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.
>>3. FLIGHT OF METEORS IN THE EARTH’S ATMOSPHERE
Meteors appear at altitudes of 130 km and below and usually disappear around 75 km altitude. These boundaries change depending on the mass and speed of meteoroids penetrating the atmosphere. Visual determinations of the heights of meteors from two or more points (so-called corresponding) refer mainly to meteors of 0-3 magnitude. Taking into account the influence of rather significant errors, visual observations give the following values of meteor heights: appearance height H 1= 130-100 km, disappearance altitude H 2= 90 - 75 km, midway altitude H 0= 110 - 90 km (Fig. 8).
Rice. 8. Heights ( H) meteor phenomena. Height limits(left): the beginning and end of the fireball path ( B), meteors from visual observations ( M) and from radar observations ( RM), telescopic meteors according to visual observations ( T); (M T) - area of meteorite retention. Distribution curves(on right): 1 - the middle of the path of meteors according to radar observations, 2 - the same according to photographic data, 2a And 2b- the beginning and end of the path according to photographic data.
Much more accurate photographic height determinations usually refer to brighter meteors, from -5th to 2nd magnitude, or to the brightest parts of their trajectories. According to photographic observations in the USSR, the heights of bright meteors are within the following limits: H 1= 110-68 km, H 2= 100-55 km, H 0= 105-60 km. Radar observations make it possible to determine separately H 1 And H 2 only for the brightest meteors. According to radar data for these objects H 1= 115-100 km, H 2= 85-75 km. It should be noted that radar determination of the height of meteors applies only to that part of the meteor trajectory along which a sufficiently intense ionization trail is formed. Therefore, for the same meteor, the height according to photographic data may differ markedly from the height according to radar data.
For weaker meteors, using radar it is possible to statistically determine only their average height. The distribution of average heights of meteors predominantly of magnitude 1-6 obtained by radar is shown below:
Considering the factual material on determining the heights of meteors, it can be established that, according to all data, the vast majority of these objects are observed in the altitude zone of 110-80 km. In the same zone, telescopic meteors are observed, which, according to A.M. Bakharev have heights H 1= 100 km, H 2= 70 km. However, according to telescopic observations by I.S. Astapovich and his colleagues in Ashgabat, a significant number of telescopic meteors are also observed below 75 km, mainly at altitudes of 60-40 km. These are apparently slow and therefore faint meteors that begin to glow only after crashing deeply into the earth's atmosphere.
Moving on to very large objects, we find that fireballs appear at altitudes H 1= 135-90 km, having the height of the final point of the path H 2= 80-20 km. Fireballs penetrating into the atmosphere below 55 km are accompanied by sound effects, and those reaching an altitude of 25-20 km usually precede the fall of meteorites.
The heights of meteors depend not only on their mass, but also on their speed relative to the Earth, or the so-called geocentric speed. The higher the speed of the meteor, the higher it begins to glow, since a fast meteor, even in a rarefied atmosphere, collides with air particles much more often than a slow one. The average height of meteors depends on their geocentric speed as follows (Fig. 9):
| Geocentric speed ( Vg) | 20 | 30 | 40 | 50 | 60 | 70 km/sec |
| Average height ( H 0) | 68 | 77 | 82 | 85 | 87 | 90 km |
At the same geocentric speed of meteors, their heights depend on the mass of the meteor body. The greater the meteor's mass, the lower it penetrates.
The visible part of the meteor's trajectory, i.e. the length of its path in the atmosphere is determined by the heights of its appearance and disappearance, as well as the inclination of the trajectory to the horizon. The steeper the inclination of the trajectory to the horizon, the shorter the apparent length of the path. The path length of ordinary meteors, as a rule, does not exceed several tens of kilometers, but for very bright meteors and fireballs it reaches hundreds and sometimes thousands of kilometers.
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| Rice. 10. Zenith attraction of meteors. |
Meteors glow during a short visible segment of their trajectory in the earth's atmosphere, several tens of kilometers long, which they fly through in a few tenths of a second (less often in a few seconds). At this segment of the meteor’s trajectory, the effect of the Earth’s gravity and braking in the atmosphere is already manifested. When approaching the Earth, the initial speed of the meteor increases under the influence of gravity, and the path is curved so that its observed radiant shifts toward the zenith (zenith is the point above the observer’s head). Therefore, the effect of the Earth’s gravity on meteoroids is called zenith gravity (Fig. 10).
