Meteorite hazard to the earth. The most potentially dangerous asteroids: is there a risk for earthlings? What does "dangerous asteroid" mean?
What are asteroids and comets? Where do they live? What danger do they pose? How likely is a meteorite to hit Earth in the near future?
I want to say right away that I did not set the goal of this article to scare the reader with scary stories about a cosmic threat with a colorful description of a comet falling to Earth and the death of all life. I think it is unlikely that anyone will be able to do it better than in the movie "Armageddon" in the near future. Here I simply collected and systematized in a popular form the basic information about the small bodies of the solar system and tried to objectively answer the question: “Is it possible to sleep peacefully at night or should we be afraid that at any moment a rock the size of a house or a whole city and destroy, if not half the planet, then some small country?
The world of asteroids and comets.
I have two news for you - good and bad. I'll start with the bad: around the Sun within a sphere with a radius of 1 light year (this is a sphere in which the Sun can hold small bodies with its gravity) constantly circle trillions(!!!) blocks ranging in size from tens of meters to hundreds and even thousands of kilometers!
The good news is that the solar system has been in existence for 4.5 billion years and the initial mess of cosmic matter has long been structured into a stable system of planets, asteroids, comets, etc., which we observe. The period of massive meteorite bombardments, which the Earth and other planets experienced, remained in the distant prehistoric past. Almost everything large that was supposed to fall to Earth from space, fortunately, has already fallen. Right now the situation in the solar system is generally calm. Occasionally, a comet will please with its appearance - a guest from the very outskirts of the possessions of our luminary.
All large asteroids have been discovered, rewritten, registered, their orbits have been calculated, they do not pose a danger.
It is more difficult with small ones - there are more of them in space than there are ants in all anthills. It is simply impossible to register every space rock. Due to their small size, they are found only in the immediate vicinity of the Earth. And very small ones are not detected at all before entering the atmosphere. But such ones do not bring much harm, at most - they can scare with a loud bang before almost completely burning out. Although the glass in houses can also be broken, as the very Chelyabinsk meteorite did, which demonstrated the reality of the threat from space.
The greatest concern is caused by asteroids larger than 150 meters. Theoretically, their number is only "main belt" may be in the millions. Finding such a body at a sufficiently large distance to have time to do something is very difficult. And a meteorite measuring 150-300 meters is guaranteed to destroy the city if it hits it.
Thus, the threat from space is more than real. Meteorites have been falling to Earth throughout its history, and sooner or later it will happen again. To assess the level of danger, I propose to understand in more detail the structure of this heavenly economy.
Terminology.
- Small bodies of the solar system- all natural objects revolving around the Sun, except for planets, dwarf planets and their satellites.
- dwarf planets- bodies with a mass sufficient to maintain a shape close to spherical (from 300-400 km) due to their own gravity, but not dominating in their orbit.
- — small bodies larger than 30 meters.
- Small bodies less than 30 meters in size are called meteoroids.
- Further, as the size decreases, go micrometeoroids(less than 1-2 mm), and then cosmic dust(particles smaller than 10 µm).
- Meteorite- what is left of an asteroid or meteoroid after it fell to Earth.
- fireball- a flash visible when a small body enters the atmosphere.
- Comet- an icy small body. As it approaches the Sun, the ice and frozen gas evaporates, forming the tail and coma (head of the comet).
- Aphelion is the farthest point of the orbit.
- Perihelion is the closest point in the orbit to the Sun.
- a.u.- Astronomical unit of distance, this is the distance from the Earth to the Sun (150 million km).
Place of mass concentration of small bodies. This is a wide band between the orbits of Mars and Jupiter, along which the main part of the asteroids of the central part of the solar system rotates:
Most of the small bodies of the solar system fly around the sun in groups in close orbits. This is due to the fact that over billions of years they experience gravitational effects from the planets (especially Jupiter) and gradually shift from unstable orbits, where such effects are maximum, to stable ones, where gravitational disturbances are minimal. Also, groups of asteroids arise during collisions, when a large asteroid falls apart into many small ones, or it remains intact, but many fragments break off from it. At the moment, dozens of groups (or families) of asteroids are known, but most of them belong to the main belt.
