How dangerous is the threat from outer space, what to do with the found meteorite? What is the largest meteorite that has fallen to earth.

Chelyabinsk meteorite - why was it not tracked, can we expect new ones to fall and how strong is the meteorite threat? Astronomers speak.

All about meteorites

Alexander Bagrov, Doctor of Physical and Mathematical Sciences, Leading Researcher of the Space Astrometry Department of the Institute of Astronomy of the Russian Academy of Sciences (INASAN).

About meteorites

- To answer the question about the origin of meteorites, it is necessary to tell about the origin of the solar system. According to my research, it turns out that the solar system arose about 5 billion years ago. Moreover, the planets arose before the sun arose. The idea that is contained in the Six Days fell into my soul very much, that at first God created the Earth, grass already grew on it, and the Sun arose only on the third day of biblical creation.

We also believe that all the planets first arose, and then the Sun flared up and became a star. The most interesting thing is that the ignition of the Sun coincided with the situation when one of the planets that was between Mars and Jupiter exploded, its fragments scattered throughout the solar system, and now make up the so-called Asteroid Belt. It is possible that the fall of these fragments onto the surface of the then still cold Sun caused the onset of nuclear reactions on the Sun, that is, it ignited this star.

Fragments from the Asteroid Belt can enter our atmosphere. If they do not burn up in the atmosphere, then they fall to the ground, and when we find them, we call them meteorites.

What happened in the sky over Chelyabinsk?

There was a fireball phenomenon over Chelyabinsk - one meteorite flew over the city. This is not a meteor shower, as some journalists say. A meteor shower is the fall of numerous meteorites. As the song says: “One snowflake is not yet snow, one rain is not yet rain,” so one meteorite is not yet a meteor shower.

A meteorite is what we found on earth, and cosmic bodies fly in space. Large bodies are called asteroids, small bodies are called meteoroids. If the body burned up in the atmosphere, then it is called a meteor, if it flew, then the substance found is called a meteorite.

In space, every body moves in its own orbit, and if it does not collide with anything, then it can fly in its orbit for billions of years. But it collides with various elements of the solar system, such as photons that fly from the Sun. Each collision leads to a small change in the orbit. If this change causes the body to meet a planet on its way, then it crashes into it. If this is our planet, then we are seeing starfall, shooting stars, meteors, or meteorites. Every day, dozens of meteors fly over our heads, and millions of meteors fly over the entire earth. The earth has existed for billions of years, and you can imagine how much everything flew in and burned up above the earth. If the cosmic body has sufficient mass, then it does not have time to burn out entirely and reaches the earth. So in 1947 the Sikhote-Alin meteorite fell to the ground. 70 tons of iron flew, and 27 tons were found on the ground.

Why is a meteorite hard to track?

Let me give an analogy - if we cross the road, then we looked to the left and right in search of dangerous bodies - cars. We do not follow the insects under our feet. It is the same here - we don’t even have in our thoughts to keep an eye on small celestial bodies, because they are not dangerous. Dangerous bodies are those whose diameter is above 140 m. The whole world is thinking about how to competently organize a service in order to monitor them. And the meteorite over Chelyabinsk is only a few meters in diameter. You will not see a bug at a distance of 10 km, and it flies these 10 km in a second. It is impossible to keep track of them, and it is useless.

In Russia and in the world, the monitoring system has not been established. The largest asteroids are tracked, but they fly far from the earth, in the region of the Asteroid Belt. Sometimes smaller asteroids fly up to us, but closer. The appearance of such a small asteroid is as sensational as the approach of asteroid 2012 DA14 is now.

Did meteorites harm people?

There was once a case when, I think in the 14th century, a meteorite killed a Chinese. History does not know when a meteorite killed someone other than this Chinese. Sometimes they caused damage. A few years ago, a meteorite hit the roof of an American woman's house. She got more money for it than the whole house was worth.

If the Tunguska meteorite in 1908 would have exploded not over the taiga?

The damage would be very significant. The power of its explosion is estimated at 50 megatons of TNT equivalent, trees in the taiga were knocked down over an area of ​​several thousand square meters. kilometers. If the explosion had occurred over St. Petersburg, then there would be little left of the city.

