The covering layers of soil were removed in the affected areas by the northeast wind blowing almost all year round over the Sahara.
The lack of quartz sand in the corresponding areas is also decisive for the concentration process of meteorites. The comparatively hard quartz sands lead to faster destruction of the meteorites by wind grinding . The dense meteorite concentrations in the Sahara are therefore usually on plateaus above the sand flight or in the lee of mountain ranges.
In order to be able to find the meteorites in their aggregation areas, special topographical and geological conditions are required. Light-colored surfaces with a slightly basic pH value have proven to be the best for prospecting. On the other hand, terrain contaminated by dark river pebbles or volcanic depths or ejecta rocks is unsuitable for prospecting. On such horizons, meteorites cannot be distinguished from the surrounding rock. It is just as important that the hydraulic gradient of the surface is as low as possible, since the mechanical and chemical weathering of the meteorites is also accelerated on inclined surfaces. Under ideal conditions, a meteorite can be found in a dense concentration area on every 10 to 12 square kilometers.
The almost complete absence of iron meteorites from the find areas in the hot deserts has not yet been clarified. Iron meteorites , with a share of around 0.2% in the African desert finds, represent a significantly smaller proportion than one would assume with a view to their percentage of the observed cases (approx. 4%). One possible reason for this is the targeted collection and processing of meteors in the find areas by the prehistoric inhabitants of the Sahara.
Reports of stones falling from the sky have been around since the earliest times. For example, the Greek writer Plutarch reports on a black stone that was found around 470 BC. Is said to have fallen in Phrygia . This meteorite was worshiped in the name of the goddess Cybele until it became known after the Romans (who called them Mater Deum Magna Ideae ) took over the Cybele cult in 204 BC. BC was brought in a great procession to Rome , where he was venerated for centuries. Around 465 BCE , Diogenes of Apollonia interpreted the fall of a meteorite on the Gallipoli peninsula as "the fall of an extinct star".
Meteorites were already the subject of religious cults in prehistoric times, as is shown by finds in tombs of the Sinagua culture . The Winona meteorite was found in a stone container in a prehistoric pueblo in Arizona in 1928, where it apparently served cultic purposes. The black stone Hajar al-Aswad , which is walled into the Kaaba , the central sanctuary of Islam , may also be a meteorite, although this has not been scientifically proven.
The Chinese historian Ma Duanlin (1245–1325) reports on meteorite falls over a period of 2000 years. An evaluation of early Chinese records by the meteorite researchers K. Yau, P. Weissman and D. Yeomans revealed 337 observed meteorite falls between 700 BC. And 1920. The Nogata meteorite , which fell in AD 861, is the earliest observed fall of which material is still preserved today.
The first recorded meteorite in Europe, of which material is still available, fell in 1400 AD in Elbogen in Bohemia , the exact date and the circumstances of the fall are not known. The fall of Ensisheim in Alsace caused a sensation when, in 1492, a stone meteorite fell from the sky with a great roar. Numerous chronicles and leaflets reported on the event. The oldest remains of meteorites found on earth are "fossil meteorites", which have undergone an exchange of substances with the rock in which they are embedded and whose meteoritic origin can only be recognized by their structure. For example, embedded fragments of fossil chondritic meteorites have been found in limestone layers in Sweden, which fell to earth in the Ordovician about 450-480 million years ago.
An observation on June 30, 1908 ( Tunguska event ) is regarded as a spectacular recent event . Witnesses observed a pale blue fireball in the sky over the Siberian Tunguska region . Shortly afterwards, the pressure wave of an explosion leveled around 2,000 square kilometers of forest to the ground, which corresponds to a circular area of 50 kilometers in diameter. The air pressure fluctuations caused by the explosion could still be registered in London. Among other theories, it is believed that this event was the explosion of a meteoroid, presumably a comet nucleus fragment or a smaller asteroid, about 50 to 100 meters in diameter at an altitude of about 10,000 meters. Meteorites or a crater that could have been formed by the event have not yet been found in the corresponding area, but a few hours after the event, the Kagarlyk meteorite fell near Kiev . So far it has not been clarified whether this is a coincidental clash of the two events or whether there is a connection.
