Research project on the topic: "Asteroid danger." Presentation on the topic: Asteroid safety of the earth This is how a blast wave from a falling meteorite can be formed

Today we will learn: 1. What is an asteroid. 2. What collisions of the Earth with smaller celestial objects have occurred. 3. What are Star Wounds? 4. Why do global catastrophes occur every 30 million years? 5. What asteroids are known in Russia. 6. What is the Tunguska phenomenon. 7. What kind of meteorites were there in the 20th century? 8. What can happen due to a collision with a comet. 9. What are asteroids like today? 10. What kind of protection does the Earth have from bombing from space? Tracking celestial bodies. Protection Options.

What is an asteroid? An asteroid is a relatively small celestial body in 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. The term asteroid (from ancient Greek στεροειδής “like a star”, from στήρ “star” and ε ̓ δος “appearance, appearance, quality”) was introduced by William Herschel on the basis that these objects looked like points when observed through a telescope stars, unlike planets, which look like disks when viewed through a telescope. The exact definition of the term "asteroid" is still not established. Until 2006, asteroids were also called minor planets. The main parameter by which classification is carried out is body size. Asteroids are considered bodies with a diameter of more than 30 m

Collisions of the Earth with smaller celestial objects. The Earth has many opportunities to encounter small celestial objects. Among the asteroids, the orbits of which, as a result of the long-term action of giant planets, can cross the orbit of the Earth, there are at least 200 thousand objects with diameters of about 100 m. Our planet collides with such bodies at least once every 5 thousand years. Therefore, approximately 20 craters with a diameter of more than 1 km are formed on Earth every 100 thousand years. Small asteroid fragments (meter-sized blocks, stones and dust particles, including those of cometary origin) continuously fall to the Earth.

“Star wounds” When a large celestial body falls onto the surface of the Earth, craters are formed. Such events are called astra problems, “star wounds”. On Earth they are not very numerous (compared to the Moon) and are quickly smoothed out under the influence of erosion and other processes. A total of 120 craters have been found on the surface of the planet. 33 craters have a diameter of more than 5 km and are about 150 million years old. The first crater was discovered in the 1920s in Devil's Canyon in the North American state of Arizona. Fig. 15 The diameter of the crater is 1.2 km, the depth is m, the approximate age is 49 thousand years. According to scientists' calculations, such a crater could have formed when the Earth collided with a body of forty meters in diameter.

Global catastrophes every 30 million years. According to modern science, in just the last 250 million years there have been nine extinctions of living organisms with an average interval of 30 million years. These disasters can be associated with the fall of large asteroids or comets to Earth. Let us note that it is not only the Earth that suffers from uninvited guests. Spacecraft photographed the surfaces of the Moon, Mars, and Mercury. The craters are clearly visible on them, and they are much better preserved due to the peculiarities of the local climate.

Asteroids in Russia. On the territory of Russia, several “star wounds” stand out: in the north of Siberia - 1. Popigaiskaya - with a crater diameter of 100 km and an age of millions of years, 2. Puchezh-Katunskaya - with a crater of 80 km, the age of which is estimated at 180 million years, 3. Kara - with a diameter of 65 km and age - 70 million years.

Tunguska phenomenon A Tunguska object that caused an explosion with a power of 20 megatons at an altitude of 5-8 km above the Earth's surface. To determine the power of the explosion, it is equated in its destructive effect on the environment to the explosion of a hydrogen bomb with a TNT equivalent, in this case 20 megatons of TNT, which is 100 times greater than the energy of the nuclear explosion in Hiroshima. According to modern estimates, the mass of this body could reach from 1 to 5 million tons. An unknown body invaded the earth's atmosphere on June 30, 1908 in the Podkamennaya Tunguska River basin in Siberia. Since 1927, eight expeditions of Russian scientists successively worked at the site of the fall of the Tunguska phenomenon. It was determined that within a radius of 30 km from the explosion site, all the trees were knocked down by the shock wave. The radiation burn caused a huge forest fire. The explosion was accompanied by a strong sound. Over a vast territory, according to the testimony of residents of the surrounding (very rare in the taiga) villages, unusually light nights were observed. But none of the expeditions found a single piece of the meteorite. Many people are more accustomed to hearing the phrase “Tunguska meteorite,” but until the nature of this phenomenon is reliably known, scientists prefer to use the term “Tunguska phenomenon.”

