home » Training » Introduction to the topic of meteorites. Meteorites. What meteorites consist of

Introduction to the topic of meteorites. Meteorites. What meteorites consist of

A meteor is called dust particles or fragments of cosmic bodies (comets or asteroids), which, when entering the upper layers of the Earth’s atmosphere from space, burn up, leaving behind us a streak of light that we observe. The popular name for a meteor is a shooting star.

Earth, is constantly subjected to constant bombardment by objects from space. They vary in size, from stones weighing several kilograms, to microscopic particles weighing less than a millionth of a gram. According to some experts, the Earth during the year captures more than 200 million kg of various meteor substances. And about one million meteors flare up per day. Only a tenth of their mass reaches the surface in the form of meteorites and micrometeorites. The rest, burns out in the atmosphere, causing meteor trails.

Meteoric matter usually enters the atmosphere at a speed of about 15km / s. Although, depending on the direction with respect to the motion of the Earth, the speed can vary from 11 to 73 km / s. Particles of medium size, when heated by friction, evaporate, giving a flash of visible light at an altitude of about 120km. Leaving a short-term trace of ionized gas and go out to a height of about 70 km. The greater the mass of the meteoroid, the brighter it flashes. These tracks, stored for 1015 minutes, can reflect radar signals. Therefore, to detect meteors that are too weak for visual observation (as well as meteors appearing in daylight), radar methods are used.

This meteorite was not observed during the fall. Its cosmic nature is established on the basis of the study of matter. Such meteorites are called finds, and they make up about half of the global collection of meteorites. The other half of the fall, fresh meteorites raised soon after they fell to Earth. These include the Peekskill meteorite, which began our story about space aliens. Falls are of great interest to specialists than finds: some astronomical information can be collected about them, and their substance is not changed by earthly factors.

Meteorites are usually given names according to the geographical names of places adjacent to the place of fall or find. Most often this is the name of the nearest settlement (for example, Peekskill), but more general names are assigned to outstanding meteorites. The two largest falls of the XX century. occurred on the territory of Russia: Tunguska and Sikhote-Alin.

Meteorites are divided into three large classes: iron, stone and iron-stone. Iron meteorites are composed mainly of nickel iron. In terrestrial rocks, a natural alloy of iron with nickel does not occur, so the presence of nickel in pieces of iron indicates its cosmic (or industrial!) Origin.

Nickel iron inclusions are found in most stone meteorites, so cosmic stones are usually heavier than earth stones. Their main minerals are silicates (olivines and pyroxenes). A characteristic feature of the main type of stone meteorites of chondrites is the presence of rounded chondra formations inside them. Chondrites consist of the same substance as the rest of the meteorite, but stand out in its section as separate grains. Their origin is not yet completely clear.

The third class of iron-stone meteorites is pieces of nickel iron interspersed with grains of rocky materials.

In general, meteorites consist of the same elements as terrestrial rocks, but combinations of these elements, i.e. minerals, may be those that are not found on Earth. This is due to the peculiarities of the formation of bodies that generated meteorites.

Among the falls, stony meteorites prevail. Means, such pieces more flies in space. As for the finds, iron meteorites predominate here: they are stronger, are better preserved in terrestrial conditions, stand out sharply against the background of terrestrial rocks.

Meteorites are fragments of minor planets of asteroids that inhabit mainly the zone between the orbits of Mars and Jupiter. There are many asteroids, they collide, crush, change each other's orbits, so that some fragments sometimes cross the Earth’s orbit during their movement. These fragments give meteorites.

It is very difficult to organize instrumental observations of meteorite incidence, with the help of which it is possible to calculate their orbits with satisfactory accuracy: the phenomenon itself is very rare and unpredictable. In several cases, it was possible to do this, and all the orbits turned out to be typically asteroid.

The interest of astronomers in meteorites was caused primarily by the fact that for a long time they remained the only samples of extraterrestrial matter. But even today, when the matter of other planets and their satellites becomes accessible to laboratory research, meteorites have not lost their significance. The substance that makes up the large bodies of the solar system underwent a lengthy transformation: it melted, divided into fractions, solidified again, forming minerals that no longer had anything to do with the substance from which everything was formed. Meteorites are fragments of small bodies that have not passed such a complex history. One of the types of meteorites, carbonaceous chondrites in general are a weakly modified primary material of the solar system. By studying it, experts will learn from what the large bodies of the solar system were formed, including our planet Earth.