Meteoritic iron was used for the manufacture of cult objects, tools and weapons even before the actual Iron Age . For example, in a small burial ground from the time between 3500 and 3000 BC. Found iron pearls with a nickel content of 7.5 percent near the Egyptian settlement of Gerzeh , which suggests the meteoritic origin. A dagger blade was also found in the burial chamber of Pharaoh Tutankhamun , which is believed to have possibly been made from meteoritic iron. Two analyzes of the dagger blade published in 2016 give strong support to the assumption of a meteoritic origin of the blade material. Even today, the so-called meteorite iron is used as jewelry or as part of handmade knives because of its relative rarity. If you etch meteorite iron with acid, a pattern emerges because the different metals are attacked to different degrees by the acid. This Widmanstätten structure is also called meteorite damascus .
History of meteorite research
Scientific research into meteorites began at the end of the 18th century. The first publication on the chemical analysis of a stone that fell near Lucé in France in 1768 using modern chemical methods was published in 1777 by the chemists Fourgeroux, Chadet and Lavoisier in the Journal de Physique . However, the authors came to the wrong conclusion that the stone was of earthly origin and possibly formed by lightning strikes in sandstone.
The publication of the physicist Ernst FF Chladni on the origin of the iron masses found by Pallas and others similar to them is considered a milestone in the acceptance of meteorites as extraterrestrial objects . In this essay, published in 1794, Chladni discusses historical reports on meteors and fireballs and explains why many of the very different explanations of the origin of these phenomena that existed at the time cannot be correct. Furthermore, he hypothesizes that these phenomena are linked to reports of stone and iron masses that have fallen from the sky. He also suggests that these bodies came from space. This work was triggered by discussions with the physicist and philosopher Georg Christoph Lichtenberg , who himself had observed a fireball in 1791.
Reports of stones or masses of iron falling from the sky were mostly dismissed by scientists as superstitions before Chladni was published. If anything, at most an atmospheric origin of meteorites was accepted, which was also a common explanation for meteors and fireballs. In particular, claims that meteorites are of extraterrestrial origin have often been answered by enlightened and educated people with ridicule and polemics. One reason for this was the belief, which goes back to Aristotle and was confirmed by Isaac Newton , that the solar system, apart from the larger bodies such as planets, moons and comets, is free of matter and at most is filled with a substance called ether . The first meteorite collections were founded as early as the 18th century, before the knowledge that meteorites were of extraterrestrial origin. The oldest meteorite collection in the world is in the Natural History Museum in Vienna , where the foundation stone was laid with the Hraschina meteorite (fell in 1751); Today there is the largest exhibition collection in the world with approx. 1100 objects.
Chladni's theses were initially rejected by most scientists, but they received increasing support from other observed cases ( e.g. Wold Cottage 1795, L'Aigle 1803) and research reports. William Thomson provided the first mineralogical description of a stone that fell near Siena in Italy in 1794 , in which he showed that it is different from all known earthly rocks. Edward C. Howard and Jacques-Louis de Bournon analyzed four meteorites for their chemical composition in 1802. De Bournon first mentioned the silicate spheres found in these, which Gustav Rose named chondrons in 1869 .
While in the first half of the 19th century the lunar craters or accumulations of dust in the high atmosphere, which were wrongly interpreted as lunar volcanoes, were discussed as the origin of most meteorites, the asteroid belt or even an interstellar origin was later assumed. The fact that almost all meteorites are fragments from the asteroid belt became apparent around 1940 through photographic recordings of some meteors by FL Whipple and CC Wylie, from which elliptical orbits could be inferred. With an interstellar origin, hyperbolic orbits would have been expected. In 1959, the orbit of the meteorite Přibram could be recorded by several cameras and the orbit calculated, the aphelion of which was in the asteroid belt. However, at the beginning of the 1980s, with the help of the latest cosmochemical data, it was also possible to prove that around every thousandth meteorite came from the moon and a comparable number even from Mars. It is estimated that around 45,000 meteorites are stored in private and scientific-institutional collections around the world.
