Silent aliens from outer space - meteorites - flying to us from the stellar abyss and falling to Earth can have any size, from small pebbles to gigantic blocks. The consequences of such falls vary. Some meteorites leave behind vivid memories in our memory and a barely noticeable trace on the surface of the planet. Others, on the contrary, falling on our planet, entail catastrophic consequences.
The crash sites of the largest meteorites in the history of the Earth clearly demonstrate the true size of the uninvited guests. The surface of the planet has preserved huge craters and destruction left after encounters with meteorites, which indicates the possible disastrous consequences that await humanity if a large cosmic body falls to Earth.
Meteorites that fell on our planet
Space is not as deserted as it seems at first glance. According to scientists, 5-6 tons of space material fall on our planet every day. Over the course of a year, this figure is about 2,000 tons. This process occurs continuously, over billions of years. Our planet is constantly attacked by dozens of meteor showers, in addition, from time to time asteroids can fly towards the Earth, sweeping dangerously close to it.
Each of us can witness a meteorite fall at any moment. Some fall in front of us. In this case, the fall is accompanied by a whole series of bright and memorable phenomena. Other meteorites that we don't see fall in an unknown location. We learn about their existence only after we find fragments of material of extraterrestrial origin in the process of our life activity. In view of this, it is customary to divide space gifts that arrived at us at different times into two types:
- fallen meteorites;
- found meteorites.
Each fallen meteorite whose flight was predicted is given a name before falling. Found meteorites are named mainly by the place where they were found.
Information about how meteorites fell and what consequences arose is extremely limited. It was only in the middle of the 19th century that the scientific community began to track meteorite falls. The entire previous period in human history contains negligible facts about the fall of large celestial bodies to Earth. Such cases in the history of various civilizations are rather mythological in nature, and their description has nothing to do with scientific facts. In the modern era, scientists began to study the results of the fall of meteorites closest to us in time.
A huge role in the process of studying these astronomical phenomena is played by meteorites found on the surface of our planet in a later period. Today, a detailed map of meteorite falls has been compiled, identifying the areas where meteorites are most likely to fall in the future.
The nature and behavior of falling meteorites
Most of the celestial guests who visited our planet at different times are stone, iron and combined meteorites (iron-stone). The former are the most common occurrence in nature. These are residual fragments from which the planets of the Solar System were once formed. Iron meteorites are composed of naturally occurring iron and nickel, with the proportion of iron being more than 90%. The number of iron space guests that reached the surface layer of the earth's crust does not exceed 5-6% of the total.
Goba is by far the largest meteorite found on Earth. A huge block of extraterrestrial origin, an iron giant weighing 60 tons, fell to Earth in prehistoric times, and was found only in 1920. This space object has become known today only due to the fact that it consists of iron.
Stone meteorites are not such durable formations, but they can also reach large sizes. Most often, such bodies are destroyed during flight and upon contact with the ground, leaving behind huge craters and craters. Sometimes a stone meteorite is destroyed during its flight through the dense layers of the Earth's atmosphere, causing a powerful explosion.
This phenomenon is still fresh in the memory of the scientific community. The collision of planet Earth in 1908 with an unknown celestial body was accompanied by an explosion of colossal force that occurred at an altitude of about ten kilometers. This event took place in Eastern Siberia, in the basin of the Podkamennaya Tunguska River. According to the calculations of astrophysicists, the explosion of the Tunguska meteorite in 1908 had a power of 10-40 Mt in terms of TNT equivalent. In this case, the shock wave circled the globe four times. For several days, strange phenomena occurred in the sky from the Atlantic to the Far East. It would be more correct to call this object the Tunguska meteoroid, since the cosmic body exploded above the surface of the planet. Research into the explosion area, which has been going on for more than 100 years, has given scientists a huge amount of unique scientific and applied material. The explosion of such a large celestial body, weighing hundreds of tons in the area of the Siberian river Podkamennaya Tunguska, is called the Tunguska phenomenon in the scientific world. To date, more than 2 thousand fragments of the Tunguska meteorite have been found.