Meteor shower

The bulk of the meteoric matter in the solar system revolves around the sun in specific orbits. The characteristics of the meteor swarm orbits can be calculated from observations of meteor tracks. Using this method, it was shown that many meteor swarms have the same orbits as comets known to us. These particles can be distributed throughout the orbit or concentrated in separate clusters. In particular, a young meteor swarm can remain concentrated for a long time near the parent comet. When, when moving in orbit, the Earth crosses such a swarm, we see a meteor shower in the sky. The perspective effect gives rise to the optical illusion that meteors, which actually move along parallel trajectories, seem to be emanating from one point in the sky, which is usually called a radiant. This illusion is the effect of perspective. In fact, these meteors are generated by particles of matter entering the upper atmosphere along parallel paths. This great number of meteors are observed for a limited period of time (usually several hours or days). Many annual flows are known. Although only some of them generate meteor showers. The Earth encounters a particularly dense swarm of particles very rarely. And then an extremely strong stream can occur with tens or hundreds of meteors every minute. Usually a good regular flow gives about 50 meteors per hour.

In addition to many regular meteor showers, sporadic meteors are observed throughout the year. They can come from any direction.

Micrometeorite

This is a particle of meteorite matter, which is so small that it loses its energy before it could ignite in the Earth’s atmosphere. Micrometeorites fall to the Earth like rain of the smallest dust particles. The amount of matter annually falling to the Earth in this form is estimated at 4 million kg. The particle size is usually less than 120 microns. Such particles can be collected during space experiments, and iron particles, due to their magnetic properties, can also be detected on the surface of the Earth.

Origin of meteorites

The rarity and unpredictability of the appearance of meteorite matter on Earth causes problems in its collection. Until now, meteorite collections are enriched primarily due to samples collected by random eyewitnesses of falls or simply by inquisitive people who drew attention to strange pieces of matter. As a rule, meteorites are melted from the outside, and their surface often bears a peculiar frozen ripple of regmaglipts. Only in places where heavy meteorite rains fall, does a targeted search for samples bring results. True, recently discovered places of natural concentration of meteorites, the most significant of them in Antarctica.

If there is information about a very bright fireball that could result in a meteorite falling, one should try to collect observations of this fireball by random eyewitnesses over the largest possible area. It is necessary that eyewitnesses from the observation site show the path of the car in the sky. It is advisable to measure the horizontal coordinates (azimuth and altitude) of some points on this path (beginning and end). In this case, the simplest instruments are used: a compass and an eclimeter an instrument for measuring angular height (this is essentially a protractor with a plumb bob fixed at its zero point). When such measurements are made at several points, they can be used to construct the atmospheric trajectory of the car, and then search for a meteorite near the projection to the earth of its lower end.

Collecting information about fallen meteorites and searching for their samples are fascinating tasks for astronomy lovers, but the statement of such problems is largely connected with some luck, luck, which is important not to miss. But observations of meteorites can be carried out systematically and bring tangible scientific results. Of course, professional astronomers armed with modern equipment are also engaged in such work. For example, they have at their disposal radars with which meteors can be observed even during the day. And yet, correctly organized amateur observations, which also do not require complex technical means, still play a role in meteorite astronomy.

Meteorites: falls and finds

Each meteorite falling to Earth allows you to increase the chances of finding answers to many questions about the origin of the Universe and the origin of life on Earth. These messengers of space several times led to an apocalypse on our planet. The threat of armageddon from a collision with a celestial stone occurs every few decades. Below are 15 interesting facts about meteorites:

Meteorites are considered only those cosmic bodies that have reached the Earth’s surface., but did not burn out in the layers of her atmosphere or flew back into outer space.
According to rough estimates, about 5-6 tons of celestial bodies fall on the Earth daily. And for the year this figure is 2,000 tons. The weight of individual specimens ranges from several grams to hundreds of kilograms and even tens of tons.
The largest crater (astroblem) from falling to the Earth of a cosmic body is in Antarctica and is called Wilkes Land Crater. Its diameter is 500 km. It is assumed that the meteorite that formed this crater fell 250 million years ago and caused Permian-Triassic extinction of 96% of marine and 70% of terrestrial living creatures on our planet. This crater was discovered in 1962. The second largest astrobleme is in Canada on the shores of the Hudson's Bay. Its diameter is 440 km.
The largest and oldest scientifically proven astrobleme with a funnel diameter of 300 km is located in South Africa. In the crater is the city of Wredefort, which gave the name to the funnel. The fall of the celestial body occurred 4 billion years ago.
The most famous meteorite funnel - Arizona. It is located in the US state of Arizona. This funnel has a diameter of 1200 meters and a depth of 230, with edges projecting up to 46 meters. The Arizona astrobleme was formed 50,000 years ago from the fall of a cosmic body with a diameter of 50 meters, a mass of 300,000 tons and flying at a speed of 50,000 km / h. Compared to the atomic bomb dropped on Hiroshima, the explosion in Arizona was 8,000 times more powerful.
In the 18th century, the Paris Academy of Sciences considered meteorites - stones of terrestrial origin, which are formed from lightning.
Due to the enormous speed (11 - 72 km / s) of meteorites with which they enter the Earth’s atmosphere, the destruction of the cosmic body occurs (burning and blowing off by a stream of atmospheric gases). Therefore, an insignificant part of them flies to the surface. From a multi-ton block, several kilograms may remain.
When a meteorite falls apart in flight, a meteor shower may form. Particularly large celestial bodies can cause disastrous consequences by meteor shower.
The largest cosmic body found is the Goba meteorite. He fell to Earth 80,000 years ago in Namibia. Slow fall rate allowed to survive a large part. Its mass is 66 tons, and its volume is 9 cubic meters. It consists of 84% iron and 16% nickel mixed with cobalt. According to the assumption, the initial mass of the meteorite body in contact with the Earth's surface was 90 tons. But the strike, time, vandals and researchers left only 60 tons.
The Goba Meteorite is the largest piece of iron on Earth of natural origin..
All cosmic bodies that have fallen to the Earth are divided into three groups according to their composition: iron (6% of falls), stone (93% of cases) and iron-stone.
Stone meteorites contain traces of organic compounds of unearthly origin. Therefore, there is a theory according to which life on Earth was brought from outer space.
Even stone meteorites have magnetic properties.. This is explained by the presence of nickel iron in their structure.
.
There are known cases of cosmic bodies falling into people and the death of a person from the effects of a shock wave caused by the fall of a cosmic body.
In 1969, the oldest meleorite in the Solar System fell and crushed in Mexico.. Of the estimated 5 tons, we managed to collect - 3. Among other things, Allende is the largest carbonaceous meteorite found on Earth.