The slower the meteor, the greater the influence of zenith gravity, as can be seen from the following tablet, where V g denotes the initial geocentric speed, V" g- the same speed, distorted by the Earth’s gravity, and Δz- maximum value of zenith attraction:
| V g | 10 | 20 | 30 | 40 | 50 | 60 | 70 km/sec |
| V" g | 15,0 | 22,9 | 32,0 | 41,5 | 51,2 | 61,0 | 70.9 km/sec |
| Δz | 23 o | 8 o | 4 o | 2 o | 1 o | <1 o |
Penetrating into the Earth's atmosphere, the meteor body also experiences braking, almost imperceptible at first, but very significant at the end of the journey. According to Soviet and Czechoslovak photographic observations, braking can reach 30-100 km/sec 2 at the final segment of the trajectory, while along most of the trajectory braking ranges from 0 to 10 km/sec 2 . Slow meteors experience the greatest relative loss of velocity in the atmosphere.
The apparent geocentric velocity of meteors, distorted by zenith attraction and braking, is appropriately corrected to take into account the influence of these factors. For a long time, the speeds of meteors were not known accurately enough, since they were determined from low-precision visual observations.
The photographic method of determining the speed of meteors using a shutter is the most accurate. Without exception, all determinations of the speed of meteors obtained photographically in the USSR, Czechoslovakia and the USA show that meteoroid bodies must move around the Sun along closed elliptical paths (orbits). Thus, it turns out that the overwhelming majority of meteoric matter, if not all of it, belongs to the Solar System. This result is in excellent agreement with the data of radar determinations, although photographic results refer on average to brighter meteors, i.e. to larger meteoroids. The meteor velocity distribution curve found using radar observations (Fig. 11) shows that the geocentric speed of meteors lies mainly in the range from 15 to 70 km/s (a number of speed determinations exceeding 70 km/s are due to inevitable observational errors ). This once again confirms the conclusion that meteoroids move around the Sun in ellipses.
The fact is that the speed of the Earth's orbit is 30 km/sec. Therefore, oncoming meteors, having a geocentric speed of 70 km/sec, move relative to the Sun at a speed of 40 km/sec. But at the distance of the Earth, the parabolic speed (that is, the speed required for a body to be carried along a parabola outside the Solar System) is 42 km/sec. This means that all the speeds of meteors do not exceed parabolic speed and, therefore, their orbits are closed ellipses.
The kinetic energy of meteoroids entering the atmosphere with a very high initial speed is very high. Mutual collisions of molecules and atoms of the meteor and air intensively ionize gases in a large volume of space around the flying meteor body. Particles, torn out in abundance from the meteoric body, form around it a brightly glowing shell of hot vapor. The glow of these vapors resembles the glow of an electric arc. The atmosphere at the altitudes where meteors appear is very rarefied, so the process of reuniting electrons torn from atoms continues for quite a long time, causing a glow of a column of ionized gas, which lasts for several seconds and sometimes minutes. This is the nature of the self-luminous ionization trails that can be observed in the sky after many meteors. The glow spectrum of the trail also consists of lines of the same elements as the spectrum of the meteor itself, but neutral, not ionized. In addition, atmospheric gases also glow in the trails. This is indicated by those discovered in 1952-1953. in the spectra of the meteor trail there are lines of oxygen and nitrogen.
The spectra of meteors show that meteor particles consist either of iron, having a density of over 8 g/cm 3 , or are stone, which should correspond to a density of 2 to 4 g/cm 3 . The brightness and spectrum of meteors make it possible to estimate their size and mass. The apparent radius of the luminous shell of meteors of the 1st-3rd magnitude is estimated at approximately 1-10 cm. However, the radius of the luminous shell, determined by the scattering of luminous particles, far exceeds the radius of the meteoroid body itself. Meteor bodies flying into the atmosphere at a speed of 40-50 km/sec and creating the phenomenon of zero magnitude meteors have a radius of about 3 mm and a mass of about 1 g. The brightness of meteors is proportional to their mass, so the mass of a meteor of some magnitude is 2. 5 times less than for meteors of the previous magnitude. In addition, the brightness of meteors is proportional to the cube of their speed relative to the Earth.
