Currently, there are many works devoted to what causes the asteroid hazard for earthlings, what it consists in, how it is revealed. Some scientists propose solutions that would minimize the risks posed by outer space and the bodies in it. For a simple layman, asteroids are often nothing more than shooting stars that you want to make wishes on, but sometimes a celestial body causes a large-scale catastrophe. What is it about?
Typical situation
If you turn to sources explaining whether the asteroid hazard is a myth or reality, you can find out that small bodies falling on the surface of our planet are usually either warm or hot, but they do not heat up. Such meteorites fly through the earth's atmosphere in a few seconds, and there is not enough time to warm up properly. There are also cases wherethe body, flying through the air layers, was covered with an ice crust. This is due to the fact that the core of the asteroid is very cold.
When a meteorite falls, the most commonly seen object is either black or black with a reddish tint. If the meteorite consists of iron, it is characterized by increased hardness. Such items were previously used to make tools. It was the only source of iron available to man in antiquity.
One of the reasons for the asteroid danger is a meteor shower. This term refers to a situation where several square kilometers are, as it were, under the bombardment of celestial bodies. Over the past three centuries, such rains have been recorded at least 60 times. In fact, this rain is the fall from the sky of numerous stones and pieces of iron, which are scattered over a large area. Heavenly bodies fall on houses, they can fall directly on a person. However, from practice it is known that this happens extremely rarely.
There are also big ones
Analyzing what the asteroid hazard is, it is necessary to clarify the risks associated with the fall of large celestial bodies. Such collisions leave traces that remain for a long time, potholes on the planetary surface - craters. Astronomers have discovered that there are impact craters on the surface of all celestial bodies in our system, which have a dense upper layer with a fairly high level of hardness. Mars is especially expressive in this regard.
Among all the celestial bodies that have fallen on the surface of our planet, it is especially knownten kilometers in diameter - it fell approximately 36 million years ago. It is believed that it was this natural disaster that caused the extinction of life that existed then on the planet. The dominant animal species at the time were dinosaurs, which could not survive due to climate change.
What is known from history?
For a long time people have known that stones can fall from the sky. Since ancient times, various scientists and thinkers have thought about the problem of asteroid-comet hazard. In the sources that have survived to this day, you can see the fixation of events that happened a very, very long time ago. Among the oldest, it is worth noting information reflecting the events of approximately 654 years before the beginning of the current era. Manuscripts of Chinese sages tell about the bodies falling from the sky at that time.
You can learn about meteor showers from the sacred biblical texts, the writings of Plutarch, Livy. Even more ancient sources have been found dating back to about the 15th century BC. Such ancient evidence has been preserved by the Chinese. And in 1492, for the first time, French chroniclers reliably recorded the fall of a large celestial body. The event happened near the village of Ensisheim.
In the Slavic chronicles one can see blocks also devoted to observing the fall of celestial bodies. They first appeared in sources dated 1091. The next mention belongs to 1290. There were later mentions.
On average, until the 18th century, the scientific community denied the relevance of the asteroid hazard, believing that large bodies would fall from the skythey just can't. All stories about such events were recognized as nothing more than fiction, and prominent minds of that time were skeptical about any news on this topic. The situation changed in 1803, when a meteor shower fell on French lands on an area not exceeding 4 km in width and 11 in length.
During this event, numerous fragments fell on the ground - more than three thousand elements were counted in total. This fact is considered the first that scientists officially recognized. Since then, there has been a new research direction - meteoritics. At first, it was handled by Bio, Chladni, Arago.
New age - new approaches
The nineteenth century marked the development of new science. Its progress was accompanied by the emergence of another discipline. The new direction was called the theory of catastrophes caused by the fall of celestial bodies onto the planetary surface. However, at that moment, scientists had no idea about the asteroid-comet danger, so they did not support the initiators. For about a century and a half, this discipline of catastrophes staunchly fought for life, with a limited number of followers, and was not recognized by the scientific community at the world level.
The situation changed in the middle of the last century. Today, only in our country there are several major institutions dealing with the risks associated with space bodies, as well as possible measures to prevent damage. There are such universities and institutes in the capital region, in Novosibirsk and St. Petersburg.