Plan:

1 Terminology
2 The process of meteorites falling to Earth
3 Meteorite classification
- 3.1 Classification by composition
- 3.2 Detection classification
4 Traces of extraterrestrial organic matter in meteorites
- 4.1 Carbonaceous complex
- 4.2 Organized Elements
5 Large modern meteorites discovered in Russia
6 Interesting Facts
7 Individual meteorites

Introduction

Meteorite Willamette

The goba is the largest meteorite found. It is also the largest natural piece of iron on Earth.

Meteorite - a body of cosmic origin that fell on the surface of a large celestial object.

Most meteorites found weigh from a few grams to several kilograms. The largest of the meteorites found is the Goba (whose weight, according to estimates, was about 60 tons). It is believed that 5-6 tons of meteorites, or 2 thousand tons per year, fall on the Earth per day.

The existence of meteorites was not recognized by the leading academicians of the XVIII century, and hypotheses of extraterrestrial origin were considered pseudoscientific. It is alleged that the Paris Academy of Sciences in 1790 decided not to continue to consider reports of the fall of stones on Earth as an impossible phenomenon. In many museums, meteorites were removed from the collections so as not to make museums a laughing stock.

The Russian Academy of Sciences now has a special committee that oversees the collection, study and storage of meteorites. The committee has a large meteorite collection.

The meteorites were studied by academicians V.I. Vernadsky, A.E. Fersman, well-known meteorite research enthusiasts P.L. Dravert, L.A. Kulik and many others.

1. Terminology

A cosmic body before it enters the Earth’s atmosphere is called a meteoroid and is classified according to astronomical characteristics. For example, it can be cosmic dust, a meteoroid, an asteroid, their fragments, or other meteoric bodies.

A celestial body flying through the Earth’s atmosphere and leaving a bright luminous trace in it, regardless of whether it flies in the upper atmosphere and goes back into outer space, burns out in the atmosphere or falls on Earth, can be called either a meteor or a fireball. Meteors are considered bodies not brighter than the 4th magnitude, but fireballs - brighter than the 4th magnitude, or bodies whose angular dimensions are distinguishable.

A solid body of cosmic origin that fell to the surface of the Earth is called a meteorite.

At the site of the fall of a large meteorite, a crater (astroblem) can form. One of the most famous craters in the world is Arizona. It is assumed that the largest meteorite crater on Earth is Wilkes Earth Crater (diameter of about 500 km).

Other names of meteorites: aeroliths, sideroliths, uranoliths, meteorolites, betililiyam (baituloi), celestial, air, atmospheric or meteor stones, etc.

Phenomena similar to a meteorite falling on other planets and celestial bodies are usually called simply collisions between celestial bodies.

2. The process of meteorite impact on Earth

A meteoroid enters the Earth’s atmosphere at a speed of 11 to 72 km / s. At this speed, it begins to warm up and glow. Due to ablation (burning and blowing away by a free stream of particles of the substance of the meteoroid), the mass of the body flying to the surface can be less, and in some cases, significantly less than its mass at the entrance to the atmosphere. For example, a small body entering the Earth’s atmosphere at a speed of 25 km / s or more burns out almost without a trace. At such a rate of entry into the atmosphere from tens and hundreds of tons of initial mass, only a few kilograms or even grams of matter reaches the surface. Traces of the combustion of a meteoroid in the atmosphere can be found over almost the entire trajectory of its fall.