Entering the Earth's atmosphere with a high initial speed, meteor particles are encountered at altitudes of 80 km or more in a very rarefied gas environment. The air density here is hundreds of millions of times less than at the surface of the Earth. Therefore, in this zone, the interaction of a meteoric body with the atmospheric environment is expressed in the bombardment of the body with individual molecules and atoms. These are molecules and atoms of oxygen and nitrogen, since the chemical composition of the atmosphere in the meteor zone is approximately the same as at sea level. During elastic collisions, atoms and molecules of atmospheric gases either bounce off or penetrate into the crystal lattice of the meteoric body. The latter quickly heats up, melts and evaporates. The rate of particle evaporation is at first insignificant, then increases to a maximum and decreases again towards the end of the visible path of the meteor. Evaporating atoms fly out of the meteor at speeds of several kilometers per second and, possessing high energy, experience frequent collisions with air atoms, leading to heating and ionization. A red-hot cloud of evaporated atoms forms the luminous shell of the meteor. Some atoms completely lose their outer electrons during collisions, resulting in the formation of a column of ionized gas with a large number of free electrons and positive ions around the meteor’s trajectory. The number of electrons in the ionized trail is 10 10 -10 12 per 1 cm of path. The initial kinetic energy is spent on heating, glowing and ionization in approximately the ratio of 10 6:10 4:1.
The deeper a meteor penetrates into the atmosphere, the denser its hot shell becomes. Like a very fast-flying projectile, the meteor forms a head shock wave; this wave accompanies the meteor as it moves in lower layers of the atmosphere, and in layers below 55 km causes sound phenomena.
The traces left after the flight of meteors can be observed both using radar and visually. You can especially successfully observe the ionization trails of meteors through high-aperture binoculars or telescopes (the so-called comet finders).
The tracks of fireballs penetrating into lower and dense layers of the atmosphere, on the contrary, mainly consist of dust particles and are therefore visible as dark smoky clouds against a blue sky. If such a dust trail is illuminated by the rays of the setting Sun or Moon, it can be visible as silvery streaks against the background of the night sky (Fig. 12). Such traces can be observed for hours until they are destroyed by air currents. The trails of less bright meteors, formed at altitudes of 75 km or more, contain only a very small fraction of dust particles and are visible solely due to the self-luminescence of atoms of ionized gas. The duration of visibility of the ionization trail with the naked eye is on average 120 seconds for fireballs of the -6th magnitude, and 0.1 seconds for a meteor of the 2nd magnitude, while the duration of the radio echo for the same objects (at a geocentric speed of 60 km/sec) is equal to 1000 and 0.5 sec. respectively. The extinction of ionization traces is partly due to the addition of free electrons to oxygen molecules (O 2) contained in the upper layers of the atmosphere.
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
The most well studied among the small bodies of the Solar System are asteroids - small planets. The history of their study goes back almost two centuries. Back in 1766, an empirical law was formulated that determined the average distance of a planet from the Sun depending on the serial number of this planet. In honor of the astronomers who formulated this law, it was named: “Titius-Bode law”. a = 0.3*2k + 0.4 where the number k = -* for Mercury, k = 0 for Venus, then k = n - 2 for Earth and Mars, k = n - 1 for Jupiter, Saturn and Uranus (n is the planet’s serial number from the sun).At first, astronomers, preserving the traditions of the ancients, assigned small planets the names of gods, both Greco-Roman and others. By the beginning of the twentieth century, the names of almost all gods known to mankind appeared in the sky - Greco-Roman, Slavic, Chinese, Scandinavian and even the gods of the Mayan people. Discoveries continued, there were not enough gods, and then the names of countries, cities, rivers and seas, the names and surnames of real living or living people began to appear in the sky. The question of streamlining the procedure for this astronomical canonization of names became inevitable. This question is all the more serious because, unlike the perpetuation of memory on Earth (names of streets, cities, etc.), the name of an asteroid cannot be changed. The International Astronomical Union (IAU) has been doing this since its creation (July 25, 1919). |
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The semimajor axes of the orbits of the main part of the asteroids range from 2.06 to 4.09 AU. e., and the average value is 2.77 a. e. The average eccentricity of the orbits of minor planets is 0.14, the average inclination of the asteroid’s orbital plane to the Earth’s orbital plane is 9.5 degrees. The speed of movement of asteroids around the Sun is about 20 km/s, the period of revolution (asteroid year) is from 3 to 9 years. The period of asteroids' own rotation (i.e., the length of a day on an asteroid) averages 7 hours.