Collision with a comet. All of the above concerns collisions of the Earth with a specific solid body. But what can happen in a collision with a comet of huge radius filled with meteorites? The fate of the planet Jupiter helps answer this question. In July 1996, Comet Shoemaker-Levy collided with Jupiter. Two years earlier, during the passage of this comet at a distance of 15 thousand kilometers from Jupiter, its core split into 17 fragments of approximately 0.5 km in diameter, stretching along the comet’s orbit. In 1996, they one by one penetrated into the thickness of the planet. The collision energy of each piece, according to scientists, reached approximately 100 million megatons. In photographs from the space telescope. Hubble (USA) shows that as a result of the catastrophe, giant dark spots formed on the surface of Jupiter - emissions of gas and dust into the atmosphere in places where fragments burned. The spots corresponded to the size of our Earth!

Asteroids today. In recent years, reports about asteroids approaching the Earth have increasingly appeared on radio, television and in newspapers. This does not mean that there are significantly more of them than before. Modern observational technology allows us to see kilometer-long objects at a considerable distance. In March 2001, the asteroid "1950 DA", discovered back in 1950, flew at a distance of 7.8 million kilometers from Earth. Its diameter was measured to be 1.2 kilometers. Having calculated the parameters of its orbit, 14 reputable American astronomers published the data in the press. In their opinion, on Saturday March 16, 2880, this asteroid may collide with the Earth. There will be an explosion with a power of 10 thousand megatons. The probability of a disaster is estimated at 0.33%. But scientists are well aware that it is extremely difficult to accurately calculate the orbit of an asteroid due to unforeseen influences on it from other celestial bodies.

Asteroids today Currently, about 10 asteroids are known to be approaching our planet. Their diameter is more than 5 km. According to scientists, such celestial bodies can collide with the Earth no more than once every 20 million years. For the largest representative of the population of asteroids approaching the Earth's orbit, the 40-kilometer Ganymede, the probability of colliding with the Earth in the next 20 million years does not exceed 0.00005 percent. The probability of a collision with the Earth by the 20-kilometer asteroid Eros is estimated for the same period at approximately 2.5%.

Asteroids today Scientists have calculated that the impact energy corresponding to a collision with an asteroid with a diameter of 8 km should lead to a catastrophe on a global scale with shifts in the earth's crust. In this case, the size of the crater formed on the Earth's surface will be approximately 100 km, and the depth of the crater will be only half the thickness of the earth's crust. If the cosmic body is not an asteroid or meteorite, but is the nucleus of a comet, then the consequences of a collision with the Earth can be even more catastrophic for the biosphere due to the strong dispersion of cometary matter.

Tracking celestial bodies To protect the Earth from meeting space guests, a constant monitoring (tracking) service was organized for all objects in the sky. At large observatories, robotic telescopes monitor the sky. Most of the world's observatories participate in this program and make their contribution. The introduction of the Internet into people's lives has allowed all amateur astronomers to connect to this good cause. A web-based asteroid hazard monitoring network has been created. NASA announced the creation of a worldwide asteroid hazard monitoring system, called Sentry. The system was created to facilitate communication between scientists when discovering celestial bodies that pose a potential threat to our planet. Space aliens over several meters in size approaching the Earth can be detected by modern optical means at a distance of about 1 million km from the planet. Larger objects (tens and hundreds of meters in diameter) can be seen at much greater distances.

Defense Options So, the object has been detected, and it is indeed approaching the Earth. Science fiction writers and astronomers agree that there are only two possible defense options. The first is to destroy the object physically - blow it up, shoot it. The second is to change its orbit to prevent a collision. Recently, however, a message appeared that they had come up with a kind of airbag that should be deployed at the place where the cosmic body falls. Or science fiction writers are actively developing versions of the evacuation of earthlings to another planet in the solar or even another planetary system.

The implementation of the first of these methods is obvious. You need to use a rocket to deliver an explosive there and detonate it. It is possible to organize a contact nuclear explosion on the surface. All this should lead to the fragmentation of the object into harmless fragments. The only question is the amount of explosive and its delivery to the trajectory point of an asteroid or comet, sufficiently distant from the Earth. The method of detonating a cosmic body is applicable only for small objects, since as a result scientists expect to obtain small fragments that burn up in the atmosphere.

It's more difficult with larger bodies. Due to the limited capabilities of modern demolition means, after an explosion large fragments may remain unburned in the atmosphere, the collective action of which can cause a catastrophe much greater than the original body. And since it is almost impossible to calculate the number of fragments, their speed and direction of movement, then the crushing of the body itself becomes a dubious enterprise.