If the meteoroid does not burn out in the atmosphere, then as it slows down, it loses the horizontal velocity component. This leads to a change in the trajectory of the fall from, often almost horizontal at the beginning to almost vertical at the end. As it slows down, the glow of the meteoroid falls, it cools down (often indicate that the meteorite was warm rather than hot when it fell).

In addition, a meteoroid can be destroyed into fragments, resulting in meteor shower.

“Correct” round (not elongated) traces of meteorites are explained by explosive processes accompanying its fall at high speed.

3. Classification of meteorites

3.1. Classification by composition

stone
- chondritis
  - carbonaceous chondritis
  - common chondritis
  - enstatitis chondritis
- achondritis
iron stone
- palacites
- mesosiderite
iron

The most common are stone meteorites (92.8% of falls). They consist mainly of silicates: olivines (Fe, Mg) 2SiO4 (from fayalite Fe2SiO4 to forsterite Mg2SiO4) and pyroxenes (Fe, Mg) SiO3 (from ferrosilite FeSiO3 to enstatite MgSiO3).

The vast majority of stone meteorites (92.3% of stone meteorites, 85.7% of the total number of falls) are chondrites. They are called chondrites because they contain chondra - spherical or elliptical formations of a predominantly silicate composition. Most chondras have a size of no more than 1 mm in diameter, but some can reach several millimeters. Chondras are located in a detrital or fine-crystalline matrix, and often the matrix differs from chondras not so much in composition as in crystalline structure. The composition of chondrites almost completely repeats the chemical composition of the Sun, with the exception of light gases, such as hydrogen and helium. Therefore, it is believed that chondrites were formed directly from the protoplanetary cloud surrounding and surrounding the Sun, by condensation of matter and accretion of dust with intermediate heating.

Achondrites account for 7.3% of stone meteorites. These are fragments of protoplanetary (and planetary?) Bodies that underwent melting and differentiation in composition (into metals and silicates).

Iron meteorites are composed of an iron-nickel alloy. They make up 5.7% of falls.

Iron-silicate meteorites have an intermediate composition between stone and iron meteorites. They are relatively rare (1.5% drops).

Achondrites, iron and iron-silicate meteorites are classified as differentiated meteorites. They presumably consist of a substance that has undergone differentiation in the composition of asteroids or other planetary bodies. Previously, it was believed that all differentiated meteorites were formed as a result of the rupture of one or more large bodies, such as the planet Phaeton. However, an analysis of the composition of different meteorites showed that they were more likely to form from the fragments of many large asteroids.

Earlier, tektites, pieces of siliceous glass of shock origin, were isolated. But later it turned out that tektites are formed upon impact of a meteorite on a rock rich in silica.

3.2. Detection classification

fall (when a meteorite is found after observing its fall in the atmosphere);
finds (when the meteorite origin of the material is determined only by analysis);

4. Traces of extraterrestrial organic matter in meteorites

4.1. Carbonaceous complex

Carbon-containing (carbonaceous) meteorites have one important feature - the presence of a thin glassy crust, apparently formed under the influence of high temperatures. This crust is a good heat insulator, due to which minerals that cannot tolerate strong heating, such as gypsum, are stored inside carbonaceous meteorites. Thus, it became possible, when studying the chemical nature of such meteorites, to find in their composition substances that, in modern terrestrial conditions, are organic compounds of a biogenic nature:

Saturated hydrocarbons
- - Isoprenoids
  - n-alkanes
  - Cycloalkanes

Aromatic hydrocarbons
- - Naphthalene
  - Alkibenzenes
  - Acenaphthenes
  - Pyrenes

Carboxylic acids
- - Fatty acid
  - Benzene Carboxylic Acids
  - Hydroxybenzoic acids

Nitrogen compounds
- - Pyrimidines
  - Purines
  - Guanylurea
  - Triazines
  - Porphyrins

The presence of such substances does not allow us to clearly state the existence of life outside the Earth, since theoretically, subject to certain conditions, they could be synthesized and abiogenic.

On the other hand, if the substances found in meteorites are not products of life, then they can be products of pre-life - similar to the one that once existed on Earth.

4.2. Organized Elements

In the study of stone meteorites, the so-called "organized elements" are discovered - microscopic (5-50 microns) "unicellular" formations, often having distinct double walls, pores, spikes, etc.

Today it is not an undeniable fact that these fossils belong to the remains of any forms of extraterrestrial life. But, on the other hand, these entities have such a high degree of organization that it is customary to associate with life.

In addition, such forms are not found on Earth.

A feature of "organized elements" is also their multiplicity: per 1g. carbonaceous meteorite accounts for approximately 1800 “organized elements”.