Another space giant left behind the huge Chicxulub crater, located on the Yucatan Peninsula (Mexico). The diameter of this giant depression is 180 km. The meteorite that left behind such a huge crater could have a mass of several hundred tons. It is not for nothing that scientists consider this meteorite to be the largest of all those that visited the Earth in its entire long history. No less impressive is the trace of a meteorite fall in the United States, the world-famous Arizona crater. Perhaps the fall of such a huge meteorite marked the beginning of the end of the era of dinosaurs.
Such destruction and such large-scale consequences are a consequence of the enormous speed of the meteorite rushing towards the Earth, its mass and size. A falling meteorite, whose speed is 10-20 kilometers per second and whose mass is tens of tons, is capable of causing colossal destruction and casualties.
Even smaller space guests that reach us can cause local destruction and cause panic among the civilian population. In the new era, humanity has repeatedly encountered such astronomical phenomena. In fact, everything except panic and excitement was limited to curious astronomical observations and subsequent study of meteorite fall sites. This happened in 2012 during the visit and subsequent fall of a meteorite with the beautiful name Sutter Mill, which, according to preliminary data, was ready to shred the territory of the United States and Canada. In several states at once, residents observed a bright flash in the sky. The subsequent flight of the fireball was limited to the fall on the earth's surface of a large number of small fragments scattered over a vast area. A similar meteor shower occurred in China and was observed throughout the world in February 2012. In the desert regions of China, up to hundreds of meteorite stones of various sizes fell, leaving pits and craters of various sizes after the collision. The mass of the largest fragment found by Chinese scientists was 12 kg.
Such astrophysical phenomena occur regularly. This is due to the fact that meteor showers rushing through our solar system can from time to time cross the orbit of our planet. A striking example of such meetings are the regular meetings of the Earth with the Leonid meteor shower. Among the known meteor showers, it is the Leonids that the Earth is forced to encounter every 33 years. During this period, which falls according to the calendar in the month of November, the meteor shower is accompanied by the falling of debris to the Earth.
Our time and new facts about fallen meteorites
The second half of the 20th century became a real testing and experimental ground for astrophysicists and geologists. During this time, there were quite a lot of meteorite falls, which were recorded in various ways. Some celestial guests with their appearance created a sensation among scientists and caused considerable excitement among ordinary people; other meteorites became just another statistical fact.
Human civilization continues to be incredibly lucky. The largest meteorites that fell to Earth in the modern era were neither enormous in size nor caused serious damage to infrastructure. Space aliens continue to fall in sparsely populated areas of the planet, showering some of the debris. Cases of meteorite falls resulting in casualties are practically absent from official statistics. The only facts of such an unpleasant acquaintance are the fall of a meteorite in Alabama in 1954 and the visit of a space guest to the UK in 2004.
All other cases of collision of the Earth with celestial objects can be characterized as an interesting astronomical phenomenon. The most famous facts of meteorite falls can be counted on one hand. There is a lot of documentary evidence about these phenomena and a huge amount of scientific work has been carried out:
- the Kirin meteorite, whose mass is 1.7 tons, fell in March 1976 in the northeastern part of China during a meteor shower that lasted 37 minutes and covered the entire northeastern part of the country;
- in 1990, near the city of Sterlitamak, on the May night from the 17th to the 18th, a meteorite stone weighing 300 kg fell. The heavenly guest left behind a crater with a diameter of 10 meters;
- In 1998, a meteorite weighing 800 kg fell in Turkmenistan.
The beginning of the third millennium was marked by a number of striking astronomical phenomena, among which the following are especially worth noting:
- September 2002 was marked by a monstrous air explosion in the Irkutsk region, which was the result of the fall of a huge meteorite;
- a meteorite that fell on September 15, 2007 in the area of Lake Titicaca. This meteorite fell into Peru, leaving behind a crater 6 meters deep. The fragments of this Peruvian meteorite found by local residents had sizes in the range of 5-15 cm.