IN main belt 4 bodies larger than 400 km are known, about 200 bodies larger than 100 km, about 1000 larger than 15 km. Theoretically, it is estimated that there should be about 1-2 million asteroids larger than 1 km. Despite the huge number, the total mass of these stones is only 4% of the mass of the moon.
Previously, it was assumed that the main asteroid belt arose from the debris of the exploded planet Phaethon. But now a more likely version is that the planet in this area simply could not arise due to the proximity of the giant Jupiter.
The millions of asteroids in this belt, many of which could arrange Armageddon on Earth, do not pose a danger to us, since their orbits lie outside the orbit of Mars.
Collisions.
But sometimes they collide with each other, then some fragment can accidentally fall into the Earth. The probability of such an accident is extremely low. If you calculate it for a time period equal to the life of 2-3 generations, then these generations do not have to worry too much.
But the Earth has existed for billions of years, during which time everything has happened. For example, the extinction of about 80% of all life and 100% of dinosaurs 65 million years ago. It has been practically proven that this is to blame, the crater from which is located in the region of the Yucatan Peninsula (Mexico). Judging by the crater, it was a meteorite about 10 km in size. Presumably, it belonged to the Baptistina asteroid family, which was formed during the collision of a 170-km asteroid with another fairly large one.
How often do such collisions occur? I propose to turn on the spatial imagination and imagine the main asteroid belt reduced by 100 thousand times. On this scale, its width will become approximately equal to the width of the Atlantic Ocean. An asteroid with a diameter of 1 km will turn into a ball 1 cm in size. Four giant bodies - Ceres, Vesta, Pallas and Hygiea with sizes of 950, 530, 532 and 407 km, respectively, will become balls about 10, 5 and 4 meters in size. 100-meter asteroids (the minimum size that poses a sufficiently serious threat) will become 1 mm crumbs. Now let's mentally scatter them all over the Atlantic and imagine that they run smoothly in approximately one direction, for example, first from north to south, then back. Their trajectories are not exactly parallel - let some sail from London to the lower tip of South America, and others from New York to South Africa. Moreover, they complete their journey back and forth (orbital period) in 4-6 years (on such a scale, this approximately corresponds to a speed of 1 km / h).
Have you submitted this picture? On the same scale, the Earth in the closest position relative to any asteroid will be a 130-meter island in the Indian Ocean. What is the probability that two asteroids collided and the fragment landed right in it!? Now, I think you will sleep more peacefully. At the very least, the anxiety about cosmic Armageddon, constantly fueled by the media, should fade into the background. Even if several million balls ranging in size from 1 millimeter to tens of centimeters and only a few hundred more than a meter in size are poured into the Atlantic Ocean, with such a movement that we talked about, intuition suggests that collisions and fragments hitting the Earth in the near future can not be expected. And mathematical calculations give such data: asteroids with a size of 20 km or more hit each other once every 10 million years.
One of the typical pictures that are usually given as an illustration when describing the asteroid belt:
Now I think you understand that in real life it looks completely different. In fact, the ratio of distances between neighboring blocks and their sizes is much larger there than in this figure. It is measured in thousands of kilometers, sometimes hundreds, so interplanetary spacecraft have so far quietly flown through this belt without any complications.
However, despite all that has been said, it is from the Main Asteroid Belt that more than 99% of meteorite fragments found on Earth originate. They made a significant contribution to the "development" of life on Earth, periodically arranging mass extinctions of species on it. Well, that's why he is the Chief ..
Asteroids approaching the Earth.
As mentioned above, most asteroids belong to a family, that is, bodies of the same group fly in similar orbits. There are families of orbits which approach the Earth's orbit, or even cross it. The most dangerous of them are the families of Cupid, Apollo and Aten:
Amur group- the least threatening of these three, since it does not cross the Earth's orbit, but only approaches it. This is enough to pose a potential danger, since with such approaches, the Earth's gravity unpredictably changes the orbit of asteroids, and therefore the threat from a potential one can turn into a real one. Mars has the same effect on them, since they cross its orbit, therefore sometimes approaching it. About 4000 asteroids of this group are known, of course, most of them have not yet been discovered. The largest of them is Ganymede (not to be confused with the satellite of Jupiter), its diameter is 31.5 km. Another member of this group - Eros (34 X 11 km), is famous for the fact that for the first time in history a spacecraft landed on it - "NEAR Shoemaker" (NASA).