5. Large modern meteorites discovered in Russia

Tunguska phenomenon (at the moment it is not clear exactly the meteorite origin of the Tunguska phenomenon. For details, see the Tunguska meteorite article). Fell on June 30, 1908 in the basin of the Podkamennaya Tunguska River in Siberia. Total energy is estimated at 15.40 megatons of TNT equivalent.
Tsarevsky meteorite (meteor shower). Fell on December 6, 1922 near the village of Tsarev, Volgograd Region. This is a stone meteorite. The total mass of collected fragments of 1.6 tons on an area of \u200b\u200babout 15 square meters. km The weight of the largest fallen fragment was 284 kg.
Sikhote-Alin meteorite (total mass of fragments 30 tons, energy is estimated at 20 kilotons). It was an iron meteorite. Fell in the Ussuri taiga on February 12, 1947
Vitim car. Fell in the area of \u200b\u200bthe villages of Mama and Vitimsky of the Mama-Chui district of the Irkutsk region on the night of September 24-25, 2002. The event had a great public outcry, although the total energy of the meteorite explosion is apparently relatively small (200 tons of TNT, with an initial energy of 2.3 kilotons), the maximum initial mass (before burning in the atmosphere) is 160 tons, and the final mass of fragments is of the order of several hundred kilograms.

A meteorite find is a rather rare occurrence. The meteoric laboratory reports: “In total, only 125 meteorites were found in the territory of the Russian Federation over 250 years.

6. Interesting facts

The only documented case of a meteorite entering a person occurred on November 30, 1954 in Alabama. A meteorite weighing about 4 kg pierced the roof of the house and ricocheted hit Anna Elizabeth Hodges on the arm and thigh. The woman received bruises.

In 1875, a meteorite fell in the region of Lake Chad (Central Africa) and reached, according to Aboriginal stories, 10 meters in diameter. After information about him reached the Royal Astronomical Society of Great Britain, an expedition was sent to him (15 years later). Upon arrival at the place, it turned out that he was destroyed by elephants, having fallen in love with him in order to sharpen his tusks. The funnel was destroyed by rare but heavy rains.

7. Separate meteorites

Omolon

Alfianello
Allende
Anthony
Arapahoe
Arcadia
Armel
Ashmore

Bansur
Barratta
Beaver
Beeler
Bencubbin
Bjurbole
Bledsoe
Bondoc
Boxhole
Breitscheid
Buenaventura

Calliham
Channing
Chainpur
Chico

A meteor is called dust particles or fragments of cosmic bodies (comets or asteroids), which, when entering the upper layers of the Earth’s atmosphere from space, burn up, leaving behind a strip of light that we observe. The popular name for a meteor is a shooting star.

Meteoric matter usually enters the atmosphere at a speed of about 15 km / s. Although, depending on the direction with respect to the motion of the Earth, the speed can vary from 11 to 73 km / s. Particles of medium size, when heated by friction, evaporate, giving a flash of visible light at an altitude of about 120 km. Leaving a short-term trace of ionized gas and fade to an altitude of about 70 km. The greater the mass of the meteoroid, the brighter it flashes. These tracks, stored for 10-15 minutes, may reflect radar signals. Therefore, to detect meteors that are too weak for visual observation (as well as meteors appearing in daylight), radar methods are used.

This meteorite was not observed during the fall. Its cosmic nature is established on the basis of the study of matter. Such meteorites are called finds, and they make up about half of the global collection of meteorites. The other half is the fall, "fresh" meteorites, raised shortly after they fell to the Earth. These include the Peekskill meteorite, which began our story about space aliens. Falls are of great interest to specialists than finds: some astronomical information can be collected about them, and their substance is not changed by earthly factors.

Nickel iron inclusions are found in most stone meteorites, so cosmic stones are usually heavier than earth stones. Their main minerals are silicates (olivines and pyroxenes). A characteristic feature of the main type of stone meteorites - chondrites - is the presence of rounded formations inside them - chondras. Chondrites consist of the same substance as the rest of the meteorite, but stand out in its section as separate grains. Their origin is not yet completely clear.

The third class - iron-stone meteorites - are pieces of nickel-iron with interspersed grains of rocky materials.

Meteorites are fragments of minor planets - asteroids, which inhabit mainly the zone between the orbits of Mars and Jupiter. There are many asteroids, they collide, crush, change each other's orbits, so that some fragments sometimes cross the Earth’s orbit during their movement. These fragments give meteorites.

The interest of astronomers in meteorites was caused primarily by the fact that for a long time they remained the only samples of extraterrestrial matter. But even today, when the matter of other planets and their satellites becomes accessible to laboratory research, meteorites have not lost their significance. The substance that makes up the large bodies of the solar system underwent a lengthy transformation: it melted, divided into fractions, solidified again, forming minerals that no longer had anything to do with the substance from which everything was formed. Meteorites are fragments of small bodies that have not passed such a complex history. One of the types of meteorites - carbonaceous chondrites - in general, is a weakly modified primary material of the solar system. By studying it, experts will learn from what the large bodies of the solar system were formed, including our planet Earth.