Should we talk about the asteroid-space danger, if most of the bodies, as can be learned from old sources, fell on the planet almost unnoticed by the public? Some time ago, they organized an official collection of information about space objects that fell on our planet. Of particular interest is the data on the fall of bodies in early December 1922 near the village of Tsarev. The total area covered by the meteor shower is estimated at 15 km2.
In 1979, about 80 fragments were found here, weighing a total of 1.6 tons. The largest stone meteorite weighed 284 kg. Until recently, it was the largest meteorite in the entire territory of our country. Some time later, a more terrible catastrophe occurred near Chelyabinsk. The largest fragment of a meteorite that fell near the city weighed 570 kg.
Save everything
Despite the lack of understanding of the asteroid hazard as a global problem, for a long time people have already begun to collect meteorites, which they later managed to study. Unique samples have been collected since 1749. However, it is known that even 1,2 thousand years before the beginning of the current era, heavenly shrines, that is, meteorites, were preserved in the temple of Arcadia. Today, only GEOKHI has approximately 180 specimens found on the territory of our country, and another 500 obtained from foreign sources. There are more than 16,000 samples in total. Among them there are representatives of almost any type. In total, there are samples from 45 powers. The collection weighs over three dozen tons.
The largest found on ourmeteorite was discovered on the planet in 1920. It was found in Namibian lands near the village of Grootfontein. The celestial body was given the name Western Goba. It is an iron formation weighing 60 tons. Its dimensions in meters are almost three by three. From above, the asteroid is even, smooth, so it somewhat resembles a table. It only slightly protrudes above the earth's surface. From below, this object is relatively uneven. It is deepened into the earth's surface by about a meter.
Several more objects are known, the weight of which exceeds ten tons. There is information about this in Mauritania. It is believed to be located somewhere in Addara. Sources point to an iron meteorite weighing a hundred thousand tons and measuring approximately 10045 m.
Dangers
The three major events of the last century testify to the problem of asteroid danger. On the last day of June 1908, at about seven in the morning local time, the Tunguska meteorite fell. 22 years later, on August 13, 1930, a heavenly attack hit the Amazon. Astronomers from England saw three huge celestial bodies that fell somewhere near this river. As established a little later, the event happened near the Brazilian-Peruvian border. The force of the fall was compared to the power of a hydrogen bomb; it was three times higher than the previous mentioned meteorite. This natural disaster caused the death of several thousand people. As eyewitnesses later said, at about eight in the morning, the shade of the star suddenly changed to bloody, darkness covered everything around.
Nexta terrible event happened in 1947, on February 12. The fall occurred at the Sikhote-Alin section, it happened at about 11 o'clock. The zone was hit by a meteor shower. The inhabitants of Khabarovsk were able to see how a huge meteorite fell on the planet. It was later determined that he weighed several thousand kilograms. Friction caused the object to split even during the flight. One celestial body fell apart into many thousands, falling on the taiga lands like a hail of iron.
Study of the rocks showed more than a hundred sinkholes spread over an area larger than a couple of square kilometers. The diameter of the craters ranged from 2 to 26 m. The largest one was estimated to be six meters deep. In total, over the next half century, about 9 thousand small fragments and about three hundred large fragments were discovered. The largest weighed almost two tons, the smallest - only 0.18 g. The total mass of the collected was estimated at three dozen tons.
1990s
In short, the asteroid hazard is well illustrated by events recorded in the 90s of the last century. So, on May 17, 1990, a little more than half an hour before midnight, a celestial body made of iron suddenly fell. It happened in the Bashkir lands, on the field where the workers of the Sterlitamansky state farm grew bread. The largest part of this cosmic body was estimated at 315 kg. The fall was accompanied by a bright flash for a few seconds. The inhabitants of the area noted that they heard a roar and crackling. The sound was reminiscent of thunder accompanying a thunderstorm. The fall caused the appearance of a ten-meter deep crater half the diameter.
NextOn April 12, a meteorite fell in Sasovo. This event is recorded in the annals as having happened at 1 hour 34 minutes. The fall caused the appearance of a 28-meter funnel in the radius. The moment of impact was the cause of the instantaneous loss of 1800 tons of soil. All poles located near this place, set up to provide telegraph communications, were damaged - they leaned towards the center of the crater.