Should we expect new meteorites?

– This is to be expected, because a lot of things fly in space. In order to keep track of all of them, the system has not yet been created. The threat they pose is high enough for us to think about it. Now the question of a tracking system is being raised and, moreover, the question of creating a countermeasure system is being raised. If such a dangerous body flies to the ground, then you need to get rid of it.

Are there developments in Russia of a system for counteracting meteorites?

Developments are underway, but only at the level of papers, words and ideas, because any equipment costs money, and the money we have in Russia goes to the oligarchs.

Yuri Pidoprygora, astronomer, Ph.D. in physics and astronomy, researcher at the radio astronomical observatory in the village of Dwingeloo in the north of the Netherlands.

From the point of view of astronomy, the phenomenon is unremarkable, the falls of celestial bodies of this magnitude (it is still difficult to accurately estimate the size of a meteoroid or microasteroid, but it clearly does not exceed a couple of meters) occur on average once every few months, well, maybe once a year.

Once upon a time, astronomy was taught in schools and there was such a topic, “Meteors and fireballs”. Young astronomers went on meteor patrols in the summer and everyone dreamed of seeing such a fireball as it flew over Chelyabinsk today. In textbooks and reference books there were diagrams on how to correctly mark the passage of such a celestial body and the address was attached where to send the report in case of luck ...

NASA estimates the size of the Chelyabinsk microasteroid at 15 meters. If this is true, then this event is more unique than previously thought - perhaps the most interesting since the famous explosion over Tunguska.

The only interesting thing here is that the trajectory ran over relatively densely populated areas. And, of course, a funny coincidence in time with the “close” (~ 30,000 km) flyby of the asteroid DA14, which has been much talked about in the press in recent days, which led to a bunch of “misunderstandings” (it would be nice to know how accidental or intentional ) when covering this event in the media.

Even the monitoring of truly dangerous large nearby asteroids is currently being carried out at a far from adequate level, to say nothing of small pebbles. There is another problem - near-Earth orbits are clogged with space debris, which, by and large, no one cares about either. So it’s still good if just a stone falls on your head, and not a barrel with a ton of highly toxic rocket fuel or a spent nuclear reactor ...

Meteorites, super category of finds with a metal detector. Expensive and replenished regularly. The only problem is how to distinguish a meteorite... Finds that look like a stone and give a response from a metal detector are not uncommon on detecting. At first, he tried to rub it against the blade of a shovel, and over time, he collected in his head the characteristic differences between celestial meteorites and earthly shmurdyak.

How to distinguish a meteorite from an artifact of terrestrial origin. Plus photos from the search engine forum, finds of meteorites and similar ones.

The good news is that 5000-6000 kilograms of meteorites fall on the earth in 24 hours. It is a pity that most of them go under water, but there are enough of them in the ground.

How to distinguish a meteorite

Two important properties. A meteorite never has an internal horizontal structure (layers). The meteorite does not look like a river stone.

Melted surface. If there is, that's a good sign. But if the meteorite lay in the ground or on the surface, the surface may lose its glaze (by the way, it is most often thin 1-2 mm).

The form. A meteorite can have any shape, even square. But if it's a regular ball or sphere, it's most likely not a meteorite.

magnetize. Almost all meteorites (about 90%) stick to any magnet. But the earth is full of natural stones with the same properties. If you see that it is metal, and it does not stick to a magnet, this find is most likely of terrestrial origin.

Appearance. Meteorites in 99% do not have inclusions of quartz and there are no "bubbles" in them. But often there is a grain structure. A good sign is "plastic dents", something like fingerprints in plasticine (the scientific name for such a surface is Regmaglipty). Meteorites most often contain iron, which, once on the ground, begins to oxidize, it looks like a rusty stone))

Photos of finds

There are a lot of photos of meteorites on the Internet ... I'm only interested in those that were found with a metal detector by ordinary people. Found and doubt whether it is a meteorite or not. Forum thread (bourgeois).