Generally speaking, no main belt asteroid passes near the Earth's orbit. However, in 1932, the first asteroid was discovered whose orbit had a perihelion distance less than the radius of the Earth's orbit. In principle, its orbit allowed for the possibility of the asteroid approaching the Earth. This asteroid was soon "lost" and rediscovered in 1973. It was numbered 1862 and named Apollo. In 1936, the asteroid Adonis flew at a distance of 2 million km from the Earth, and in 1937, the asteroid Hermes flew at a distance of 750 thousand km from the Earth. Hermes has a diameter of almost 1.5 km, and was discovered only 3 months before its closest approach to the Earth. After the Hermes flyby, astronomers began to recognize the scientific problem of asteroid danger. To date, about 2,000 asteroids are known whose orbits allow them to approach Earth. Such asteroids are called near-Earth asteroids.
According to their physical characteristics, asteroids are divided into several groups, within which the objects have similar surface reflective properties. Such groups are called taxonomic (taxometric) classes or types. The table shows the 8 main main taxonomic types: C, S, M, E, R, Q, V and A. Each class of asteroids corresponds to meteorites that have similar optical properties. Therefore, each taxometric class can be characterized by analogy with the mineralogical composition of the corresponding meteorites.
The shape and size of these asteroids are determined using radar as they pass near the Earth. Some of them are similar to main belt asteroids, but most of them have a less regular shape. For example, the asteroid Toutatis consists of two, and maybe more, bodies in contact with each other.
Based on regular observations and calculations of asteroid orbits, the following conclusion can be drawn: there are so far no known asteroids that can be said to come close to Earth in the next hundred years. The closest will be the passage of the asteroid Hathor in 2086 at a distance of 883 thousand km.
To date, a number of asteroids have passed at distances significantly smaller than those given above. They were discovered during their closest passages. Thus, for now, the main danger is from yet undiscovered asteroids.
We have been prophesied many times about the End of the World according to the scenario that a meteorite, an asteroid will fall on Earth and smash everything to smithereens. But it did not fall, although small meteorites fell.
Could a meteorite still fall on Earth and destroy all life? What asteroids have already fallen on Earth and what consequences did this entail? Today we’ll talk about this.
By the way, the next End of the World is predicted for us in October 2017!!
Let's first understand what a meteorite, meteoroid, asteroid, comet is, at what speed they can hit the Earth, for what reason the trajectory of their fall is directed to the surface of the Earth, what destructive power meteorites carry, taking into account the speed of the object and mass.
Meteroid
“A meteoroid is a celestial body intermediate in size between cosmic dust and an asteroid.
A meteoroid flying into the Earth's atmosphere at great speed (11-72 km/s) heats up greatly due to friction and burns, turning into a luminous meteor (which can be seen as a “shooting star”) or a fireball. The visible trace of a meteoroid entering the Earth's atmosphere is called a meteor, and a meteoroid falling on the Earth's surface is called a meteorite."
Cosmic dust- small celestial bodies that burn in the atmosphere and are initially small in size.
Asteroid
“An asteroid (a common synonym until 2006 was a minor planet) is a relatively small celestial body of the Solar System moving in orbit around the Sun. Asteroids are significantly smaller in mass and size than planets, have an irregular shape and do not have an atmosphere, although they may also have satellites.”
Comet
“Comets are like asteroids, but they are not lumps, but frozen floating swamps. They mostly live at the edge of the solar system, forming the so-called Oort cloud, but some fly to the Sun. As they approach the Sun, they begin to melt and evaporate, forming behind them a beautiful tail glowing in the sun's rays. Among superstitious people they are considered harbingers of misfortune.”