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“Star wounds” When a large celestial body falls onto the surface of the Earth, craters are formed. Such events are called astroproblems, “star wounds”. On Earth they are not very numerous (compared to the Moon) and are quickly smoothed out under the influence of erosion and other processes. A total of 120 craters have been found on the surface of the planet. 33 craters have a diameter of more than 5 km and are about 150 million years old. The first crater was discovered in the 1920s in Devil's Canyon in the North American state of Arizona. Fig. 15 The diameter of the crater is 1.2 km, depth is 175 m, approximate age is 49 thousand years. According to scientists' calculations, such a crater could have been formed when the Earth collided with a body of forty meters in diameter.

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More interesting are the ways to change the orbit of a cosmic body. These methods are good for large bodies. If we have a comet approaching the Earth, then it is proposed to use the sublimation effect - the evaporation of gases from the surface of the cleaned part of the comet's nucleus. This process leads to the emergence of reactive forces that spin the comet around its own axis of rotation and change the trajectory of its movement. This is very reminiscent of “spin” goals in football or tennis, when the ball flies along a completely different trajectory, unexpected for the goalkeeper. The question arises: how to clean the kernel? There are many ways to do this. They even came up with a “sandblasting machine” for cleaning. It is proposed to detonate a rocket or a small nuclear charge near the comet's nucleus and fragments of the rocket or the blast wave of the projectile will clear part of the comet's nucleus. More interesting are the ways to change the orbit of a cosmic body. These methods are good for large bodies. If we have a comet approaching the Earth, then it is proposed to use the sublimation effect - the evaporation of gases from the surface of the cleaned part of the comet's nucleus. This process leads to the emergence of reactive forces that spin the comet around its own axis of rotation and change the trajectory of its movement. This is very reminiscent of “spin” goals in football or tennis, when the ball flies along a completely different trajectory, unexpected for the goalkeeper. The question arises: how to clean the kernel? There are many ways to do this. They even came up with a “sandblasting machine” for cleaning. It is proposed to detonate a rocket or a small nuclear charge near the comet's nucleus and fragments of the rocket or the blast wave of the projectile will clear part of the comet's nucleus.

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The same can be done with an asteroid. But in this case, it is proposed to first cover part of its surface with chalk. It will begin to reflect the sun's rays better. There will be uneven heating of its “body” - the speed and direction of its rotation around its axis will change. Then everything will happen as with a “twisted” ball. Only you will need a lot of chalk. American scientists have calculated that changing the orbit of the 1950 DA asteroid would require 250 thousand tons of chalk, and 90 fully loaded Saturn 5-type comets could deliver it to the asteroid. But at the same time, in one century its orbit would deviate by 15 thousand kilometers. The same can be done with an asteroid. But in this case, it is proposed to first cover part of its surface with chalk. It will begin to reflect the sun's rays better. There will be uneven heating of its “body” - the speed and direction of its rotation around its axis will change. Then everything will happen as with a “twisted” ball. Only you will need a lot of chalk. American scientists have calculated that changing the orbit of the 1950 DA asteroid would require 250 thousand tons of chalk, and 90 fully loaded Saturn 5-type comets could deliver it to the asteroid. But at the same time, in one century its orbit would deviate by 15 thousand kilometers. There has been serious discussion of a way to launch a large solar array into orbit around an asteroid so that the asteroid encounters it and it becomes stuck on its surface, reflecting the sun's rays. Science fiction writers write a lot about spaceships capable of transporting an asteroid away from Earth. But so far none of the invented methods have been applied in practice.

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Boris Zakirov, 7th grade student, Municipal Educational Institution Secondary School No. 7, Lyubertsy

The problem of asteroid danger is international in nature. The most active countries in solving this problem are the USA, Italy and Russia. A positive fact is that cooperation on this issue is being established between nuclear specialists and the military of the United States and Russia. The military departments of the largest countries are indeed able to unite their efforts against the “common enemy” of humanity - the asteroid danger and, as part of the conversion, begin to create a global system for protecting the Earth. This cooperative cooperation would contribute to the growth of trust and detente in international relations, the development of new technologies, and the further technical progress of society.

It is noteworthy that the awareness of the reality of the threat of cosmic collisions coincided with a time when the level of development of science and technology already makes it possible to put on the agenda and solve the problem of protecting the Earth from asteroid danger. This means that there is no hopelessness for earthly civilization in the face of a threat from outer space or, in other words, we have a chance to protect ourselves from collisions with dangerous space objects. Whether we can use it depends not only on scientists, but also on politicians. It is absolutely obvious that without the development of science and the acquisition of new scientific knowledge, it is impossible to solve the global problems of human survival. And one of the most “fundamental” sciences, astronomy, makes it possible to preserve civilization in the solar system and provide its existence with raw materials. Scientists-astronomers understand this and are ready to fulfill the mission entrusted to them. However, for this it is necessary to understand their responsibility for the fate of Humanity and the policies on which the state of science in society depends.