Current meteorite research
In addition to samples of lunar rocks from the Apollo and Luna missions, as well as the particles captured from the solar wind ( Mission Genesis ), comet Wild 2 and interstellar dust ( Mission Stardust ), meteorites represent the only extraterrestrial material that is examined in earthly laboratories can. That is why research on meteorites is very important for planetology and cosmochemical issues. Using isotope measurements on presolar minerals, models of nucleosynthesis in supernovae and the vicinity of red giants can be checked. Meteorites are also very important for research into the formation of our planetary system . For calcium-aluminum-rich inclusions in primitive chondrites, an age between 4.667 and 4.671 billion years could be proven with various dating methods. Because these are probably the oldest minerals formed in the solar system, they mark the beginning of the formation of our planetary system. The dating of the different classes of meteorites allows an increasingly more accurate chronological representation of the individual processes in the early solar system. Numerous minerals such as niningerite have also been discovered in meteorites , which have not yet been found on earth.
Meteorite impacts have also strongly influenced the history of the earth, which is why they are of interest for this reason. After its formation and until about 3.9 billion years ago, the earth was exposed to heavy bombardment by extraterrestrial objects for a few hundred million years . The meteorite impact known as the KT impact 65 million years ago, which is responsible for the extinction of the dinosaurs , is now widely known . The earth's age of 4.55 billion years, which is generally accepted today, was first determined in 1953 by CC Patterson using uranium-lead dating on the Canyon-Diablo meteorite .
Starting with the discovery of organic compounds in the carbonaceous chondrite of Murchison , meteorites are playing an increasingly important role in astrobiology and the study of the origin of life. In addition to amino acids and polycyclic aromatic hydrocarbons , which have now also been detected in other carbonaceous chondrites, fullerenes and even diamino acids have been detected in Murchison . It is believed that diamino acids played an important role in the first prebiotic reactions that ultimately led to RNA and DNA . This discovery is an indication that some important building blocks of life could have reached earth through meteorites. An even more sensational research result in this area was the discovery of allegedly fossil traces of bacterial life in the Martian meteorite ALH 84001 , which is still controversially discussed today .
In 2012, a figure about 24 cm tall and weighing about 10 kg was examined, which is said to have been discovered by a German Tibet expedition in the 1930s and which was kept in a private collection until 2009. Researchers assume that the figure was made from a fragment of the Chinga iron meteorite that fell around 15,000 years ago in what is now Mongolia or Siberia.
Fall and impact
A distinction is made between individual cases and multiple cases. In a single case, a meteoroid reaches the surface of the earth without breaking into several parts due to the forces acting during atmospheric flight. The individual cases are often iron meteorites, more rarely stone iron meteorites or stone meteorites. This can be attributed to the higher density and the more compact structure of the iron meteorites. It counteracts the torsional, tensile and compressive forces that act due to the accumulation of air and the high speeds when entering the earth's atmosphere.
Multiple cases occur when the earth's atmosphere comes into contact with meteoroids of a meteor shower and also when a single meteoroid breaks up into several fragments during the flight of the atmosphere. Shock events, caused by collisions of the mother bodies of the meteorites in the asteroid belt, lead to fractures and hairline cracks in the broken fragments, especially in the case of silicate bodies. When entering the earth's atmosphere, these asteroid debris often break apart along these fractures. This process can take place successively in several stages, which means that the meteoroid finally reaches the lower layers of the atmosphere in the form of a swarm of rubble (e.g. Pultusk 1868, Hoolbrook 1912, Sikhote-Alin 1947, Gao-Guenie 1960, Thuathe 2002 , Bassikounou 2006, Tamdakht 2008). However, in some cases final detonations are documented at the end point of the trajectory, only a few kilometers above the earth's surface (e.g. Tatahouine 1931).