Bolide- a bright meteor.
Meteor — “(Ancient Greek μετέωρος, “heavenly”), “shooting star” is a phenomenon that occurs when small meteoroids (for example, fragments of comets or asteroids) burn up in the Earth’s atmosphere.”
And finally, the meteorite:“A meteorite is a body of cosmic origin that fell on the surface of a large celestial object.
Most meteorites found have a mass of several grams to several kilograms (the largest meteorite found is Goba, which was estimated to weigh about 60 tons). It is believed that 5-6 tons of meteorites fall to the Earth per day, or 2 thousand tons per year.”
All relatively large celestial bodies that enter the Earth's atmosphere burn up before reaching the surface, and those that reach the surface are called meteorites.
Now think about the numbers: “5-6 tons of meteorites fall on the Earth per day, or 2 thousand tons per year”!!! Imagine, 5-6 tons, but we rarely hear reports that someone was killed by a meteorite, why?
Firstly, small meteorites fall, such that we don’t even notice, many fall on uninhabited lands, and secondly: cases of death from a meteorite strike are not excluded, type in a search engine, in addition, meteorites have repeatedly fallen near people, on dwellings (Tunguska bolide, Chelyabinsk meteorite, meteorite falling on people in India).
Every day over 4 billion cosmic bodies fall to Earth, This is the name given to everything that is larger than cosmic dust and smaller than an asteroid - this is what sources of information about the life of the Cosmos say. Basically, these are small stones that burn up in the layers of the atmosphere before reaching the earth's surface; a few pass this line; they are called meteorites, whose total weight per day is several tons. Meteoroids that do reach Earth are called meteorites.
A meteorite falls to Earth at a speed of 11 to 72 km per second, during the process of enormous speed the celestial body heats up and glows, which causes part of the meteorite to “blow”, reducing its mass, sometimes dissolving, especially at a speed of about 25 km per second or more . When approaching the surface of the planet, the surviving celestial bodies slow down their trajectory, falling vertically, and as a rule they cool down, which is why there are no hot asteroids. If a meteorite breaks apart along the “road,” a so-called meteor shower can occur, when many small particles fall to the ground.
At a low speed of the meteorite, for example a few hundred meters per second, the meteorite is able to retain the same mass. Meteorites are stony (chondrites (carbonaceous chondrites, ordinary chondrites, enstatite chondrites)
achondrites), iron (siderites) and iron-stone (pallasites, mesosiderites).
“The most common meteorites are stony meteorites (92.8% of falls).
The vast majority of stony meteorites (92.3% of stony meteorites, 85.7% of total falls) are chondrites. They are called chondrites because they contain chondrules - spherical or elliptical formations of predominantly silicate composition.”
Chondrites in the photo
Mostly meteorites are about 1 mm, maybe a little more... In general, smaller than a bullet... Perhaps there are a lot of them under our feet, perhaps they fell right before our eyes once, but we did not notice it.
So, what happens if a large meteorite falls to the Earth, does not crumble into stone rain, does not dissolve in the layers of the atmosphere?
How often does this happen and what are the consequences?
Fallen meteorites were discovered by finds or by falls.
For example, according to official statistics, the following number of meteorite falls was recorded:
in 1950-59 - 61, on average 6.1 meteorite falls per year,
in 1960-69 - 66, on average 6.6 per year,
in 1970-79 - 61, average per year 6.1,
in 1980-89 - 57, average per year 5.7,
in 1990-99 - 60, on average 6.0 per year,
in 2000-09 - 72, average per year 7.2,
in 2010-16 - 48, on average 6.8 per year.
As we can see even from official data, the number of meteorite falls has been increasing in recent years and decades. But, naturally, we don’t mean 1mm-thick celestial bodies...