In Russia, the most striking case is associated with the flight and subsequent fall of a celestial guest near the city of Chelyabinsk. On the morning of February 13, 2013, news spread across the country: a meteorite fell in the area of Lake Chebarkul (Chelyabinsk region). The main force of the impact of the cosmic body was experienced by the surface of the lake, from which meteorite fragments with a total weight of more than half a ton were subsequently caught from a depth of 12 meters. A year later, the largest fragment of the Chebarkul meteorite, weighing several tons, was caught from the bottom of the lake. At the time of the meteorite's flight, it was observed by residents of three regions of the country. Eyewitnesses observed a huge fireball over the Sverdlovsk and Tyumen regions. In Chelyabinsk itself, the fall was accompanied by minor destruction of city infrastructure, but there were cases of injuries among the civilian population.
Finally
It is impossible to say exactly how many more meteorites will fall on our planet. Scientists are constantly working in the field of ensuring anti-meteorite safety. An analysis of recent phenomena in this area has shown that the intensity of visits to Earth by space guests has increased. Predicting falls in the future is one of the main programs carried out by specialists from NASA, other space agencies and scientific astrophysical laboratories. Still, our planet remains poorly protected from visits from uninvited guests, and a large meteorite falling to Earth can do its job - put an end to our civilization.
If you have any questions, leave them in the comments below the article. We or our visitors will be happy to answer them
However, in space everything is different, some phenomena are simply inexplicable and cannot be subject to any laws in principle. For example, a satellite launched several years ago, or other objects will rotate in their orbit and will never fall. Why is this happening, At what speed does a rocket fly into space?? Physicists suggest that there is a centrifugal force that neutralizes the effect of gravity.
Having done a small experiment, we can understand and feel this ourselves, without leaving home. To do this, you need to take a thread and tie a small weight to one end, then unwind the thread in a circle. We will feel that the higher the speed, the clearer the trajectory of the load, and the more tension the thread will have; if we weaken the force, the speed of rotation of the object will decrease and the risk that the load will fall increases several times. With this little experience we will begin to develop our topic - speed in space.
It becomes clear that high speed allows any object to overcome the force of gravity. As for space objects, they each have their own speed, it is different. There are four main types of such speed and the smallest of them is the first. It is at this speed that the ship flies into Earth orbit.
In order to fly beyond its limits you need a second speed in space. At the third speed, gravity is completely overcome and you can fly out of the solar system. Fourth rocket speed in space will allow you to leave the galaxy itself, this is approximately 550 km/s. We have always been interested rocket speed in space km h, when entering orbit it is equal to 8 km/s, beyond it - 11 km/s, that is, developing its capabilities to 33,000 km/h. The rocket gradually increases speed, full acceleration begins from an altitude of 35 km. Speedspacewalk is 40,000 km/h.
Speed in space: record
Maximum speed in space- the record, set 46 years ago, still stands, it was achieved by astronauts who took part in the Apollo 10 mission. Having flown around the Moon, they returned back when speed of a spaceship in space was 39,897 km/h. In the near future, it is planned to send the Orion spacecraft into zero-gravity space, which will launch astronauts into low Earth orbit. Perhaps then it will be possible to break the 46-year-old record. Speed of light in space- 1 billion km/h. I wonder if we can cover such a distance with our maximum available speed of 40,000 km/h. Here what is the speed in space develops in the light, but we don’t feel it here.
Theoretically, a person can move at a speed slightly less than the speed of light. However, this will entail colossal harm, especially for an unprepared organism. After all, first you need to develop such a speed, make an effort to safely reduce it. Because rapid acceleration and deceleration can be fatal to a person.
In ancient times, it was believed that the Earth was motionless; no one was interested in the question of the speed of its rotation in orbit, because such concepts did not exist in principle. But even now it is difficult to give an unambiguous answer to the question, because the value is not the same in different geographical locations. Closer to the equator, the speed will be higher, in the region of southern Europe it is 1200 km/h, this is the average Earth's speed in space.
The previous post assessed the danger of an asteroid threat from space. And here we will consider what will happen if (when) a meteorite of one or another size does fall to Earth.