The asteroid danger is among the most important global problems that humanity will inevitably have to solve through the united efforts of various countries.

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Every day, rocks fall to Earth from space. Large stones naturally fall less often than small ones. The smallest specks of dust penetrate tens of kilograms into the Earth every day. Larger pebbles fly through the atmosphere like bright meteors. Rocks and pieces of ice the size of a baseball or smaller, flying through the atmosphere, evaporate completely. As for large rock fragments, up to 100 m in diameter, they pose a significant threat to us, colliding with the Earth approximately once every 1000 years. If dropped into the ocean, an object of this size could cause a tidal wave that would be destructive over long distances. A collision with a massive asteroid more than 1 km across is a much rarer event, occurring once every few million years, but its consequences can be truly catastrophic. Many asteroids go undetected until they get close to Earth. One of these asteroids was discovered in 1998 while studying an image taken by the Hubble Space Telescope (blue dash in the image). Last week, the small 100-meter asteroid 2002 MN was discovered after it passed the Earth, passing inside the orbit of the Moon. The passage of asteroid 2002 MN near Earth is the closest we have seen in the last eight years since the passage of asteroid 1994 XM1. A collision with a large asteroid would not change the Earth's orbit very much. In this case, however, such an amount of dust would arise that the earth's climate would change. This would entail the widespread extinction of so many forms of life that the extinction of species occurring today would seem insignificant.

Currently, about 10 asteroids are known to be approaching our planet. Their diameter is more than 5 km. According to scientists, such celestial bodies can collide with the Earth no more than once every 20 million years.

For the largest representative of the population of asteroids approaching the Earth's orbit, the 40-kilometer Ganymede, the probability of colliding with the Earth in the next 20 million years does not exceed 0.00005 percent. The probability of a collision with the Earth by the 20-kilometer asteroid Eros over the same period is estimated at approximately 2.5%.

The number of asteroids with a diameter of more than 1 km crossing the Earth’s orbit is approaching 500. A fall of such an asteroid onto the Earth can occur on average no more than once every 100 thousand years. The fall of a body 1-2 km in size can already lead to a planetary catastrophe.

In addition, according to available data, the Earth’s orbit is crossed by about 40 active and 800 extinct “small” comets with a nucleus diameter of up to 1 km and 140-270 comets reminiscent of Halley’s comet. These large comets left their imprints on the Earth - 20% of the Earth's large craters owe their existence to them. In general, more than half of all craters on Earth are of cometary origin. And now 20 minicomet cores, each weighing 100 tons, fly into our atmosphere every minute.

Scientists have calculated that the impact energy corresponding to a collision with an asteroid with a diameter of 8 km should lead to a catastrophe on a global scale with shifts in the earth's crust. In this case, the size of the crater formed on the Earth's surface will be approximately 100 km, and the depth of the crater will be only half the thickness of the earth's crust.

If the cosmic body is not an asteroid or meterite, but is the nucleus of a comet, then the consequences of a collision with the Earth can be even more catastrophic for the biosphere due to the strong dispersion of cometary matter.

The Earth has significantly more opportunities to encounter small celestial objects. Among the asteroids, the orbits of which, as a result of the long-term action of giant planets, can cross the orbit of the Earth, there are at least 200 thousand objects with diameters of about 100 m. Our planet collides with such bodies at least once every 5 thousand years. Therefore, approximately 20 craters with a diameter of more than 1 km are formed on Earth every 100 thousand years. Small asteroid fragments (meter-sized blocks, stones and dust particles, including those from comets) continuously fall to the Earth.

When a large celestial body falls onto the Earth's surface, craters are formed. Such events are called astroproblems, “star wounds”. On Earth they are not very numerous (compared to the Moon) and are quickly smoothed out under the influence of erosion and other processes. A total of 120 craters have been found on the surface of the planet. 33 craters have a diameter of more than 5 km and are about 150 million years old.

The first crater was discovered in the 1920s in Devil's Canyon in the North American state of Arizona. Fig. 15 The diameter of the crater is 1.2 km, depth is 175 m, approximate age is 49 thousand years. According to scientists' calculations, such a crater could have been formed when the Earth collided with a body of forty meters in diameter.