The meteorites of multiple falls do not hit one point on the earth's surface together, but rather form an extensive stray field due to the different mass distribution in the swarm of rubble . Because of their inherent greater kinetic energy, the larger masses cover a more stretched, longer trajectory, while smaller masses are slowed down faster in their flight and more easily deflected by air resistance and wind drift. This behavior always results in an ellipse on the ground, within which the individual masses impact. This elliptical stray field is called a distribution ellipse. The largest masses are always at the end point of the ellipse, the smallest masses mark the starting point of the ellipse, they are also the first to reach the surface. Famous examples of classic distribution ellipses are the meteorite falls by Pultusk 1868, Hessle 1869, L'Aigle 1803, Dar Al Ghani 749 1999 (Fund), Thuathe 2002 and Bassikounou 2006.
Smaller meteorites are slowed down as they fly through the earth's atmosphere and finally fall in free fall during the so-called dark flight phase . When they hit the earth, they cause little, if any, damage. Nevertheless, around 100 cases are known in which meteorite impacts have led to (mostly minor) property damage, such as the Peekskill meteorite, a 12 kilogram chondrite that damaged a Chevrolet Malibu parked in New York State on October 9, 1992 Has.
To date, only one case is known in which a person was verifiably directly injured by a meteorite: On November 30, 1954, the 5.56 kg meteorite from Sylacauga in the US state of Alabama hit the roof of a house and hit it from the impact Already braked on a radio, the housewife Ann Elizabeth Hodges lying on a couch on the arm and hip, which resulted in extensive bruises. According to Alexander von Humboldt , a Franciscan was killed in an aerolite fall in Italy in 1660 .
However, a meteorite fall can also indirectly lead to considerable personal injury and material damage, as the meteor that fell in Chelyabinsk in 2013 shows: the detonation of the meteoroid in the upper atmosphere and the resulting atmospheric pressure wave caused the roof of a zinc factory to collapse. About 3,000 other buildings were damaged, mostly windows splitting and doors being pushed open. Hundreds of people received medical treatment for cuts (caused by shattered glass) and bruises.
Should a large meteorite fall in populated areas, it could result in considerable material damage and loss of life. Meteorites with a mass of over 100 tons are no longer significantly slowed down by the atmosphere, which is why their kinetic energy is released explosively when they hit the earth's surface , which leads to the formation of impact craters . Such impacts can cause a global natural disaster and - as in the case of the KT impact - lead to the mass extinction of numerous plant and animal species.
Calculation of the drop location of meteorites
The trajectory of a meteor through the earth's atmosphere can be determined by a geometric intersection process if the light trail in the starry sky has been recorded by the cameras of several meteor stations . The approximate location of the fall can be calculated from the direction and curvature of the flight path and the air density , which has led to several meteorites being found in Central Europe in recent years.
- List of meteorites
- List of meteorites in Germany
- List of meteorites in Austria
- List of meteorites in Switzerland
- Penetration force of meteorites, projectiles and other Newtonian impactors
- Meteor dust
Introductory specialist books and articles
- Ludolf Schultz: Planetology, an introduction. Birkhäuser-Verlag, Basel 1993, ISBN 3-7643-2294-2 .
- Ludolf Schultz, Jochen Schlueter: Meteorites . Primus Verlag, Darmstadt 2012, ISBN 978-3-86312-012-2 .
- Fritz Heide , F. Wlotzka: Small meteorite science. 3. Edition. Springer-Verlag, Berlin 1988, ISBN 3-540-19140-2 .
- RW Bühler: Meteorites. Primordial matter from interplanetary space. Birkhäuser-Verlag, Basel 1988, ISBN 3-7643-1876-7 .
- N. Widauer (Ed.): Meteorites - what falls on us from the outside. Texts and images at the intersection of science, art and literature. Verlag Niggli , Sulgen / Zurich 2005, ISBN 3-7212-0534-0 .