The scenario and consequences of such an event as the fall of a cosmic body to Earth, of course, depends on many factors. Let's list the main ones:
Size of cosmic body
This factor, naturally, is of primary importance. Armageddon on our planet can be caused by a meteorite 20 kilometers in size, so in this post we will consider scenarios for the fall of cosmic bodies on the planet ranging in size from a speck of dust to 15-20 km. There is no point in doing more, since in this case the scenario will be simple and obvious.
Compound
Small bodies of the Solar System can have different compositions and densities. Therefore, there is a difference whether a stone or iron meteorite falls to Earth, or a loose comet core consisting of ice and snow. Accordingly, in order to cause the same destruction, the comet nucleus must be two to three times larger than an asteroid fragment (at the same falling speed).
For reference: more than 90 percent of all meteorites are stone.
Speed
Also a very important factor when bodies collide. After all, here the transition of kinetic energy of motion into heat occurs. And the speed at which cosmic bodies enter the atmosphere can vary significantly (from approximately 12 km/s to 73 km/s, for comets - even more).
The slowest meteorites are those that catch up with the Earth or are overtaken by it. Accordingly, those flying towards us will add their speed to the orbital speed of the Earth, pass through the atmosphere much faster, and the explosion from their impact on the surface will be many times more powerful.
Where will it fall
At sea or on land. It is difficult to say in which case the destruction will be greater, it will just be different.
A meteorite may fall on a nuclear weapons storage site or a nuclear power plant, then the environmental damage may be greater from radioactive contamination than from the meteorite impact (if it was relatively small).
Angle of incidence
Doesn't play a big role. At those enormous speeds at which a cosmic body crashes into a planet, it does not matter at what angle it will fall, since in any case the kinetic energy of movement will turn into thermal energy and be released in the form of an explosion. This energy does not depend on the angle of incidence, but only on mass and speed. Therefore, by the way, all craters (on the Moon, for example) have a circular shape, and there are no craters in the form of trenches drilled at an acute angle.
How do bodies of different diameters behave when falling to Earth?
Up to several centimeters
They completely burn up in the atmosphere, leaving a bright trail several tens of kilometers long (a well-known phenomenon called meteor). The largest of them reach altitudes of 40-60 km, but most of these “specks of dust” burn up at altitudes of more than 80 km. 
Mass phenomenon - within just 1 hour, millions (!!) of meteors flash in the atmosphere. But, taking into account the brightness of the flashes and the observer’s viewing radius, at night in one hour you can see from several to dozens of meteors (during meteor showers - more than a hundred). Over the course of a day, the mass of dust from meteors deposited on the surface of our planet is calculated in hundreds and even thousands of tons.
From centimeters to several meters
Fireballs- the brightest meteors, the brightness of which exceeds the brightness of the planet Venus. The flash may be accompanied by noise effects, including the sound of an explosion. After this, a trail of smoke remains in the sky.
Fragments of cosmic bodies of this size reach the surface of our planet. It happens like this:
At the same time, stone meteoroids, and especially ice ones, are usually crushed into fragments due to explosion and heating. Metal ones can withstand pressure and fall onto the surface entirely:
Iron meteorite "Goba" measuring about 3 meters, which fell "entirely" 80 thousand years ago on the territory of modern Namibia (Africa) If the speed of entry into the atmosphere was very high (oncoming trajectory), then such meteoroids have much less chance of reaching the surface, since the force of their friction with the atmosphere will be much greater. The number of fragments into which a meteoroid is fragmented can reach hundreds of thousands; the process of their fall is called meteor Rain.
Over the course of a day, several dozen small (about 100 grams) fragments of meteorites can fall to Earth in the form of cosmic fallout. Considering that most of them fall into the ocean, and in general, they are difficult to distinguish from ordinary stones, they are found quite rarely.
The number of times a meter-sized cosmic bodies enter our atmosphere is several times a year. If you are lucky and the fall of such a body is noticed, there is a chance to find decent fragments weighing hundreds of grams, or even kilograms.