Geochemical and paleontological data indicate that approximately 65 million years ago, at the turn of the Mesozoic period of the Cretaceous era and the Tertiary period of the Cenozoic era, a celestial body approximately 170-300 km in size collided with the Earth in the northern part of the Yucatan Peninsula (the coast of Mexico). The trace of this collision is a crater called Chicxulub. The power of the explosion is estimated at 100 million megatons! This created a crater with a diameter of 180 km. The crater was formed by the fall of a body with a diameter of 10-15 km. At the same time, a gigantic cloud of dust weighing a total of one million tons was thrown into the atmosphere. The six-month night has arrived on Earth. More than half of the existing plant and animal species died. Perhaps then, as a result of global cooling, dinosaurs became extinct.

According to modern science, in just the last 250 million years there have been nine extinctions of living organisms with an average interval of 30 million years. These disasters can be associated with the fall of large asteroids or comets to Earth. Let us note that it is not only the Earth that suffers from uninvited guests. Spacecraft photographed the surfaces of the Moon, Mars, and Mercury. The craters are clearly visible on them, and they are much better preserved due to the peculiarities of the local climate.

On the territory of Russia, several astroproblems stand out: in the north of Siberia - Popigaiskaya - with a crater diameter of 100 km and an age of 36-37 million years, Puchezh-Katunskaya - with a crater of 80 km, whose age is estimated at 180 million years, and Karskaya - with a diameter of 65 km and age - 70 million years.

Tunguska phenomenon

In the 20th century, 2 large celestial bodies fell to Russian Earth. Firstly, the Tunguz object, which caused an explosion with a power of 20 megatons at an altitude of 5-8 km above the Earth's surface. To determine the power of the explosion, it is equated in its destructive effect on the environment to the explosion of a hydrogen bomb with a TNT equivalent, in this case 20 megatons of TNT, which is 100 times greater than the energy of the nuclear explosion in Hiroshima. According to modern estimates, the mass of this body could reach from 1 to 5 million tons. An unknown body invaded the earth's atmosphere on June 30, 1908 in the Podkamennaya Tunguska River basin in Siberia.

Since 1927, eight expeditions of Russian scientists successively worked at the site of the fall of the Tunguska phenomenon. It was determined that within a radius of 30 km from the explosion site, all the trees were knocked down by the shock wave. The radiation burn caused a huge forest fire. The explosion was accompanied by a strong sound. Over a vast territory, according to the testimony of residents of the surrounding (very rare in the taiga) villages, unusually bright nights were observed. But none of the expeditions found a single piece of the meteorite.

Many people are more accustomed to hearing the phrase “Tunguska meteorite,” but until the nature of this phenomenon is reliably known, scientists prefer to use the term “Tunguska phenomenon.” Opinions about the nature of the Tunguz phenomenon are the most controversial. Some consider it to be a stone asteroid with a diameter of approximately 60-70 meters, which collapsed when falling into pieces of approximately 10 meters in diameter, which then evaporated in the atmosphere. Others, and most of them, say that this is a fragment of Comet Encke. Many associate this meteorite with the Beta Taurid meteor shower, the ancestor of which is also Comet Encke. Proof of this can be the fall of two other large meteors to Earth in the same month of the year - June, which were not previously considered on a par with Tunguska. We are talking about the Krasnoturansky bolide of 1978 and the Chinese meteorite of 1876.

Many scientific and science fiction books have been written on the topic of the Tunguz meteorite. What kind of objects were not attributed to the role of the Tunguz phenomenon: flying saucers and ball lightning and even the famous Halley's comet - as far as the imagination of the authors was enough! But there is no final opinion about the nature of this phenomenon. This mystery of nature has not yet been solved.

A realistic estimate of the energy of the Tunguska phenomenon is approximately 6 megatons. The energy of the Tunguska phenomenon is equivalent to an earthquake with a magnitude of 7.7 (the energy of the strongest earthquake is 12).

The second large object found on Russian territory was the Sikhote-Alin iron meteorite, which fell in the Ussuri taiga on February 12, 1947. It was significantly smaller than its predecessor, and its mass was tens of tons. It also exploded in the air before reaching the surface of the planet. However, over an area of 2 square kilometers, more than 100 craters with a diameter of just over a meter were discovered. The largest crater found was 26.5 meters in diameter and 6 meters deep. Over the past fifty years, over 300 large fragments have been found. The largest fragment weighs 1,745 kg, and the total weight of the collected fragments exceeded 30 tons of meteoric material. Not all the fragments were found. The energy of the Sikhote-Alinin meteorite is estimated at about 20 kilotons.