Meteor shower

In addition to many regular meteor showers, sporadic meteors are observed throughout the year. They can come from any direction.

Micrometeorite

Origin of meteorites

If there is information about a very bright fireball that could result in a meteorite falling, one should try to collect observations of this fireball by random eyewitnesses over the largest possible area. It is necessary that eyewitnesses from the observation site show the path of the car in the sky. It is advisable to measure the horizontal coordinates (azimuth and altitude) of some points on this path (beginning and end). In this case, the simplest instruments are used: a compass and an eclimeter - a tool for measuring angular height (this is essentially a protractor with a plumb bob fixed at its zero point). When such measurements are made at several points, they can be used to construct the atmospheric trajectory of the car, and then search for a meteorite near the projection to the earth of its lower end.

Meteorites: falls and finds

I must say that the scientific world until the end of the XVIII century. He was skeptical of the very possibility of stones and pieces of iron falling from the sky. Reports of such facts were considered by scientists as manifestations of superstition, because at that time no celestial bodies were known, the debris of which could fall to Earth. For example, the first asteroids - minor planets - were discovered only at the beginning of the XIX century.

The first scientific work, claiming the cosmic origin of meteorites, appeared in 1794. Its author, the German physicist Ernst Hladni, managed to give a single explanation for three mysterious phenomena: the passage of fireballs across the sky, the fall of melted pieces of iron and stone on the Earth after flights, and the finds of strange melted blocks of iron in different places of the Earth. According to Khladni, all this is connected with the arrival of cosmic matter on Earth.

Incidentally, one of such unusual iron blocks was the multi-pood “krytsa” exported by Russian academician Peter Simon Pallas from Siberia and laid the foundation for the national collection of Russian meteorites. This iron block with olivine mineral grains included in it was named “Pallas Iron” and subsequently gave the name to a whole class of iron-stone meteorites - pallastites.

Antarctica

Although meteorites are falling all over the globe, most often they fall into the oceans and sink to the bottom. But there is on Earth, in eastern Antarctica, vast barren plains of blue ice. On these plains from time to time pieces of rock are found.

Studies of meteorite fall sites

A bright dash in the sky, recorded almost at dusk on August 13, 1999, is not a flash of a meteor, but a “solar bunny” from a satellite. This satellite, Iridium-52, is one of the family of Iridium digital communications satellites. “Flashes” are caused by the reflection of sunlight from smooth antennas.

One of the 100,000 meteorites falling to Earth has a destructive force. Over the past 200 years of observations in the United States, 23 meteorites fell into the home, and 4 meteorites in the territory of the former USSR.

1511 Genoa (Italy). During a solar eclipse, a meteor shower fell. As a result, several fishermen and a priest were killed. 1684 Tobolsk (Russia). As a result of a meteorite fall, the dome of the church was broken. 1836 Brazil. A sheep was killed as a result of a meteorite fall. 1911 Egypt. A dog was killed by a fallen meteorite.

On November 12, 1982, in Wesersfield (Connecticut, USA), Robert and Wanda Donahue sat in the evening at the TV, when there was a blow in the hallway and the sound of crumbling plaster was heard. Elderly spouses found a hole the size of a human head in the roof of the house and ceiling, and in the kitchen under the table a stone meteorite with a diameter of 13 cm and a mass of 2.7 kg. the scientists who arrived on call were not too lazy to even look into the vacuum cleaner with which the owners cleaned before the guests arrived. and found there are several fragments of a meteorite. The meteorite was in the collection and was named Donahue.

On October 9, 1992, at 8 p.m., a stone meteorite weighing 12.3 kg fell in the city of Peekskill (state of New York, USA) on the trunk of a car in the courtyard and, due to impact, split into several parts, crushing the trunk heavily. The young mistress of the car ran out into the noise. The meteorite was still warm. She reported to the nearest university. A few hours later, scientists, collectors, museum staff, the press, representatives of the Sotheby's auction, etc. gathered at the house. Scientists have confirmed that this is a stone meteorite (chondrite) and the hostess received $ 70,000 for it. So the stone that fell from the sky was fortunately.

Chicxulub Crater

A large terrestrial impact crater on the northern coast of the Yucatan Peninsula in Mexico, currently largely hidden by sedimentary rocks. It is believed that it is associated with the shock event that occurred 65 million years ago, which, apparently, was the cause of the mass extinction of living creatures, including dinosaurs.

Goba Meteorite

The largest known meteorite in the world. Its size is 3x3x1 m. It belongs to the type of iron meteorites and weighs approximately 55,000 kg. It is still at the crash site in Namibia, where it was discovered in 1928. The meteorite is covered with a layer of rusty eroded substance; taking into account erosion, the initial mass of the meteorite should exceed 73,000 kg.