The usual expert advice is something like this ... Pay attention to the surface of this stone - the surface will definitely have dents. A real meteorite flies through the atmosphere, while it heats up very much and its surface “boils”. The upper layers of meteorites always retain traces of high temperature. Characteristic dents, similar to bursting bubbles, are the first characteristic feature of a meteorite.

You can try the stone for magnetic properties. Simply put, bring a magnet to it and move it over it. Find out if the magnet sticks to your stone. If the magnet sticks, then there is a suspicion that you really became the owner of a piece of a real celestial body. This type of meteorites is called iron. It happens that the meteorite does not magnetize too strongly, only in some fragments. Then it's probably a stony-iron meteorite.

There is also a type of meteorites - stone. It is possible to detect them, but it is difficult to determine that this is a meteorite. Here you can not do without chemical analysis. A feature of meteorites is the presence of rare earth metals. And it also has melting bark on it. Therefore, the meteorite is usually very dark in color. But there are also white ones.

Debris lying on the surface is not considered subsurface. You are not breaking any laws. The only thing that may sometimes be required is to obtain the opinion of the Committee on Meteorites of the Academy of Sciences, they must conduct research, assign a class to the meteorite. But this is if the find is very impressive, and it is difficult to sell it without a conclusion.

At the same time, it is impossible to argue that the search and sale of meteorites is an insanely profitable business. Meteorites are not bread, queues do not line up behind them. You can sell a piece of the "heavenly wanderer" more profitably abroad.

There are certain rules for the export of meteorite material. First you need to write an application to the Protection of Culture. There you will be sent to an expert who will write a conclusion whether the stone is subject to export. Usually, if it is a registered meteorite, there are no problems. You pay a state duty - 5-10% of the cost of the meteorite. And forward to foreign collectors.

In 2002, according to American satellite data, a space object fell in the Irkutsk region. According to the data provided then by three Irkutsk and two Moscow scientists, no traces of a meteorite fall were found.

Examination of a vast area of ​​taiga in the Bodaibo region by the expedition began in early July and continued for thirty days. During this time, thirty people included in the expedition group examined the territory of the taiga with an area of ​​​​more than 250 square kilometers in the hope of finding traces of the fall or individual fragments of the Vitim fireball. The starting point of the search was the place where, according to data received from the American satellite, a celestial body fell to the Earth's surface.

The scientific organization of labor is not only laboratory research, sometimes in order to obtain scientific evidence it is necessary to overcome difficult terrain on foot to search for evidence and facts. Members of the third expedition patrolled the mountains and various gorges in order to find any evidence of an anomalous phenomenon - craters, fall marks, forest falls. Valery Andreev and Anatoly Skibitsky, local hunters, who themselves were professional geologists in the recent past, provided invaluable assistance in the search. Even before the arrival of the expedition, the hunters carried out a preliminary survey of that part of the taiga, where, according to the assumption, the fireball could fall.

The expedition members managed to find several places with fallen forest, the trees in which were definitely damaged by a meteorite. The tops of the trees were found from the remaining trunks at a distance of up to ten meters, which indicates a significant force of the shock wave. The difficult terrain, as well as deep moss and elfin cedar, became an obstacle to the search, due to which some places for the search were inaccessible.

Scientists say that the main task was to detect craters or material traces of the fall of the fireball, but in the end nothing of the kind was found. From this we can conclude that the rate of fall was so high that the meteorite fell apart in the air due to the pressure drop. Soil and moss samples were taken at the sites of forest tree fallouts. Four samples are in Irkutsk, several more were sent to Moscow to the State Committee on Meteorites.

The fact that the fact of a meteorite fall took place is confirmed not only by data from the American satellite, but also by eyewitness accounts. But therein lies the contradiction. According to information received from local residents, the meteorite could fall much further than the place indicated in the information received from the American satellite.

The Vitim meteorite was most likely a comet

Scientists from the International Research Association "Kosmopoisk", having studied the site of the fall of the Vitim meteorite, came to the conclusion that, most likely, we are talking about a collision with the Earth in 2002 of a huge comet.

“When we arrived at the site of the fall of the cosmic body, we found a picture similar to the one that scientists observed at the site of the fall of the Tunguska meteorite. I am convinced that in this case we are faced with a comet falling to Earth, because meteorites do not leave radioactive elements and do not harm human health in any way, ”Vadim Chernobrov, head of Kosmopoisk, said at a press conference in Moscow on Friday.