Russia was lucky: both meteorites fell in a deserted area. If the Tunguska meteorite fell on a large city, then there would be nothing left of the city and its inhabitants.

Of the large meteorites of the 20th century, the Brazilian Tunguzka deserves attention. He fell on the morning of September 3, 1930 in a deserted area of the Amazon. The power of the explosion of the Brazilian meteorite corresponded to one megaton.

All of the above concerns collisions of the Earth with a specific solid body. But what can happen in a collision with a comet of huge radius filled with meteorites? The fate of the planet Jupiter helps answer this question. In July 1996, Comet Shoemaker-Levy collided with Jupiter. Two years earlier, during the passage of this comet at a distance of 15 thousand kilometers from Jupiter, its core split into 17 fragments of approximately 0.5 km in diameter, stretching along the comet’s orbit. In 1996, they one by one penetrated into the thickness of the planet. The collision energy of each piece, according to scientists, reached approximately 100 million megatons. In photographs from the space telescope. Hubble (USA) shows that as a result of the catastrophe, giant dark spots formed on the surface of Jupiter - emissions of gas and dust into the atmosphere in places where fragments burned. The spots corresponded to the size of our Earth!

Of course, comets also collided with the Earth in the distant past. It is collisions with comets, and not asteroids or meteorites, that are credited with the role of gigantic catastrophes of the past, with climate change, the extinction of many species of animals and plants, and the death of developed civilizations of earthlings. Perhaps, 14 thousand years ago our planet met with a smaller comet, but this was quite enough for the legendary Atlantis to disappear from the face of the Earth?

In recent years, reports about asteroids approaching the Earth have increasingly appeared on radio, television and in newspapers. This does not mean that there are significantly more of them than before. Modern observational technology allows us to see kilometer-long objects at a considerable distance.

In March 2001, the asteroid "1950 DA", discovered back in 1950, flew at a distance of 7.8 million kilometers from Earth. Its diameter was measured to be 1.2 kilometers. Having calculated the parameters of its orbit, 14 reputable American astronomers published the data in the press. In their opinion, on Saturday March 16, 2880, this asteroid may collide with the Earth. There will be an explosion with a power of 10 thousand megatons. The probability of a disaster is estimated at 0.33%. But scientists are well aware that it is extremely difficult to accurately calculate the orbit of an asteroid due to unforeseen influences on it from other celestial bodies.

In early 2002, a small asteroid "2001 YB5" with a diameter of 300 meters flew at a distance twice the distance from the Earth to the Moon.

On March 8, 2002, the small planet “2002 EM7,” 50 meters in diameter, approached the Earth at a distance of 460 thousand kilometers. She came to us from the direction of the Sun, and therefore was invisible. It was noticed only a few days after it flew past the Earth.

Reports about new asteroids passing relatively close to the Earth will continue to appear in the press, but this is not the “end of the world,” but ordinary life in our solar system.

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A presentation on the topic “Asteroid Threat” (grade 11) can be downloaded absolutely free on our website. Project subject: Astronomy. Colorful slides and illustrations will help you engage your classmates or audience. To view the content, use the player, or if you want to download the report, click on the corresponding text under the player. The presentation contains 16 slide(s).

Presentation slides

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Asteroid threat

THREAT TO EARTH

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The White Sands Missile Range in the US state of New Mexico is a closed military base - an Air Force test laboratory with eight telescopes pointing to the sky. Two of them serve defense purposes, but not quite in the usual sense of the word: they “care” not about the defense of the United States, but about all of humanity. Night after night, when visibility allows, scientists scan the skies for asteroids and comets that might appear near Earth. They are quite successful in this: by the beginning of September 2001, more than 700 near-Earth asteroids and several comets were discovered here. “Since we took on this task in 1998,” says astronomer Grant Stokes proudly, “70 percent of the ‘near-Earth objects’ seen around the world have been discovered by us.” Grant Stokes directs the Near-Earth Asteroid Search (LINEAR) program, a collaboration between MIT's Near-Earth Asteroid Research Laboratory and the Air Force. The secret of success is, first of all, a special chip, measuring ten by ten centimeters, which perceives the light of the stars captured by the telescope and transmits the image to the computer. The advantages of the microcircuit include the incredible speed of image transfer. Much more impressive is what you can see in an office filled with monitors. The screens shimmer with many luminous points of the night sky over New Mexico, caught in the telescope lens.