In 1992, a meteorite hit New York State. The event is dated October 9, at eight o'clock in the evening. The object was given the name "Pikskill". By this time, many knew (at least briefly) about the asteroid hazard, possible risks, and also about meteorites in general. It so happened that the fall of this particular celestial body gathered many eyewitnesses. Before reaching the earth's surface for about 40 km, the celestial body fell apart.
Counted 70 blocks. One of them hit a car near a residential building, breaking through the object. Later, when he was weighed, it turned out that he weighed 12.3 kg. It was about the size of a soccer ball. The chip was valued at $70,000.
Continuing the chronology
The next case, indicating the asteroid danger of small bodies in the solar system, is dated October 7, 1996. An asteroid fell in the village of Lyudinovo near Kaluga, the weight of which was then estimated at several tons. Flying, it seemed to the locals a huge ball of fire. The glow emanating from the body was comparable in brightness to that characteristic of the Moon in its maximum phase. Local residents noted a strong rumble, with which the asteroid attracted the attention of those who did not have timefall asleep (the event happened around 11 p.m.).
A year later, asteroids caught the attention of French residents. On the night of April 10, a celestial body fell on a passenger car, weighing which showed one and a half kilograms. The object was black, obviously burned, shaped like a baseball. Analysis of the composition showed bas alt. The flight itself attracted the attention of many, we managed to capture the event on a video camera.
In 1998, in a cotton field in Turkmenistan, near the village of Kunya-Ugrench, a meteorite fell, the weight of which was estimated at 820 kg. This event, which once again reminded of the asteroid danger of small bodies in the solar system, happened on June 20. The fall caused the appearance of a five-meter-deep crater. The width of the funnel is 3.5 m. The falling meteorite was a source of bright short-term glow and loud sounds. It is known that the roar produced by him was heard by people who were a hundred kilometers from the point of impact.
End of the decade
In 1999, an asteroid-comet hazard swept the capital region - a celestial body fell in the direction of Shcherbakovka in Moscow. In the same year, a fall was recorded in the Chechen lands.
In the millennium at nine in the morning on January 18, a meteorite fell in the northwestern Canadian lands. The celestial body was given the name Tagish Lake. According to local scientists, when the body just entered the atmosphere of our planet, it totaled from 55 to 200 tons, and was at least four meters in diameter, but possibly reached 15 m.
At the moment of entry into the atmosphere, the asteroid exploded, the explosive force was up to three kilotons of TNT. People who happened to observe the event with their own eyes later spoke about a bright flash, a strong bang, from which the ground shuddered, windows began to rattle, and the roofs shook off the snow cover. The information received from the sensors confirmed the explosion in the air. About a month later, fragments were found.
The place where the meteorite exploded was marked by a piece of debris weighing about 0.2 kg. The analysis showed carbonaceous chondrite, saturated with carbon compounds, including organic ones. Among all the celestial bodies that fell on our planet and then studied, only about 2% were formed by the same substance.
As can be inferred from the information provided, falls are more common at night than during the daytime.
Explosion in the air
Analyzing the asteroid-comet hazard, scientists have found that not every celestial body reaches the surface of our planet. If the dimensions of the object are less than a meter, it completely burns out during the passage of the air layer. If the size exceeds a meter, such an object can reach the planetary soil, partially burning down. It is believed that there are such celestial bodies that completely burn out before reaching the surface of 20-75 km. Many celestial bodies are known to have passed within a short distance of our planet.
In 1972 of the last century, an incident occurred that potentially indicated a colossal asteroid hazard of asteroids. A complex of random factors led to the fact that a celestial body fell into the atmosphere over Utah at a speed of about 15 km / s,the diameter of which was 80 m. It so happened that the trajectory turned out to be gentle, so the body flew about one and a half thousand kilometers, and somewhere above the Canadian lands it simply flew out of the earth's atmosphere, setting off on a further journey through space.
If such an object exploded, the force of the explosion would exceed the accompanying Tunguska meteorite - and it was estimated at 10-100 megatons. If the asteroid exploded, at least two thousand square kilometers would be affected.