17 meters - Chelyabinsk bolide
Supercar- this is what is sometimes called especially powerful meteoroid explosions, like the one that exploded in February 2013 over Chelyabinsk. The initial size of the body that then entered the atmosphere varies according to various expert estimates, on average it is estimated at 17 meters. Weight - about 10,000 tons. 
The object entered the Earth's atmosphere at a very acute angle (15-20°) at a speed of about 20 km/sec. It exploded half a minute later at an altitude of about 20 km. The power of the explosion was several hundred kilotons of TNT. This is 20 times more powerful than the Hiroshima bomb, but here the consequences were not so fatal because the explosion occurred at a high altitude and the energy was dispersed over a large area, largely away from populated areas.
Less than a tenth of the meteoroid's original mass reached Earth, that is, about a ton or less. The fragments were scattered over an area more than 100 km long and about 20 km wide. Many small fragments were found, several weighing kilograms, the largest piece weighing 650 kg was recovered from the bottom of Lake Chebarkul: 
Damage: Almost 5,000 buildings were damaged (mostly broken glass and frames), and about 1.5 thousand people were injured by glass fragments. 
A body of this size could easily reach the surface without breaking into fragments. This did not happen due to the too acute angle of entry, because before exploding, the meteoroid flew several hundred kilometers in the atmosphere. If the Chelyabinsk meteoroid had fallen vertically, then instead of an air shock wave breaking the glass, there would have been a powerful impact on the surface, resulting in a seismic shock, with the formation of a crater with a diameter of 200-300 meters. In this case, judge for yourself about the damage and number of victims; everything would depend on the location of the fall.
Concerning repetition rates similar events, then after the Tunguska meteorite of 1908, this is the largest celestial body to fall to Earth. That is, in one century we can expect one or several such guests from outer space.
Tens of meters - small asteroids
The children's toys are over, let's move on to more serious things.
If you read the previous post, then you know that small bodies of the solar system up to 30 meters in size are called meteoroids, more than 30 meters - asteroids.
If an asteroid, even the smallest one, meets the Earth, then it will definitely not fall apart in the atmosphere and its speed will not slow down to the speed of free fall, as happens with meteoroids. All the enormous energy of its movement will be released in the form of an explosion - that is, it will turn into thermal energy, which will melt the asteroid itself, and mechanical, which will create a crater, scatter earthly rock and fragments of the asteroid itself, and also create a seismic wave.
To quantify the scale of such a phenomenon, we can consider, for example, the asteroid crater in Arizona: 
This crater was formed 50 thousand years ago by the impact of an iron asteroid with a diameter of 50-60 meters. The force of the explosion was 8000 Hiroshima, the diameter of the crater was 1.2 km, the depth was 200 meters, the edges rose 40 meters above the surrounding surface.
Another event of comparable scale is the Tunguska meteorite. The power of the explosion was 3000 Hiroshima, but here there was a fall of a small comet nucleus with a diameter of tens to hundreds of meters, according to various estimates. Comet nuclei are often compared to dirty snow cakes, so in this case no crater appeared, the comet exploded in the air and evaporated, felling a forest over an area of 2 thousand square kilometers. If the same comet exploded over the center of modern Moscow, it would destroy all the houses right up to the ring road.
Drop Frequency asteroids tens of meters in size - once every few centuries, hundred-meter ones - once every several thousand years.
300 meters - asteroid Apophis (the most dangerous known at the moment)
Although, according to the latest NASA data, the probability of the Apophis asteroid hitting the Earth during its flight near our planet in 2029 and then in 2036 is practically zero, we will still consider the scenario of the consequences of its possible fall, since there are many asteroids that have not yet been discovered, and such an event can still happen, if not this time, then another time.
So... the asteroid Apophis, contrary to all forecasts, falls to Earth...