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Are there near-Earth objects among them? LINEAR employee Frank Shelley can quickly detect them with the press of a few keys using a computer. “We take five pictures of each area, 30 minutes apart. The computer compares the photos. He sifts out everything that has remained in its place during this time, namely distant fixed stars." What remains are celestial bodies that are close enough to the Earth for their movement to be noticeable in the photographs: these are the desired near-Earth objects, as well as asteroids , which revolve around the Sun in the asteroid belt between the orbits of Mars and Jupiter. Asteroids marked in green are precisely from this belt; they do not pose a danger to the inhabitants of the earth. And red means: “Attention! A near-Earth object!” to the Earth, or a near-Earth asteroid. Comets are much less common.

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“Near-Earth asteroids usually do not pose any danger. But from time to time, such a celestial body may find itself at too close a distance from the Earth or even rush directly towards it. Humanity should have the opportunity to protect itself from a possible collision with a cosmic body, therefore We strive to predict developments as early as possible." In the 1998 blockbuster Armageddon, preventing the end of the world was easy. A gigantic asteroid, the size of Texas, was rushing at a speed of 35 thousand kilometers per hour towards 3 Earth. In just 18 days remaining before the disaster, a team of drilling specialists completed astronaut courses, mastered the Space Shuttle, drilled a hole 255 meters deep in the asteroid and split it into two parts with an atomic bomb. The halves flew past the Earth, and humanity was saved.

Hollywood Armageddon and the real threat

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This scenario has nothing to do with reality. The celestial bodies that Earth may collide with are significantly smaller than the monster from Armageddon, however, securing them is much more difficult than described in the film. But even weaker attacks from space put life on Earth on the brink of destruction. An asteroid with a diameter of only 10-15 kilometers is not unreasonably accused of having destroyed 75-80 percent of animal and plant species, in particular dinosaurs, 65 million years ago. It punched a crater with a diameter of two hundred kilometers, one half of which is located on the Mexican Yucatan Peninsula, the second in the Gulf of Mexico. Billions of tons of dust and water vapor, soot and ash from the monstrous fire obscured the sun for many months; this could lead to a catastrophic drop in temperature on the surface of the earth for all living things.

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Numerous craters on all continents indicate that the earth has been constantly bombarded from space throughout its history. Nowadays, about 150 such giant craters have been found. It is absolutely clear that these are not traces of all the collisions that our planet has experienced. In many inaccessible regions, the search for meteorite craters has not yet been carried out. It is very difficult or almost impossible to determine the areas where celestial bodies fall due to deformation of the earth's crust, geological sediments and soil erosion. But the main thing is that it is extremely difficult to detect traces of impact in the oceans, which cover 70 percent of the Earth's surface. The few craters that have been discovered to date are located on flat continental shelves. We can speak with confidence about only one place where a celestial body fell in the water depths - in the eastern part of the Pacific Ocean, west of Cape Horn.

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In this very area, as studies conducted in 1995 by an international expedition on the German research vessel Polarstern showed, an asteroid fragment measuring one to four kilometers in size collapsed 2,150,000 years ago. Researchers with Polarstern, “scanning” the seabed with the help of echo sounders, discovered an area more than a hundred kilometers long, dotted with deep, 20-40 meters, grooves; however, no crater was observed. Nevertheless, asteroid particles were found in bottom sediments that settled in a characteristic sequence. “Thanks to these findings,” says expedition scientific director Rainer Gerzonde from the Alfred Wegener Institute for Marine and Polar Research, “we now know at least what we should be looking for in the depths of the ocean.” Modeling of the fall of celestial bodies into the depths of the ocean shows that it causes the same fatal consequences as impacts on land. Huge masses of hot water vapor and salt, and fragments of stones were thrown into the upper layers of the atmosphere; Giant waves emanated from the epicenter of the fall. If after the fall of the celestial body their height reached 20-40 meters, then two-hundred-meter monsters - destroyers - fell on the shores.

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Wanderers of the Universe Asteroids: celestial bodies with a diameter of 1 to 1000 kilometers, like planets, revolve around the Sun. Most of this mostly rocky debris swirls in the asteroid belt between the orbits of Mars and Jupiter. However, some break through the orbit of Mars into the inner part of the solar system relative to the orbit of Earth; individual bodies can collide with the Earth while passing through its orbit. Comets: small celestial bodies with a huge shell of gas and a tail that stretches for millions of kilometers. The core consists of a mixture of frozen solids, water and gases. Many comets penetrate into the inner part of the Solar System and can be dangerous for our planet.