Apollo group. As can be seen in the diagram, the asteroids of this group, like the "cupids", at aphelion (the maximum distance from the Sun) go to the Main belt, and at perihelion they go inside the earth's orbit. That is, they cross it in two places. In this family, more than 5,000 members are known, mostly "trifle", the largest - 8.5 km.
Aten group. About 1,000 Atons are known (the largest is 3.5 km). They, on the contrary, ply inside the Earth's orbit, and only at aphelion go beyond its limits, also crossing our orbit.
In fact, the diagram shows the projections of the typical orbits of "Apollos" and "Atons". Each of the asteroids has a certain orbital inclination, so not every one of them crosses the Earth's orbit - most pass under or above it (or slightly to the side). But if it crosses, then there is a possibility that at some point the Earth will be at the same point with it - then a collision will occur.
This is how this space carousel turns from year to year. Astronomers around the world are watching every suspicious object, constantly discovering more and more. On the website of the "Center for Small Planets" I found a list of asteroids threatening the Earth (potentially dangerous). Asteroids in it are sorted starting from the most dangerous.
Apophis.
The orbit of the asteroid Apophis intersects the Earth's orbit in two places. "Apophis" - one of the "atones", leads the list of the most dangerous asteroids, since the estimated distance at which it will pass the Earth is the smallest of all known - only 30-35 thousand km from the surface of our planet. Since there is a possibility of an error in the calculations due to inaccurate data, there is also a certain probability of a “hit”.
Its diameter is about 320 meters, the period of revolution around the Sun is 324 Earth days. That is, once every 162 days it practically flies through the Earth's orbit, but since the total length of the Earth's orbit is almost a billion kilometers, risky encounters are rare.
Apophis was discovered in July 2004 and approached Earth again in December. The July data was compared with the December data, the orbit was calculated and .. a big commotion began! Calculations have shown that in 2029 Apophis will fall to Earth with a probability of 3%! It was tantamount to a scientifically based prediction of the end of the world. Close observations of Apophis began, each new refinement of the orbit reduced the likelihood of Armageddon. The possibility of a collision in 2029 was practically refuted, but the rapprochement of 2036 fell under suspicion. In 2013, the next flyby of Apophis near the Earth (about 14 million km.) made it possible to refine its size and orbit parameters as much as possible, after which NASA scientists completely refuted the information about the threat of this asteroid falling to Earth.
A little about other small bodies of the solar system.
The most asteroid-dangerous part of our planetary system is left behind, we are moving towards its outskirts. As the distance increases, the potential danger of objects located there decreases accordingly. In other words, if, according to NASA, no one can be afraid of Apophis, then the danger of small bodies, which will be discussed below, completely tends to zero.
Trojans and Greeks.
Each major planet of the solar system has points in its orbit, once in which bodies with a small mass are in equilibrium between this planet and the Sun. These are the so-called Lagrange points, there are 5 of them in total. In two of them, which are 60 ° ahead and behind the planet, "Trojan" asteroids live.
Jupiter has the largest Trojan groups. Those who are ahead of him in orbit are called "Greeks", those who are behind are called "Trojans". About 2000 "Trojans" and 3000 "Greeks" are known. All of them are not located, of course, at one point, but are scattered along the orbit in areas with a length of tens of millions of kilometers.
In addition to Jupiter, Trojan groups have been discovered near Neptune, Uranus, Mars and the Earth. Venus and Mercury most likely also have them, but they have not yet been discovered, since the proximity of the Sun makes it difficult to conduct astronomical observations in these areas. By the way, at the Lagrange points of the Moon relative to the Earth, there are also at least clots of cosmic dust, and possibly small fragments of meteorites that have fallen into a gravitational trap.
Kuiper belt.