- OR Norton: The Cambridge Encyclopedia of Meteorites. Cambridge University Press, Cambridge 2002, ISBN 0-521-62143-7 .
- HY McSween, Jr .: Meteorites and Their Parent Planets. Cambridge University Press, Cambridge 1999, ISBN 0-521-58751-4 .
- UB Marvin: Ernst Florenz Friedrich Chladni (1756-1827) and the origins of modern meteorite research. In: Meteoritics & Planetary Science. Allen Press, Lawrence Kan 31.1996, pp. 545-588.
- R. Vaas: Death came from space. Meteorite impacts, earth orbit cruisers and the demise of the dinosaurs . Franckh-Kosmos, Stuttgart 1995, ISBN 3-440-07005-0 .
- A. von Humboldt: Kosmos. P. 60, footnote 69.
- D. de Niem: High-speed impacts from asteroids, comets and meteorites . Dissertation. TU Braunschweig, 2005.
- Mario Trieloff, Birger Schmitz, Ekaterina Korochantseva: Cosmic catastrophe in the ancient world. In: Stars and Space. 46 (6), 2007, pp. 28-35,
- Isidore Adler: The analysis of extraterrestrial materials. Wiley, New York 1986, ISBN 0-471-87880-4 .
- Iain Gilmour, Christian Köberl : Impacts and the early earth. Springer, Berlin 2000, ISBN 3-540-67092-0 .
- O. Richard Norton, Lawrence A. Chitwood: Field guide to meteors and meteorites. Springer, London 2008, ISBN 978-1-84800-156-5 .
- Virgiliu Pop: Property status of extraterrestrial samples and extracted resources. In: V. Pop: Who owns the moon? Extraterrestrial aspects of land and mineral resources ownership. Springer, Berlin 2008, ISBN 978-1-4020-9134-6 , pp. 135-151.
- Svend Buhl, Don McColl: Henbury Craters & Meteorites. Their Discovery, History and Study . Edited by S. Buhl. Meteorite Recon, Hamburg 2012, ISBN 978-3-00-039026-5 .
- F. Brandstätter, L. Ferrière, C. Köberl: Meteorites - Contemporary witnesses of the origin of the solar system / Meteorites - Witnesses of the origin of the solar system. Verlag des Naturhistorisches Museum & Edition Lammerhuber, 2012, ISBN 978-3-902421-68- 5 . (German English)
- Christian Koeberl, Georg Delisle, Alex Bevan: Meteorites from the desert. In: The Geosciences. 10, 8, 1992, pp. 220-225. doi: 10.2312 / geosciences.1992.10.220
- Georg Delisle: Antarctic Meteorites and Global Change. In: The Geosciences. 11, 2 1993, pp. 59-64. doi: 10.2312 / geosciences. 1993.11.59
- Rolf Froböse: The Antarctic - An Eldorado for meteorite researchers. In: Geosciences in Our Time. 2, 2, 1984, pp. 45-51. doi: 10.2312 / geosciences. 1984.2.45
- Monica M. Grady: Catalog of Meteorites. 5th edition. Cambridge University Press, Cambridge 2000, ISBN 0-521-66303-2 . (Book, CD and online)
- Joern Koblitz: Metbase. Electronic catalog. CD-ROM.
Relevant scientific journals
- Meteoritics & Planetary Science . (MAPS). Journal of the Meteoritical Society. Allen Press, Lawrence Kan 31.1996 ff.
- Geochimica et Cosmochimica Acta . (GCA). Journal of the Geochemical Society and the Meteoritical Society. Elsevier Science. New York NY 1.1950 ff.
- Earth and Planetary Science Letters . (EPSL). Elsevier, Amsterdam 1.1966 ff.
- Journal of Geophysical Research . (JGR). Series A – G. American Geophysical Union, Washington DC 54.1949 ff.
- Meteoritical Bulletin
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