In support of this hypothesis, he said that three days after the fall of the meteorite, diseases associated with pressure worsened among local residents, seven days later - with the kidneys and joints. “In addition, the radioactive background has doubled. However, at present it no longer exceeds 16-17 micro-roentgens per hour - a value that is harmless to human health, ”added Chernobrov.

Meanwhile, the head of Kosmopoisk noted that the consequences of a meteorite fall in the area of ​​the Vitim River on the night of September 24-25, 2002 are comparable to the destruction caused by an air bomb explosion with a capacity of 200 kilotons to 1 megaton in TNT equivalent.

The epicenter of the fall of a celestial body is an irregular ellipse (the length of the axes is 10 and 6 km) with a continuous fall of the forest. In a zone measuring 3 x 2 km, traces of a fire are observed, the alleged radiation burn on the tops of the mountains can be traced at a distance of at least 10 km from the epicenter.

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The Chelyabinsk fireball drew attention to space, from where asteroids and meteors can be expected to fall. Interest in meteorites, their search and sale has increased.

Chelyabinsk meteorite, photo from Polit.ru

Asteroid, meteor and meteorite

flight paths asteroids designed for a century ahead, they are constantly monitored. These cosmic bodies potentially dangerous for the Earth (the size of a kilometer or more) shine with light reflected from the Sun, so they appear dark from the Earth part of the time. Amateur astronomers are not always able to see them, as city lighting, haze, etc. interfere. Interestingly, most of the asteroids are discovered not by professional astronomers, but by amateurs. Some are even awarded international prizes for this. There are such lovers of astronomy in Russia and other countries. Russia, unfortunately, is losing because of the lack of telescopes. Now that the decision to fund the work to protect the Earth from space threats has been made public, scientists have the hope of acquiring telescopes that can scan the sky at night and warn of imminent danger. Astronomers also hope to receive modern wide-angle telescopes (at least two meters in diameter) with digital cameras.

smaller asteroids, meteoroids, flying in near-Earth space outside the atmosphere, can be seen more often when they fly close to the Earth. And the speed of these celestial bodies is about - 30 - 40 km per second! The flight of such a "pebble" to the Earth can be predicted (at best) only one or two days in advance. In order to understand how small this is, the following fact is indicative: the distance from the Moon to the Earth is overcome in just a few hours.

Meteor looks like a shooting star. It flies in the Earth's atmosphere, often adorned with a burning tail. Real meteor showers happen in the sky. They are more properly called meteor showers. Many are already known. However, some happen unexpectedly when the Earth encounters rocks or pieces of metal roaming the solar system.

fireball, a very large meteor, appears to be a fireball with sparks flying in all directions and a bright tail. The fireball is visible even against the background of the daytime sky. At night, it can illuminate vast areas. The path of the fireball is marked with a smoky stripe. It has a zigzag shape due to air currents.

When a body passes through the atmosphere, a shock wave is generated. A strong shock wave is capable of shaking buildings and the ground. It generates blows similar to explosions and roar.

A space body that has fallen to Earth is called meteorite. This is the rock-hard remnant of those meteoroids lying on the ground that were not completely destroyed during their movement in the atmosphere. In flight, air resistance begins braking, and kinetic energy is converted into heat and light. The temperature of the surface layer and the air shell in this case reaches several thousand degrees. The meteor body partially evaporates and throws out fiery drops. The fragments of the meteor during the landing quickly cool down and fall to the ground warm. From above they are covered with a bark of melting. The place of fall often takes the form of a depression. L. Rykhlova, head of the department of space astrometry at the Institute of Astronomy of the Russian Academy of Sciences, reported that “about 100 thousand tons of meteoroid matter falls on the Earth every year” (“Echo of Moscow”, 17.02.2013). There are very small and fairly large meteorites. So, the Goba meteorite (1920, South-West Africa, iron) had a mass of about 60 tons, and the Sikhote-Alinsky meteorite (1947, the USSR, which fell with iron rain) - an estimated mass of about 70 tons, collected 23 tons.