The power of the explosion is 15,000 Hiroshima atomic bombs. When it hits the mainland, an impact crater with a diameter of 4-5 km and a depth of 400-500 meters appears, the shock wave demolishes all brick buildings in an area with a radius of 50 km, less durable buildings, as well as trees falling at a distance of 100-150 kilometers from the place falls. A column of dust, similar to a mushroom from a nuclear explosion several kilometers high, rises into the sky, then the dust begins to spread in different directions, and within a few days it spreads evenly across the entire planet. 
But, despite the greatly exaggerated horror stories that the media usually scare people with, nuclear winter and the end of the world will not come - the caliber of Apophis is not enough for this. According to the experience of powerful volcanic eruptions that took place in the not very long history, during which huge emissions of dust and ash also occur into the atmosphere, with such an explosion power the effect of “nuclear winter” will be small - a drop in the average temperature on the planet by 1-2 degrees, after Six months or a year everything returns to its place.
That is, this is a catastrophe not on a global, but on a regional scale - if Apophis gets into a small country, he will destroy it completely.
If Apophis hits the ocean, coastal areas will be affected by the tsunami. The height of the tsunami will depend on the distance to the place of impact - the initial wave will have a height of about 500 meters, but if Apophis falls into the center of the ocean, then 10-20 meter waves will reach the shores, which is also quite a lot, and the storm will last with such mega-waves. there will be waves for several hours. If the impact in the ocean occurs not far from the coast, then surfers in coastal (and not only) cities will be able to ride such a wave: (sorry for the dark humor) 
Recurrence frequency events of similar magnitude in the history of the Earth are measured in tens of thousands of years.
Let's move on to global disasters...
1 kilometer
The scenario is the same as during the fall of Apophis, only the scale of the consequences is many times more serious and already reaches a low-threshold global catastrophe (the consequences are felt by all of humanity, but there is no threat of the death of civilization):
The power of the explosion in Hiroshima: 50,000, the size of the resulting crater when falling onto land: 15-20 km. Radius of the destruction zone from blast and seismic waves: up to 1000 km.
When falling into the ocean, again, everything depends on the distance to the shore, since the resulting waves will be very high (1-2 km), but not long, and such waves die out quite quickly. But in any case, the area of flooded territories will be huge - millions of square kilometers.
A decrease in the transparency of the atmosphere in this case from emissions of dust and ash (or water vapor when falling into the ocean) will be noticeable for several years. If you enter a seismically dangerous zone, the consequences may be aggravated by earthquakes provoked by an explosion.
However, an asteroid of such diameter will not be able to tilt the Earth’s axis noticeably or affect the rotation period of our planet.
Despite the not-so-dramatic nature of this scenario, this is a fairly ordinary event for the Earth, since it has already happened thousands of times throughout its existence. Average repetition frequency- once every 200-300 thousand years.
An asteroid with a diameter of 10 kilometers is a global catastrophe on a planetary scale
- Hiroshima explosion power: 50 million
- The size of the resulting crater when it falls on land: 70-100 km, depth - 5-6 km.
- The depth of cracking of the earth's crust will be tens of kilometers, that is, right up to the mantle (the thickness of the earth's crust under the plains is on average 35 km). Magma will begin to emerge to the surface.
- The area of the destruction zone can be several percent of the Earth's area.
- During the explosion, a cloud of dust and molten rock will rise to a height of tens of kilometers, possibly up to hundreds. The volume of ejected materials is several thousand cubic kilometers - this is enough for a light “asteroid autumn”, but not enough for an “asteroid winter” and the beginning of an ice age.
- Secondary craters and tsunamis from fragments and large pieces of ejected rock.
- A small, but by geological standards, decent tilt of the earth’s axis from the impact - up to 1/10 of a degree.
- When it hits the ocean, it results in a tsunami with kilometer-long (!!) waves that go far into the continents.
- In the event of intense eruptions of volcanic gases, acid rain is subsequently possible.
But this is not quite Armageddon yet! Our planet has already experienced even such enormous catastrophes dozens or even hundreds of times. On average this happens once once every 100 million years. If this happened at the present time, the number of victims would be unprecedented, in the worst case it could be measured in billions of people, and besides, it is unknown what kind of social upheaval this would lead to. However, despite the period of acid rain and several years of some cooling due to a decrease in the transparency of the atmosphere, in 10 years the climate and biosphere would have been completely restored.