Sikhote-Alin rain

A large meteor shower fell on February 12, 1947 in eastern Siberia. The largest meteorite found weighed 1745 kg, but according to available estimates, thousands of fragments fell on the Earth's surface, the total weight of which reaches 100 tons. Most of them were not found.

The largest meteorite from museums in the world. This iron meteorite was found by Robert Peary in Greenland in 1897. Weight - 31 tons. Exhibited at the Hayden Planetarium in New York.

Interesting stories

On October 9, 1992, America lived on the expectation of Columbus Day: the 500th anniversary of the discovery of the New World by the great navigator was approaching. 18-year-old Michelle Napp from the small town of Peekskill (New York) watched TV in the evening. Suddenly she heard a loud noise in the street. The girl was frightened and called the police on the phone, which established that this time the space wanderer was the “intruder”: next to the damaged machine Nappov was a melted stone of almost 9 kg.

This case is an exception rather than a rule: stones or pieces of iron falling from the sky - they are called meteorites - behave surprisingly peacefully towards people. Only two cases are reliably recorded

Peekskill Town

When the Peekskill meteorite flew over the United States in 1992, 16 people managed to film it before it crashed into a car. This spectacular car crossed the airspace of several US states in 40 seconds of its flight, until it landed in Peekskil, a suburb of New York.

The most famous meteorite falls

While Colby Navarro was working at a computer, a cobblestone from outer space broke into the roof of the house, hit the printer, hit the wall and remained lying near the catalog box. This happened around midnight on March 26 in the town of Forest Park, Illinois (USA) near Chicago.

Meteorite in Chicago

hit of meteorites in people (both without serious consequences) is negligible and the material damage caused by them. There is no mysticism in this “friendliness”: a meteorite’s fall is a rare phenomenon and can happen with equal probability anywhere in the world. And people still do not take up much space on their planet. So heavenly wanderers fall into the oceans, which account for more than 2/3 of the earth's surface, into vast deserted deserts, forests, and polar regions - in full accordance with the laws of mathematical statistics. Therefore, each of us not only practically does not risk getting a meteorite strike, but even has very little chance of seeing it fall.

However, do not despair. Everyone can observe the arrival of cosmic matter on Earth. It is enough to spend at least an hour on a clear night, peering into the starry sky, and you will surely notice a fiery line cutting through the firmament. This is a shooting "star" or meteor. Sometimes there are many of them - whole stellar showers. But no matter how many of them fly, the view of the starry sky will not change: shooting stars have nothing to do with real stars.

In outer space surrounding our planet, many solid bodies of various sizes move - from dust particles to lumps with diameters of tens and hundreds of meters. The larger the size of the bodies, the less often they occur. Therefore, dust particles collide with the Earth daily and hourly, and lumps - once in hundreds or even thousands of years.

The effects accompanying these collisions are completely different. A small body weighing a fraction of a gram, invading the Earth’s atmosphere with great speed (tens of kilometers per second), is heated by friction against the air and completely burns at a height of 80-100 km. An observer on Earth sees a meteor at this moment. If a larger piece flies into the atmosphere, for example, the size of a fist, and not at the highest speed, the atmosphere can act as a brake and extinguish cosmic speed before the piece completely burns out. Then its remainder will fall to the surface of the Earth. This is a meteorite. A meteorite fall is accompanied by a flight of a ball of fire across the sky and thundering sounds. Few have seen such phenomena. Finally, when the mass of the incoming body is even larger, the atmosphere can no longer extinguish its entire speed, and it crashes into the Earth’s surface, leaving a cosmic scar on it - a meteorite crater or crater.

If you look at the Moon through a telescope, you can see that its entire surface is literally pitted with such craters - traces of the meteorite bombardment that the Moon underwent in the past. Earth also received space strikes in the past (see the article “Asteroid Threat”). Their traces in the form of meteorite craters (sometimes called astroblems - “star wounds”) remained on the surface of our planet. The most famous of them - a crater in Arizona - has a diameter of more than 1 km and was formed 50 thousand years ago. The dry climate of the desert ensured its good preservation. External traces of other cosmic scars are largely erased by subsequent geological processes. One of the largest known such formations is located in the north of Siberia. This is the Popigai meteorite crater with a diameter of 100 km.

One in almost two centuries. This is the chance of a meteorite getting into a person according to astronauts. Officially recorded only one case. In the middle of the last century, the celestial body fell into Ann Hojesi. The American injured her shoulder and thigh. Injuries were not serious. The woman survived. A meteorite pierced the roof of her house in 1954. On the same day, as on any other day, approximately 4 billion celestial bodies fell to Earth. Such is the statistics of scientists. But what is a meteorite from their point of view and in the eyes of other specialists?

What is called a meteorite?