Meteorites are made up of eight basic elements: iron, nickel, magnesium, silicon, sulfur, aluminum, calcium, and oxygen. There are other elements, but in small quantities. Meteorites vary in composition. The main ones are: iron (iron combined with nickel and a small amount of cobalt), stony (combination of silicon with oxygen, metal inclusions are possible; small rounded particles are visible at the break), iron-stone (an equal amount of stony and iron with nickel). Some meteorites are of Martian or lunar origin: when large asteroids fall on the surface of these planets, an explosion occurs, and parts of the surface of the planets are ejected into space.

Sometimes meteorites are confused with tektites. These are small black or greenish-yellow molten pieces of silicate glass. They are formed at the moment of the impact of large meteorites on the Earth. There is an assumption about the extraterrestrial origin of tektites. Outwardly, tektites resemble obsidian. They are collected, and jewelers process and use these "precious stones" to decorate their products.

Are meteorites dangerous to humans?

Only a few cases of direct hits of meteorites on houses, cars or people have been recorded. Most of the meteorites end up in the ocean (almost three-quarters of the earth's surface). Densely populated and industrial areas occupy a smaller area. The chance of hitting them is much less. Although sometimes, as we see, this happens and leads to great destruction.

Can you touch meteorites with your hands? They are not considered to pose any danger. But taking meteorites with dirty hands is not worth it. They are advised to immediately put in a clean plastic bag.

How much does a meteorite cost?

Meteorites can be distinguished by a number of features. First of all, they are very heavy. On the surface of the “stone”, smoothed dents and depressions (“fingerprints on clay”) are clearly visible, there is no layering. Fresh meteorites are usually dark, as they melt as they fly through the atmosphere. This characteristic dark melting crust is about 1 mm thick (more common). A meteorite is often recognized by its blunt head. The fracture is often gray in color, with small balls (chondrules) that differ from the crystalline structure of granite. Iron inclusions are clearly visible. From oxidation in air, the color of meteorites that have lain on the ground for a long time becomes brown or rusty. Meteorites are highly magnetized, causing the compass needle to deviate.

It seems completely defenseless - a tiny blue ball, wrapped in a thin atmosphere, which, it seems, can be blown away by the lightest breeze. It becomes a little creepy when you realize that if a very small asteroid the size of Moscow falls to Earth, hard times will come for life. However, at different points in its history, the Earth has already been subjected to the fall of large meteorites and, as you can see, is still intact. Let's remember the most famous of them.

Tunguska meteorite

This meteor flew through the earth's atmosphere over Siberia in 1908 and exploded just a few kilometers from the Siberian surface.

The explosion had the force of an atomic bomb and knocked down trees within 800 square kilometers. It took years for scientists to start exploring the abandoned and uninhabited area; a hundred years later, they are still looking for conclusive evidence of a meteorite impact in the form of a crater or body debris.

They say a meteorite hit Nikola Tesla, but that's just another conspiracy theory.

Someone believes that the crater is hiding in a nearby lake. Others believe that at the last moment, an alien ship destroyed the meteorite so that it would not destroy the Earth. Well, we have a lot to learn from aliens.

As you know, dinosaurs died, most likely due to an asteroid impact. Together with them, more than half of all species on the planet died. Scientists aren't 100% sure that it was this asteroid that triggered the so-called KT extinction, but they have some reason to believe that the villain came from outer space.

Most of the soil during the event (K-T layer) contains a lot of iridium, which is abundant on asteroids, but scarce on Earth.

Scientists believe that about 65 million years ago, one or more iridium comets or meteorites fell to Earth, kicking dust into the atmosphere and causing massive climate change. Where did this guest go? No one knows, but some researchers believe that a crater on the Yucatan Peninsula in Mexico is the place.

Weighing 60 tons, the Hoba meteorite, which still lies in its place in Namibia, is the largest known meteorite on the planet. A flat slab of iron fell to the ground about 80,000 years ago, so we don't know for sure what pyrotechnic show accompanied its arrival, but it wasn't discovered until 1920 when a farmer was digging through his field and stumbled upon the metal top. Since then, Khoba has become a national treasure, attracting thousands of visitors every year.