Armageddon
For such a significant event in human history, an asteroid the size of 15-20 kilometers in quantity 1 piece.
The next ice age will come, most of the living organisms will die, but life on the planet will remain, although it will no longer be the same as before. As always, the strongest will survive...
Such events also happened repeatedly in the world. Since the emergence of life on it, Armageddons have happened at least several, and perhaps dozens of times. It is believed that the last time this happened was 65 million years ago ( Chicxulub meteorite), when dinosaurs and almost all other species of living organisms died, only 5% of the chosen ones remained, including our ancestors. 
Full Armageddon
If a cosmic body the size of the state of Texas crashes into our planet, as it happened in the famous film with Bruce Willis, then even bacteria will not survive (although, who knows?), Life will have to arise and evolve anew. 
Conclusion
I wanted to write a review post about meteorites, but it turned out to be an Armageddon scenario. Therefore, I want to say that all the events described, starting from Apophis (inclusive), are considered theoretically possible, since they will definitely not happen in the next hundred years at least. Why this is so is described in detail in the previous post.
I would also like to add that all the figures given here regarding the correspondence between the size of the meteorite and the consequences of its fall to Earth are very approximate. Data in different sources differ, plus the initial factors during the fall of an asteroid of the same diameter can vary greatly. For example, it is written everywhere that the size of the Chicxulub meteorite is 10 km, but in one, as it seemed to me, authoritative source, I read that a 10-kilometer stone could not have caused such troubles, so for me the Chicxulub meteorite entered the 15-20 kilometer category .
So, if suddenly Apophis still falls in the 29th or 36th year, and the radius of the affected area will be very different from what is written here - write, I’ll correct it
Space is a space filled with energy. The forces of nature force chaotically existing matter to group. Objects with a certain shape and structure are formed. Planets and their satellites have long been formed in the solar system, but this process does not end. A huge amount of matter: dust, gas, ice, stone and metal, fill space. These objects have a classification.
A body no larger than ten meters in size is called a meteoroid; a larger body can be considered an asteroid. A meteor is an object that burns up in the atmosphere and falls to the surface to become a meteorite.
Hundreds of thousands of asteroids have been discovered in the solar system. Some reach more than 500 kilometers in diameter. Large arrays take on a spherical shape and begin to be classified by scientists as dwarf planets. The speed of asteroids is limited by their presence in the solar system; they revolve around the sun. Pallas is currently considered the largest asteroid, 582x556x500 km. It has an average speed of 17 kilometers per second; the speed developed by asteroids does not exceed this value by more than two to three times. The name of the asteroids is the date of their discovery (1959 LM, 1997 VG). After studying and calculating the orbit, the object can receive its own name.
Celestial bodies inevitably collide with each other. The moon has preserved the result of millions and millions of years of interaction. Huge craters on the ground indicate that once upon a time there was global destruction. People always strive for control; all potential threats must have methods and technologies to eliminate them. The obvious option of using nuclear weapons is ineffective. Most of the explosion energy is simply dissipated in space. It is extremely important to detect a dangerous lump as early as possible, which is not always possible. The good thing is that the larger the body, the easier it is to detect.
Tons of cosmic dust fly into the atmosphere every day, and at night you can watch small meteoroids burn up as so-called “falling stars.” Every year, meteoroids up to several meters in size enter the airspace of our planet. The meteorite can enter the atmosphere at a speed of 100,000 km/h. At an altitude of several tens of kilometers, the speed drops sharply. In general, information about the speed of meteorites is blurry. They give limits from 11 to 72 kilometers per second for meteorites of the solar system; those arriving from outside develop an order of magnitude higher speed.
On February 15, 2013, a meteorite fell in the Chelyabinsk region. Presumably its diameter was from 10 to 20 meters. The speed of the meteorite is not precisely determined. The bright glow of the fireball was observed hundreds of kilometers from the epicenter. The car exploded at a high altitude. The video captures the moment of the flash, after 2 minutes. 22 sec. a shock wave arrives.