Further, as you move away from the Sun, beyond the orbit of Neptune (the most distant planet in the solar system), that is, at a distance of more than 30 AU. from the center, another vast asteroid belt begins - the Kuiper belt. It is approximately 20 times wider than the Main Belt and 100-200 times more massive. Conventionally, its outer boundary is taken to be 55 AU. from the sun. As you can see in the figure, the Kuiper belt is a huge torus (donut) lying beyond the orbit of Neptune: 
More than 1000 Kuiper Belt Objects (KBOs) are already known. Theoretical calculations say that there should be about 500,000 objects larger than 50 km, about 70,000 larger than 100 km, several thousand small planets (and maybe large ones) larger than 1000 km (so far only 7 of them have been discovered).
The most famous Kuiper belt object is Pluto. According to the new definition of the term "planet", it is no longer considered a full-fledged planet, but belongs to the dwarf ones, since it clearly does not dominate in its orbit.
Scattered disk.
The outer boundary of the Kuiper Belt smoothly merges into the Scattered Disk. Here, small bodies rotate in much more elongated and even more inclined orbits. At aphelion, scattered disk objects can move hundreds of AU away.
That is, the objects of this region do not adhere to any strict system in their rotation, but move along a variety of orbits. Therefore, in fact, the disk is called scattered. For example, objects with an orbital inclination of up to 78° have been discovered there. There is also an object that enters the orbit of Saturn and then moves away by 100 AU.
The largest known dwarf planet, Eris, rotates in the scattered disk, its diameter is about 2500 km, which is larger than that of Pluto. At perihelion, it enters the Kuiper belt, and at aphelion it recedes to a distance of 97 AU. from the sun. Its circulation period is 560 years.
The most extreme known object in this region is the dwarf planet Sedna (diameter 1000 km), at its maximum distance, it leaves us at a distance of 900 AU. It takes 11,500 years to revolve around the Sun.
It seems that all this is unattainable distant distances, but!. Two man-made objects are currently located in this area - the Voyager spacecraft, launched back in 1977. Voyager 1 went a little further than its partner, now it is at a distance of 19 billion kilometers from us (126 AU). Both devices are still successfully transmitting information about the level of cosmic radiation to Earth, while the radio signal reaches us in 17 hours. At this rate, the Voyagers will travel 1 light year (a quarter of the distance to the nearest star) in 40,000 years.
And we, mentally, of course, can overcome this distance in an instant. Go ahead..
Oort cloud.
The Oort cloud begins where the scattered disk ends (a distance of 2000 AU is conventionally assumed), that is, it does not have a clear boundary - the scattered disk becomes more and more scattered, and gradually turns into a spherical cloud, consisting of a variety of bodies rotating along a variety of orbits around the sun. At a distance of more than 100,000 AU (approximately 1 light year) The Sun can no longer hold anything with its gravity, so the Oort cloud gradually disappears there and the interstellar void begins.
Here is an illustration from Wikipedia, which clearly shows the comparative size of the Oort Cloud and the inner part of the solar system:
For comparison, the orbit of Sedna (Scattered Disk Object, a dwarf planet with a diameter of about 1000 km) is also shown. Sedna is one of the most distant objects known at the moment, the perihelion of its orbit is 76 AU, the aphelion is 940 AU. Opened in 2003. By the way, it would hardly have been discovered if it were not now in the perihelion region of its orbit, that is, at the closest distance to us, although this is twice as far as to Pluto.
What is a comet.
A comet is an icy small body (water ice, frozen gases, a little meteoric matter), and the Oort Cloud mainly consists of these bodies. Although at such vast distances, modern telescopes cannot see objects about a kilometer in size, it is theoretically predicted that there are several trillion (!!!) of small bodies in the Oort Cloud. All of them are potential nuclei of comets. However, with such grandiose cloud sizes, the average distance between neighboring bodies is measured there in millions, and on the outskirts in tens of millions of kilometers.
Everything that is said about the Oort cloud is openly “on the tip of a pen”, since although we are inside it, it is very far from us. But every year, astronomers discover dozens of new comets approaching the sun. Some of them, the most long-period ones, were thrown into our part of the solar system precisely from the Oort cloud. How could this happen? What exactly brought them here?
The options are:
- There is a large planet(s) in the Oort Cloud that disturbs the orbits of small Oort Cloud Objects.
- Their orbits were scattered when another star passed near the Sun (at an early stage in the evolution of the Solar System, when the Sun was still inside the star cluster that gave birth to it).