Meteorites weighing from several grams to several kilograms fell to Earth in countless quantities. But there were not so many meteorites weighing more than a ton:
The Sikhote-Alin meteorite weighing 23 tons fell to the ground on February 12, 1947 in Russia, in the Primorsky Territory (classification - Zhelezny, IIAB),
Girin - a meteorite weighing 4 tons fell to the ground on March 8, 1976 in China, in the province of Girin (classification - H5 No. 59, chondrite),
Allende - a meteorite weighing 2 tons fell to the ground on February 8, 1969 in Mexico, Chihuahua (classification CV3, chondrite),
Kunya-Urgench - a meteorite weighing 1.1 tons fell to the ground on June 20, 1998 in Turkmenistan, in the city in the North-East of Turkmenistan - Tashauz (classification - chondrite, H5 No. 83),
Norton County - a meteorite weighing 1.1 tons fell to the ground on February 18, 1948 in the USA, Kansas (Aubrit classification),
Chelyabinsk - a meteorite weighing 1 ton fell to the ground on February 15, 2013 in Russia, in the Chelyabinsk region (chondrite classification, LL5 No. 102†).
Of course, the closest and most understandable meteorite to us is the Chelyabinsk meteorite. What happened when the meteorite fell? A series of shock waves during the destruction of a meteorite over the Chelyabinsk region and Kazakhstan, the largest of the fragments weighing about 654 kg was raised from the bottom of Lake Chebarkul in October 2016.
On February 15, 2013, at approximately 9:20 a.m., fragments of a small asteroid collided with the earth’s surface, which collapsed as a result of braking in the Earth’s atmosphere; the largest fragment weighed 654 kg; it fell into Lake Chebarkul. The superbolide collapsed in the vicinity of Chelyabinsk at an altitude of 15-25 km, the bright glow from the burning of the asteroid in the atmosphere was noticed by many residents of the city, someone even decided that the plane had crashed or a bomb had fallen, this was the main version of the media in the first hours. The largest meteorite known after the Tunguska meteorite. The amount of released energy, according to experts, ranged from 100 to 44 kilotons of TNT equivalent.
According to official data, 1,613 people were injured, mainly from broken glass from houses damaged by the explosion, about 100 people were hospitalized, two ended up in intensive care, the total amount of damage caused to buildings was about 1 billion rubles.
The Chelyabinsk meteoroid, according to NASA's preliminary estimates, was 15 meters in size and weighed 7,000 tons - these are its data before entering the Earth's atmosphere.
Important factors for assessing the potential danger of meteorites to the earth are the speed with which they approach the earth, their mass, and composition. On the one hand, the speed can destroy the asteroid into small fragments even before the earth’s atmosphere, on the other hand, it can give a powerful blow if the meteorite still reaches the ground. If an asteroid flies with less force, the probability of its mass being preserved is greater, but the force of its impact will not be so terrible. It is the combination of factors that is dangerous: the conservation of mass at the highest speed of the meteorite.
For example, a meteorite weighing more than a hundred tons hitting the ground at the speed of light can cause irreparable destruction.
Information from the documentary.
If you launch a round diamond ball with a diameter of 30 meters towards the Earth at a speed of 3 thousand km per second, then the air will begin to participate in nuclear fusion and, under the heating of the plasma, this process can destroy the diamond sphere even before it reaches the surface of the Earth: information from scientific films, according to scientists' projects. However, the chances that the diamond ball, even if broken, will reach the Earth are great; during the impact, a thousand times more energy will be released than from the most powerful nuclear weapon, and after that the area in the area of the fall will be empty, the crater will be large, but the Earth has seen more. This is at 0.01 of the speed of light.
What will happen if you accelerate the sphere to 0.99% of the speed of light? Superatomic energy will begin to operate, the diamond ball will become just a collection of carbon atoms, the sphere will flatten into a pancake, each atom in the ball will carry 70 billion volts of energy, it passes through the air, air molecules pierce through the center of the ball, then get stuck inside, it expands and reaches the Earth with a greater content of matter than at the beginning of the journey, when it crashes into the surface, it will pierce the Earth crooked and wide, creating a cone-shaped road through the root rock. The energy of the collision will tear a hole in the Earth's crust and explode into a crater so large that the molten mantle can be seen through it, an impact comparable to the 50 impacts of the Chicxulub asteroid, which killed the dinosaurs in the BC era. It is quite possible the end of all life on Earth, or at least the extinction of all people.