Weighing approximately 15 tons and three meters high, this massive bony piece of iron is believed to be the remnant of the iron core of a planet that crashed billions of years ago.

Thousands of years ago, Willamette fell on our planet and was discovered only in 1902 by peaceful Americans in the form of a healing source of the Clackamas Indians - Tomanovos.

Tomanovos now rests in the American Museum of Natural History in New York, but recently a tribe of Indians made a deal with the museum to keep the meteorite in place for as long as the Clackamas visit it for ceremonial purposes.

When this massive iron meteorite roared from the sky in February 1947, eyewitnesses said it was brighter than the sun. And when the explosion tore it apart, its fragments showered the ground over an area of ​​half a square kilometer in the Sikhote-Alin mountains in Siberia.

The entry into the atmosphere and the explosion was visible within two hundred kilometers. For years, meteorite hunters have scoured the area for the well-recognized metal bars, twisted and curled in interesting ways.

Small pieces of Sikhote-Alin are still sold.

Sulakoga meteorite

One autumn day in 1954, a 31-year-old Alabama housewife named Ann Hodges was dozing on the couch when a five-kilogram meteorite fell from the sky.

He broke through the roof and hit the woman in the thigh. Fortunately, Hodges escaped with a bruise, while the neighbors saw this grapefruit-sized rock as a fireball that cut through the sky. Hodges got her moment of fame, and later donated the meteorite to the Alabama Museum of Natural History.

In Germany, there was a precedent: the boy said that a meteorite also fell on him while going to school. A 14-year-old student said he saw a flash of light and was then hit by a pea-sized meteorite. Who knew pebbles could be so dangerous.

ALH 84001

ALH 84001 (let's call it Al for short) was discovered in Antarctica in 1984, 13,000 years after its arrival from Mars.

Yes, from Mars.

Al was born from the lava of a Martian volcano about four and a half billion years ago. 15 million years ago, he lay on the surface of Mars, and then another asteroid or meteorite released him, sending him to Earth, after which he landed on the Allan Hills in Antarctica.

Inside Al, there may be evidence of early Martian life in the form of fossilized algae or small amounts of bacteria.

Orgeil meteorite

The Orgueil meteorite burned through the atmosphere in May 1864, breaking into 20 pieces on its way to the French town of Orgueil. The fragments were soft enough to be cut with a knife, and very soon the remains of the meteorite were distributed to museums around the world.

Since then, the Orgeil meteorite has caused a lot of controversy, as scientists have long thought about where the organic material brought with it came from - what if this is evidence of extraterrestrial life? But in fact, although the meteorite itself was real, the signs of life were faked.

How? Some spores stuck together with coal dust. But it has already happened in our world.

Peekskill meteorite

In 1992, a meteorite crossed the sky over Kentucky and Pittsburgh in greenish flames and crashed into a parked car in Peekskill that was innocent.

It was a 1980 Chevy Malibu that had only received a massive dent and continued to travel the world like a meteorite survivor. And the meteorite was the most ordinary piece of iron the size of a bowling ball.

What was strange was the amount of attention given to the Peekskill meteorite. Due to the fact that he crossed the east coast, his path and trajectory were recorded on video and analyzed by scientists, but it turned out that this is the most common meteorite. It's a pity.

Murchison meteorite

The Murchison meteorite broke into hundreds of pieces when it fell in Australia in September 1969. The largest of the pieces weighed about 50 kg, the smallest - less than 200 grams.

It fell to the ground in a massive fireball followed by a misty tail before disintegrating. Fragments are still being studied.

It turned out that the meteorite contains a wide range of amino acids, the building blocks of life, so the interest in it from astrobiologists is obvious.

The Allende meteorite, which fell to Earth in 1969 in Mexico, broke up into hundreds of fragments in flight. Together they will weigh several tons. Fragments, of course, went to private collections.

Many of the black pebbles are coated with a glassy material that forms under the influence of high temperatures during passage through the atmosphere. The meteorite contains particles that may be older than our solar system, olivine, and even microscopic diamonds. published