- Some long-period comets have been captured by the Sun from a similar "Oort Cloud" of another, smaller star passing nearby.
- All of these options are correct at the same time.
Be that as it may, every year new-discovered comets approach their perihelion, both short-period comets that arrived from the Kuiper belt and the Scattered disk (the period of revolution around the Sun is up to 200 years), and long-period comets from the Oort cloud (they, for revolution around the Sun tens of thousands of years are required). Basically, they do not fly too close to the Earth, so only astronomers see them in. But sometimes such guests put on a beautiful space show: 
What if..
What will happen if, after all, a comet or an asteroid falls to Earth, because this has happened many times in the past? About this in
To date, about 1,500 potentially dangerous astronomical objects have been discovered. NASA refers to all asteroids and comets that are more than 100-150 meters in diameter and can approach the Earth closer than 7.5 million kilometers. Four of them have been assigned a fairly high level of danger according to the Palermo scale.
According to the Palermo scale, astronomers calculate how dangerous this or that asteroid is approaching our planet. The indicator is calculated according to a special formula: if the result is -2 or less, then the probability of a body collision with the Earth is practically absent, from -2 to 0 - the situation requires careful observation, from 0 and above - the object is most likely to collide with the planet. There is also the Turin scale, but it is subjective.
During the entire existence of the Palermo scale, only two objects received a value above zero: 89959 2002 NT7 (0.06 points) and 99942 Apophis (1.11 points). After their discovery, astronomers began to closely study the orbits of asteroids. As a result, the probability of a collision of both bodies with the Earth was completely excluded. Additional research almost always results in a lower hazard rating, as it allows you to study the trajectory of the object in more detail.
Now only four asteroids have a danger rating above -2: 2010 GZ60 (-0.81), 29075 1950 DA (-1.42), 101955 Bennu 1999 RQ36 (-1.71) and 410777 2009 FD (-1.78 ). Of course, there are still plenty of objects less than 100 meters in diameter, which in theory can collide with the Earth, but NASA watches them less closely - this is an expensive and technically difficult task.
Asteroid 2010 GZ60 (diameter - 2000 meters) in the period from 2017 to 2116 will approach the Earth 480 times. Some approaches will be quite close - just a few radii of our planet. 29075 1950 DA is slightly smaller (about 1300 meters), but a collision with it will cause catastrophic consequences for humanity - there will be global changes in the biosphere and climate. True, this can happen only in 2880, and even then the probability is very low - approximately 0.33 percent.
101955 Bennu 1999 RQ36 is 490 meters in diameter and will share Earth 78 times from 2175 to 2199. In the event of a collision with the planet, the force of the explosion will be 1150 megatons of TNT. For comparison: the force of the most powerful explosive device AN602 was 58 megatons. 410777 2009 FD is considered potentially dangerous until 2198, it will fly closest to Earth in 2185. The diameter of the asteroid is 160 meters.
No matter how skeptical people are about the Hollywood story about the fall of a giant asteroid to Earth, space can still pose a serious danger to our planet. The most real threat, by and large, comes from the depths of the vast universe.
Scientists have found that in the history of the planet there have been numerous collisions with asteroids, and with rather serious consequences. This explains the attention of scientists to dangerous asteroids. These asteroids include those whose hypothetical collision with our planet could lead to the death of mankind. Thus, NASA scientists have identified over 150 celestial bodies that pose a potential threat to human civilization.
The topic of “asteroid attacks” has recently become a topic of interest for scientists. Thus, the fall of meteorites until the second half of the 18th century was taken as an optical illusion. Experts back in the 1960s tried to explain the appearance of craters by "terrestrial" reasons. Now their cosmic origin is beyond doubt.
So, the death of dinosaurs is recorded on the "conscience" of the asteroid, the diameter of which was about 15 kilometers. 65 million years ago, a collision with this asteroid, along with dinosaurs, sent about 85% of plant and animal species to the next world. As a result of the fall of this giant asteroid, a crater was formed, the diameter of which was 200 kilometers. Billions of tons of water vapor and dust, as well as ash and soot from the monstrous fire, rose into the atmosphere. All this eclipsed the sunlight for many months. This could lead to a catastrophic drop in temperature on Earth.