Meteorites are celestial bodies that fell to Earth from space. From Greek, the concept is translated as "a stone from heaven." However, the composition of meteorites is not only stone, but also stone-metal and pure metal. Meteorites, unlike meteors, are large. The surface of the earth, at times, reaches the body with a human fingernail. However, meteors do not reach the soil at all. From the aerodynamic load in the atmosphere, they burn out. This indicates the initially smaller sizes of these celestial bodies. By the way, the translation of their name literally sounds like a "heavenly phenomenon."

The photo shows the movement of particles to the planet.

Meteor fallingflows at speeds of 5-20 kilometers per second. The surface of the planet reaches no more than 10 percent of the initial mass of meteorites. From friction in the atmosphere, 90 percent of matter burns out. This creates a glow. People call it shooting stars or meteor shower in cases of mass fall of bodies.

A prerequisite is that the meteorite must be smaller than the object on which it falls. In addition, the block has a melted surface. Its occurrence is inevitable when the body passes through the atmosphere. The largest celestial bodies found on Earth weigh tens of tons. The standard weight of most "aliens" is 1-2 kilograms. On the most significant meteorites, further.

Known meteorites

Until the 18th century, there was no scientific evidence, calculations at the expense of meteorites. Society perceived celestial phenomena as signs, the wrath of the Gods. Meteorites found on the ground could not be distinguished from simple stones.

Pictured is the Palasovo Iron

The first celestial body to fall officially is the Palasovo Iron. The name is derived from the surname of a scientist who found and exported a multi-pound lump from Siberia. The meteorite became the first-born of the Russian assembly of celestial bodies. It is no coincidence that the word “iron” is present in the name of the “alien”. The meteorite is completely metal. It was found in the middle of the 19th century, when asteroids and the nature of meteorites were already known to science.

Palace iron belongs to the class of "finds". So called meteorites, the fall of which they did not see and discovered that long after it. In the category of “finds” is located the largest of the bodies found on Earth, this is “Goba”. The fact is that meteorite fell80,000 years ago, but a farmer from Nanibia named Goba found him. A resident of Africa discovered a celestial body near his lands in the 1920th.

In the photo, a falling meteorite

The weight of the Goba meteorite is 66 tons. So far, the record has not been broken. The lump is metallic. It is declared a national treasure. The land on which the meteorite lies is donated by the farmer to the state. Interestingly, the Goba is one of the few bodies that did not leave a large-scale crater. Geologists suggest that the atmosphere greatly slowed the fall of the meteorite due to its large area. This reduced the energy release in a collision with the soil.

In the photo, the Goba meteorite

To be larger than the Goba could only Tunguska meteoritebut this celestial body has not yet been found. According to scientists, the weight of the "alien" should be at least 100 tons. The highest mark is 500 tons. This is evidenced by the nature of the appearance of the meteorite and the consequences from it.

In the photo the Tunguska meteorite, more precisely its fragments

In the sky, the body looked like a huge ball. He appeared over the Tunguska taiga on June 30 in 1908. The meteorite exploded, not reaching the Earth at an altitude of about 7-10 kilometers. The phenomenon occurred over a dense forest. When astronomers, geologists, and journalists reached the point of explosion, they saw fallen trees. In an area of \u200b\u200b2,000 square kilometers, even centuries-old trunks were demolished by a blast wave.

At a distance of thousands of kilometers from the Tunguska taiga, windows in houses were knocked out. But, only miniature silicate balls were found. Not even a crater from a meteorite was found. Therefore, they still argue about the argument, but was the celestial phenomenon a meteorite?

In the photo Irkutsk meteorite

The most famous fallen meteoriteuntil recently, it was called Irkutsk. He also exploded in the sky. An event occurred in the 2002th. Heavenly body found. Its mass is only slightly inferior to the Goba meteorite. Outperformed the Irkutsk "alien" Chelyabinsk meteorite. He fell in 2013. NASA experts estimated the mass of the body entering the atmosphere at 10,000 tons. The figure breaks all records. But, the meteorite did not maintain its integrity and did not reach the soil. It also exploded, splitting into millions of particles. By the nature of the damage, the consequences, the nature of the fall precisely Chelyabinsk meteoriteequate to Tunguska. Unlike the latter, fragments of the “alien” of 2013 were still found.

Meteorite hypotheses

The main hypothesis of the origin of fragmentation meteorites. It is believed that celestial bodies separated from asteroids and planets. On the chemical composition found clumps identical to the surface of Mars, Venus, the Moon. This gives scientists a reason to think that when they collide with any celestial bodies, lumps falling afterwards onto other planets are separated from the planets of the solar system and other systems.

In the photo, a meteorite made of iron

By the way, meteorites can be bought. They, for example, are sold at auctions in the United States. Per gram gave a minimum of 1 dollar, and a maximum of 1,000 conventional units. Most profitably sold "aliens" from Mars. Many people, including specialists, believe that meteorites are the source of life, that it was they who once brought life to Earth.