Meteorites are divided into stone and iron. The composition always includes a mixture of elements with various proportions. The structure may be heterogeneous with inclusions. A metal alloy of iron meteorites of excellent quality, suitable for the manufacture of all kinds of products.
The speed of a meteorite body that falls to Earth, flying from the distant depths of space, exceeds the second cosmic speed, whose value is eleven point two kilometers per second. This meteorite speed equal to that which must be imparted to the spacecraft in order to escape from the gravitational field, that is, this speed is acquired by the body due to the gravity of the planet. However, this is not the limit. Our planet moves in orbit at a speed of thirty kilometers per second. When a moving object of the Solar System crosses it, it can have a speed of up to forty-two kilometers per second, and if a celestial wanderer moves along an oncoming trajectory, that is, head-on, then it can collide with the Earth at a speed of up to seventy-two kilometers per second . When a meteorite body enters the upper layers of the atmosphere, it interacts with rarefied air, which does not greatly interfere with the flight, creating almost no resistance. In this place, the distance between the gas molecules is greater than the size of the meteorite itself and they do not interfere with the flight speed, even if the body is quite massive. In the same case, if the mass of a flying body is even slightly greater than the mass of a molecule, then it slows down already in the uppermost layers of the atmosphere and begins to settle under the influence of gravity. This is how about a hundred tons of cosmic matter settle on Earth in the form of dust, and only one percent of large bodies still reach the surface.
So, at an altitude of one hundred kilometers, a freely flying object begins to slow down under the influence of friction arising in the dense layers of the atmosphere. A flying object encounters strong air resistance. The Mach number (M) characterizes the motion of a solid body in a gaseous medium and is measured by the ratio of the speed of the body to the speed of sound in the gas. This M number for a meteorite constantly changes with altitude, but most often does not exceed fifty. A rapidly flying body forms an air cushion in front of it, and the compressed air leads to the appearance of a shock wave. The compressed and heated gas in the atmosphere heats up to a very high temperature and the surface of the meteorite begins to boil and splash, carrying away the molten and remaining solid material, that is, the process of abelation occurs. These particles glow brightly, and the phenomenon of a fireball occurs, leaving a bright trail behind it. The compression area that appears in front of a meteorite rushing at enormous speed diverges to the sides and at the same time a head wave is formed, similar to that which occurs from a ship walking on the lead. The resulting cone-shaped space forms a wave of vortex and rarefaction. All this leads to a loss of energy and causes increased deceleration of the body in the lower layers of the atmosphere.
It may happen that the speed of a is from eleven to twenty-two kilometers per second, its mass is not large, and it is mechanically strong enough, then it can slow down in the atmosphere. This ensures that such a body is not subject to abelation; it can reach the surface of the Earth almost unchanged.
As you descend further, the air slows down more and more. meteorite speed and at an altitude of ten to twenty kilometers from the surface it completely loses cosmic speed. The body seems to hang in the air, and this part of the long journey is called the delay region. The object gradually begins to cool down and stops glowing. Then everything that remains from the difficult flight falls vertically to the surface of the Earth under the force of gravity at a speed of fifty to one hundred and fifty meters per second. In this case, the force of gravity is compared with air resistance, and the heavenly messenger falls like an ordinary thrown stone. It is this meteorite speed that characterizes all objects that have fallen to Earth. At the impact site, as a rule, depressions of different sizes and shapes are formed, which depends on the weight of the meteorite and the speed with which it approached the soil surface. Therefore, by studying the crash site, we can say exactly what the approximate meteorite speed at the moment of collision with the Earth. The monstrous aerodynamic load gives the celestial bodies that come to us characteristic features by which they can be easily distinguished from ordinary stones. They form a melting crust, the shape is most often cone-shaped or melted-clastic, and the surface, as a result of high-temperature atmospheric erosion, receives a unique rhemhalyptian relief.