There are many predictions and facts that point to the end of the world in 2012. But how exactly this will happen, no one knows. The Earth is just a crumb in the Universe, which appeared as a result of the interaction of cosmic bodies, and it is possible that it will also disappear. The fall of the asteroid, most likely, will not destroy the planet itself, but will rid it of people, animals and plants, i.e. from life. Will the Earth shatter into many pieces? Or maybe turn into Mars? So far, one can only speculate on this subject, based on the data that NASA shares with the general public.
Asteroids and comets often fly in quite dangerous proximity to the Earth, and even the slightest violation of their trajectory can lead to unpredictable consequences. So, if a comet falls on glaciers, it will cause them to melt, global warming, and floods. Some scientists claim that in the entire history of the planet Earth, it collided with an asteroid about 6 times. Craters testify to this, the origin of which can only be explained by the fall of an asteroid to Earth.
The consequences of the fall of an asteroid can be very different. It all depends on the size of the asteroid, the place where it will fall, and on the speed of its movement. So, for example, an asteroid with a diameter of about 500 km will lead to the death of all life on Earth, and within a day. The impact force will cause a firestorm that will sweep away all life in its path. In less than a day, a wave of death will circle the planet and destroy all life on it. It is likely that the simplest organisms will survive and start anew the process of evolution on Earth.
An asteroid with a smaller diameter, when falling into the ocean, can cause a giant tsunami up to 100 meters high. Such a wave can wash away kilometers of the coastal zone from the face of the planet. Such a tsunami, among other things, can cause a number of man-made disasters. If the asteroid falls on any continent, then it will immediately destroy a giant part of the land. All life on the planet will perish as a result.
Should we expect such an end of the world? Amy Mainzer, one of the employees of the NASA Jet Propulsion Laboratory, claims that hundreds of asteroids are currently orbiting the Earth, capable of destroying all life on the planet. The chances of a planet colliding with an asteroid, according to calculations, are now small. However, one cannot be completely sure of this, since the cosmos is completely unpredictable. Perhaps a dangerous asteroid is flying towards the Earth at this very moment. Technologies are now developing quite rapidly, however, despite this, there is still no system that could give accurate information regarding the movement of all space bodies. But to imagine the full power of the potential danger, it is enough to look at the location of the asteroid belt relative to our planet.
Mars is closest to the belt. At the moment, there is a lot of evidence that there was once life on this planet, but for unknown reasons, it died. The most likely version of death is the fall of an asteroid. The powerful wave formed during the impact destroyed all life. The next victim may well be the Earth, as it is quite close to the asteroid belt.
Scientists such as Morrison and Chapman argue that once every 500 thousand years a global catastrophe occurs on the planet due to the fall of asteroids. According to statistics, asteroids as small as 10 kilometers fall every 100 million years. They leave almost no chance for humanity and the animal world to survive. Scientists believe that if such a collision occurs in our time, all of humanity will perish. According to experts, the biggest threat comes from medium-sized celestial bodies. According to experts, over 500 thousand years, more than a billion people died as a result of the falls of such bodies. The earth was constantly bombarded by space.
Currently, according to scientists, the most dangerous for our planet are such asteroids as the asteroid YU 55, Eros, Vesta and Apophis. The fact that there is a real threat from outer space was only discussed when the asteroid Apophis was discovered. Its diameter is approximately 270 meters, and its weight is about 27 million tons. The collision of this asteroid with the Earth, according to the latest data, is possible in 2036. Even if it does not fall to Earth, it can cause significant damage to space technology. It will approach the Earth at a distance of 30-35 thousand kilometers, and it is at this altitude that most of the spacecraft operate. Apophis is currently considered the first among potentially dangerous celestial bodies. In 2013, it will fly relatively close to our planet and scientists will be able to see the true nature of the threat and determine whether it is possible to somehow prevent a catastrophe.
Russian scientists did not wait for 2013 and created a group to decide what to do if it turns out that the collision of Apophis with the Earth does happen. The approach of the asteroid in 2029 to the Earth will change its orbit, for this reason, predictions about the subsequent direction of movement are very uncertain without more data. After hitting the Earth's surface an asteroid, according to preliminary estimates, there will be a powerful explosion of 200 megatons.