What will happen if we add more speed to our diamond sphere? Up to 0.9999999% of the speed of light? Now each carbon molecule carries 25 trillion wills of energy (!!!), which is comparable to the particles inside the large hadron collider, all of this will hit our planet with approximately the kinetic energy of the Moon moving in orbit, this is enough to punch a huge hole in the mantle and shake the earth's surface of the planet so that it simply melts, this with a 99.99% probability will put an end to all life on Earth.
Let's add more speed to the diamond ball up to 0.99999999999999999999951% of the speed of light, This is the highest speed of an object with mass ever recorded by man. Particle “Oh my God!”
The Oh-My-God particle is a cosmic shower caused by ultra-high energy cosmic rays, discovered on the evening of October 15, 1991 at the Dugway Proving Ground in Utah using the Fly's Eye Cosmic Ray Detector. "(English) owned by the University of Utah. The energy of the particle that caused the shower was estimated to be 3 × 1020 eV (3 × 108 TeV), about 20 million times greater than the energy of particles emitted by extragalactic objects, in other words, the atomic nucleus had a kinetic energy equivalent to 48 joules.
This is the energy of a 142-gram baseball moving at a speed of 93.6 kilometers per hour.
The Oh-My-God particle had such high kinetic energy that it moved through space at approximately 99.99999999999999999999951% of the speed of light."
This proton from Space, which “lit up” the atmosphere over Utah in 1991 and moved almost at the speed of light, the cascade of particles that were formed from its movement could not be reproduced even by the LHC (collider), such phenomena are detected several times a year and no one doesn't understand what it is. It seems to be coming from a galaxy-wide explosion, but what happened to cause these particles to come to Earth in such a hurry and why they did not slow down remains a mystery.
And if the diamond ball moves at the speed of the “Oh, my God!” particle, then nothing will help and no computer technology will simulate the development of events in advance; this plot is a godsend for dreamers and blockbuster creators.
But the picture will look something like this: a diamond ball rushes through the atmosphere, not noticing it and disappearing into the earth's crust, a cloud of expanding plasma with radiation diverges from the entry point, while energy pulsates outward through the body of the planet, as a result the planet becomes heated, begins to glow, the Earth will be knocked out into another orbit Naturally, all living things will die.
Taking into account the picture of the fall of the Chelyabinsk meteorite, which we recently observed, the scenarios of the fall of meteorites (diamond balls) from the film presented in the article, the plots of science fiction films - we can assume that:
- the fall of a meteorite, despite all the assurances of scientists that it is realistic to predict the fall of a large celestial body to Earth in decades, taking into account the achievements in the field of astronautics, cosmonautics, astronomy - in some cases it is impossible to predict!! And the proof of this is the Chelyabinsk meteorite, which no one predicted. And the proof of this is the particle “Oh, my God!” with their protons over Utah in '91... As they say, we don’t know what hour or day the end will come. However, humanity has been living and living for several thousand years now...
- first of all, we should expect small meteorites, and the destruction will be similar to that of the Chelyabinsk meteorite: glass will burst, buildings will be destroyed, perhaps part of the area will be scorched...
One should hardly expect terrible consequences as with the supposed death of dinosaurs, but cannot exclude them either.
- it is impossible to protect yourself from the forces of Space, unfortunately, meteorites make it clear to us that we are only small people on a small planet in a vast Universe, therefore it is impossible to predict the outcome, the time of contact of an asteroid with the earth, piercing the atmosphere more and more actively every year, Space seems to be claiming to our territory. Get ready or don’t get ready, but if the forces of heaven send an asteroid to our Earth, there’s no corner you can hide in…. So meteorites are also sources of deep philosophy and rethinking of life.
And here's another news!! We have just recently been prophesied about another End of the World!!! October 12, 2017, that is, we have very little time left. Presumably. A huge asteroid is rushing towards Earth!! This information is all over the news, but we are so used to such cries that we don’t react... what if...
According to scientists, the Earth already has holes and cracks, it is burning at the seams... If an asteroid reaches it, and a huge one, as predicted, it simply will not survive. You can only be saved by being in a bunker.
Wait and see.
There are opinions of psychologists that such intimidation is an attempt by any means to instill fear in humanity and control it in this way. The asteroid is indeed planning to pass by the Earth soon, but it will pass very far, there is a one in a million chance that it will hit the Earth.