Risks: so close
Asteroids and the asteroid hazard were discussed again in 1989. A kilometer-diameter asteroid flew between our planet and its satellite. Scientists discovered it when six hours had already passed after overcoming the area as close as possible to the planet. If the Earth were to pull this body, it would surely collapse on the ground, and the consequences would be catastrophic. Presumably, this would be accompanied by the appearance of a collar with a diameter of at least a dozen kilometers, or even a dozen and a half.
In 1991, at a distance of about 17,000 km from our planet, an asteroid swept by, the size of which is estimated at ten meters. Astronomers noticed this body when it was already moving away from the planet. The following year, a nine-meter asteroid moved between us and the earth's satellite, and in the 94th, a celestial body flared up in the earth's atmosphere, the weight of which was five thousand tons. This happened at a distance of about 20 km from the earth's surface. The celestial body burned down.
Another one flew in at a speed of 24 km / s, weighing from one to two tons. In the same year inat a distance of about 100,000 km from our planet, which is a quarter of the radius of the satellite's orbit, an asteroid flew by. This event happened on December 9th. The celestial body is known as 19994 XM. It was identified 14 hours before the approach to the planet.
Collision results
To fully understand the asteroid danger, you need to know what causes the fall of celestial bodies. An exceptionally terrible consequence is, of course, human sacrifices. In 1996, Lewis published papers summarizing his paleontological research. He calculated that only during the existence of civilization, accompanied by the fixation of history in writing, the victims numbered in the thousands.
In total, 123 events were investigated that caused injuries, injuries, and deaths. Of course, buildings were also harmed - and this was only for a couple of centuries. If we turn to biblical tests, we can see the story of the destruction of Sodom and Gomorrah. In the Koran, the 105th sura tells about the death of people due to asteroids. The blocks of the Mahadharata, the works of Solon from Ancient Greece are devoted to the same. The book “Chilam Balam” has come down to us, which tells about the victims of meteorites. It was compiled by the sages of the Mayan people.
In 1950, Fedinsky took up this topic, six years later the work of Schultz saw the light. They both studied the asteroid hazard and the damage and consequences associated with it. They found that over the last half of the millennium there is official information about 27 cases of hitting celestial bodies in buildings. At least 15 timesasteroids hit the roads. Two cases are described when objects hit cars.
In 1021, a meteorite fell on African lands, which caused the death of many people. In 1650, the monk died from being hit by a fragment of no more than eight grams in weight. It happened in Italy, in a monastery. In 1749, people on the ship were wounded. Recorded cases of wounds due to celestial bodies in 1827, 1881, 1954. On the territory of our country, such cases date back to 1914 and 1925.
Climate and more
Asteroid hazard is associated with possible climate change. To many ordinary people, the fall of a large celestial body seems to be the source of a terrible cataclysm that happens when an object falls to the ground. However, tsunamis and explosions are not the only danger. There is a risk of "nuclear winter", saturation of the atmosphere with nitrogen oxides. In the future, this provokes acid precipitation, a decrease in the concentration of compounds designed to protect the soil and water of the planet from aggressive solar radiation. This can cause a phenomenon known in science as "ultraviolet spring".
Asteroid hazard is manifested by the consequences associated with electric fields. When a celestial body enters the earth's layers, it can receive a certain charge. Suppose it was a comet no more than ten meters in diameter. Its power becomes comparable to a nuclear bomb. The speed developed by the celestial body reaches 70 km/s.
Is it possible to minimize risks
The current state of the art is such that effectivethere are no ways to protect against an asteroid hazard, especially in the case when a dangerous body is kilometers in diameter, since there are no ways to take an object away from the planet. The only thing that is possible is to take measures in order to minimize harm to the population. If a body is identified in a year or more, then there will be enough time to create shelters underground and above it, to form bases and supplies. There will be enough time to make protective equipment.
Presumably, in the near future, people will have sufficiently effective and accurate technologies to predict the fall of celestial bodies. As studies have shown, the "nuclear winter" due to the fall of a ten-kilometer celestial body, which has already happened once, lasted within a month. However, other effects, including a violation of the chemical composition of the atmosphere, may persist for a longer period.