Also, the asteroid 2005 YU 55 is constantly approaching the Earth with a certain frequency. In November 2011, it flew past our planet at a dangerously close distance. And since then, it has been considered one of the most dangerous asteroids. The largest asteroid in the belt is Vesta, which is visible to the naked eye from Earth. This is explained by its ability to approach the planet at a distance of only 170 million kilometers. And there are a lot of such potentially dangerous asteroids.
But, despite this, astronomers currently do not see any serious danger for the Earth from asteroids. But, as mentioned earlier, space is unpredictable, so potentially dangerous objects are constantly monitored. For these purposes, especially powerful space telescopes with especially sensitive optics are being developed. Without them, it is quite difficult to spot asteroids, as they reflect light rather than emit it.
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Planet Earth is constantly exposed to dangers because there are asteroid belts nearby. According to scientists, there are about 17 thousand dangerous objects near the planet, their fall to Earth can cause serious problems for the population of the planet.
Our planet has a powerful gravitational field, and the fall of a meteorite on it is reduced to zero, but scientists never exclude this possibility. Scientists have discovered that asteroids may still fall on Earth next year.
The researchers analyzed the information and compiled a list of meteorites that may threaten our planet. According to experts, in the new year 90 celestial bodies will fly past the Earth and 13 of them have become a threat to the Earth.
The first will approach the Earth in the month of January, these are "306383 1993 VD" and "2003 CA4". Also, quite large asteroids are expected in February, these are the 400-meter "2015 BN509" and the 100-meter "2014 WQ202" and most of the celestial bodies will fly by our planet in May and November.
But the biggest danger is the asteroid, "2015 DP155" which will fly by early in the morning on June 11, 2018. It always moves in the outer orbit of Mars, but once every two hundred years it moves closer to the sun. Therefore, it will not be difficult for him to approach the Earth. It still has not small dimensions of about 280 meters, in order to completely burn out in the earth's atmosphere.
According to researchers, there are a lot of large asteroids in the solar system, and all of them pose a danger to our planet. According to experts, for the population of the Earth, collisions of large celestial bodies with each other are also dangerous. The particles will enter the atmosphere and leave ozone holes, they say, leading to high levels of direct sunlight hitting the surface.
Scientists say that the collision of the Earth and an asteroid is very rare. Huge cataclysms on our planet have happened several times in the history of mankind. One of the most powerful cataclysms is the fall of a meteorite, which destroyed the dinosaurs and some other representatives of the terrestrial fauna. There was also a case of a meteorite falling in ancient Egypt, but it is mentioned only in the annals.
The probabilities of a person's death from a collision of the Earth with an asteroid or other celestial body can be compared with death in a car accident. And yet it will depend on the size of the celestial body. That is, if we are talking about a sufficiently large object, then it will only affect one continent.
And this means that there can be no talk of any apocalypse. A great danger to the population of the Earth is provided by the fall of a meteorite into the ocean. In this case, this cataclysm can cause a tsunami, and this, in turn, will bring huge destruction. According to experts, the probability of asteroids and comets colliding with oceans and seas is much higher than with the earth's surface.
Asteroids that threaten the Earth
Are they really that dangerous?
In recent years, reports of new dangerous asteroids now and then appear in the news bulletins. Perhaps the most famous of them, the asteroid Apophis, has a rather sinister name.
Previously, there was no such thing. And now reports of new asteroids threatening the Earth are pouring in every few months. True, then messages about updated calculations follow and the next doomsday is canceled.
The layman gets the feeling that someone is almost "shooting" at our planet. And, if we still remember the horrors from the fall of the Tunguska, and more recently the Chelyabinsk meteorites, then it really is time to ring all the bells.
If we look in astronomical reference books, we will see that almost every year quite large asteroids threatening the earth, several hundred meters in size. If such a block falls on the Earth, the gravest consequences cannot be avoided. The fall of an asteroid larger than a kilometer can lead to the death of an entire continent and a long "nuclear winter". If such a mountain falls into the ocean, then a tsunami will cover all the continents. And these are only those asteroids that have been discovered in recent years, and how many more are undiscovered?!
Dinosaurs are supposed to have died out from the fall of a giant meteorite in the Yucatan... (although debatable, but not without reason).
At one time, the asteroid 2004 VD17 was considered the most dangerous asteroid threatening the Earth. Its diameter is 580 meters. The probability of its collision with the Earth in 2102 was 1/1000 - this is five times higher than the probability of the Earth colliding with the famous asteroid Apophis in 2036 ... Upon impact, a crater with a diameter of 10 km would have formed, the magnitude of the earthquake was 7.4 points.
But, after all, asteroids threatening the Earth did not appear yesterday, they have existed since the birth of the solar system. How many of them really fell in the memory of mankind? In memory - only the Tunguska meteorite. Of course, the Chelyabinsk meteorite brought a lot of trouble, but it was a relatively small "pebble".
Then where does such a flurry of reports about probable collisions of asteroids with the Earth come from? Everything is simple...
In the recent year 1976, the asteroid 2010 XC15 flew within half the distance from the Earth to the Moon. If it happened now, how much noise would be raised ... But then no one knew about it, it was only realized many years later as a result of calculations. It's just that at that time there were not enough tools to detect this asteroid dangerous for the Earth. And how many more such asteroids that threaten the Earth flew by...
In recent years, everything has changed. More advanced telescopes appeared, and their number increased dramatically. Powerful computers appeared, and mathematical methods for calculating the trajectories of the movement of space bodies.
Finally, telescopes became available to amateur astronomers, which they could not have dreamed of only 25 years ago. The dream of Soviet amateur astronomers was the "Small school refractor telescope" with an aperture of only 60 mm. The ultimate dream for most was the "Large school refractor telescope" with an aperture of as much as 80 mm.! It was difficult to get them - they were sold only in educational collectors, at the request of schools and were stored there. (amateurs managed to build somewhat large telescopes, but these were isolated cases)
Now such telescopes are entry-level and are available in any store, costing only a few thousand rubles. Now a telescope with an aperture of 200 mm. - not such a rarity for an amateur astronomer. The most advanced build devices with an aperture of 300 mm or more.
Automated guidance and tracking systems for telescopes. Computer image processing, often semi-automated. This is also not uncommon. It all costs, of course, more than a "pack of cigarettes", but these are not exorbitant figures, especially for those who are really looking for new asteroids that threaten the Earth. Logic dictates that it will be even cooler.
Finally, the Internet appeared, with the help of which you can not only get any information, but also quickly contact other observatories to clarify the parameters of the movement of new objects. Previously, only letters, telegrams, and a telephone that was not everywhere, the "intercity" worked poorly, and you can't dictate too much data on it.
Here it is necessary to make a reservation that many designs of commercial telescopes are not very suitable for searching for new asteroids. Therefore, inveterate hunters for new asteroids often make them according to their drawings. Nevertheless, shop telescopes are quite suitable, there would be desire, perseverance, time and "flair" ...
Of course, not only amateurs are engaged in the search for asteroids that threaten the Earth. Orbital telescopes are also constantly surveying the surrounding space.
As a result, the Earth seemed to take off the blindfold and began to see clearly. Dozens of heavily armed astronomers scour the sky every night, competing with themselves and orbiting telescopes to see who can spot a new object faster. And it happens that asteroids threatening the earth Opened by amateurs, not professionals! There are just more of us ;-)
Hence the increase in reports of new dangers from outer space.
Here too - the love of the media for everything new and loud. A rare editorial staff will refuse to talk about another asteroid that threatens the Earth - the main thing for them is that the news contains at least a hint of danger ...
By the way, do not forget about the financial interest of NASA and other space agencies ... The more this noise, the easier it is to knock out finances for "anti-meteorite protection of the Earth" ;-)
At the same time, of course, no one canceled the danger itself. Asteroids that threaten the Earth have been and will be, we are just lucky so far that none of the discovered asteroids yet belongs to unconditionally dangerous ones. Moreover, the earth civilization is not yet so developed as to easily prevent a collision, we are only on the threshold of this.
Therefore, stirring up the minds is not only useful, but also necessary. Means to prevent the threat of Earth impact with asteroids should be prepared now, so that at least part of the work will be done by the time it is really needed.
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