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Meteors (shooting stars): A light phenomenon in the sky that occurs when small particles of material from space burn up in the atmosphere near Earth. Meteorites: celestial bodies made of stone or iron, or both, that fell to the surface of the Earth. Mostly asteroid debris. Potentially Hazardous Asteroids: “not potentially hazardous asteroids,” celestial bodies with a diameter of 150 meters or more, approaching Earth closer than 7,500,000 kilometers. Near-Earth Asteroids: "near-Earth asteroids" that have crossed the orbit of Mars and come within a relatively close distance of Earth.

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Using the new telescope, astronomers will track small cosmic bodies that, when falling to Earth, threaten to destroy an entire city. In addition, it is planned to search for exploding stars and analyze the properties of dark matter.

Earth arms itself against a threat from space

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Asteroids less than a kilometer in diameter are unlikely to cause catastrophic climate change or even the loss of humanity, but they can cause widespread destruction and millions of deaths if they hit a large city. The last known case took place in Siberia. The Tunguska meteorite, which fell in 1908, did not lead to large casualties and destruction due to the sparse population of this area. At the same time, the fall of this cosmic body into a more urbanized area could have dramatic consequences. Pan-Starrs is planned to use four 1.8-meter telescopes. The first prototype of the PS1 telescope has already been installed on the Halekala volcanic peak in Hawaii.

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In 1994, Comet Shoemaker struck Jupiter, the largest planet in the solar system. Levy 9. If this comet fell to Earth, the effect of the fall would be equal to the explosion of 1 million hydrogen bombs with a yield of 1 megaton. Dan Peterson observed the gas giant using a twelve-inch amateur telescope. On Monday, at 11:15 GMT, he detected a flash on Jupiter, which he said lasted about 1.5-2 seconds. At that moment, the amateur was unable to capture the unusual phenomenon on a video camera. However, he reported it to other enthusiasts, one of whom, George Hall, made automatic recordings from his telescope and published a corresponding video

There are hypotheses that a collision with a giant asteroid led to a fragment breaking off from the Earth from which the Moon was formed, and the Pacific Ocean arose at the site of the collision.

Collisions with giant asteroids should lead to the destruction of all life on Earth. If humanity is waiting for the Apocalypse (the end of the world), then this could be a collision of the Earth with a giant asteroid, or several asteroids.

The urgency of the problem of asteroid danger after the Chelyabinsk (Chebarkul) meteorite became obvious to everyone. With all the troubles associated with this small meteorite measuring 15–17 m and weighing about 10 thousand tons, which exploded on February 15 at 9.20 am over a densely populated area of the Chelyabinsk region, we should be grateful to it. He fulfilled his educational mission: at one time the population of the planet witnessed this event and, through its consequences, realized the threat of an asteroid danger.

And this is not an exaggeration: the fall of the Chebarkul meteorite released an energy of about 20 kilotons, which is comparable to the power of the bombs dropped on Hiroshima and Nagasaki. One can imagine what would have happened if asteroid 2012 DA 14 with a diameter of 44 m and a mass of 130 thousand tons had fallen on the city, which passed 11 hours after the Chebarkul one, below geostationary orbit at a distance of about 27 thousand km from the Earth.

The problem of the asteroid-comet hazard is complex; it can be divided into three components: detection of all dangerous near-Earth bodies (NEBs), determination of the degree of threat with risk assessment, and counteraction in order to reduce damage. Meteor showers rain down on the Earth all the time - from micron-sized dust particles to meter-long bodies. Larger ones fall much less often. For example, meteorite bodies ranging in size from 1 to 30 m - with a frequency of once every few months, more than 30 m with an interval of approximately once every 300 years. If the diameter is more than 100 m, this is a regional catastrophe, more than 1 km is a global catastrophe, and fatal consequences for civilization can occur in a collision with bodies more than 10 km.

The problem of asteroid danger was discussed at a conference held in Snezhinsk in 1994, where the American Edward Teller, the creator of the hydrogen bomb, who was a passionate promoter of protecting the Earth from asteroids, flew in. But then an international team of scientists came to the conclusion that if the size of the asteroid exceeds 5 km, it will have kinetic energy equal to millions of megatons, and it is almost impossible to create a missile with a nuclear charge to protect against it. Many other methods are offered today. Edward Teller

As NASA Administrator Charles Bolden said, according to the task set by the US President, their new project involves capturing a 500-ton asteroid about 7 m in size and towing it into lunar orbit or to the Lagrange point of the Moon-Earth system. In the future, by 2025, an expedition to this asteroid is proposed with astronauts visiting it to study it.

Over the past 200 years, 35 thousand asteroids have been discovered, numbered and registered at the Minor Planet Center, which has been keeping records of all known small celestial bodies since 1946. Here are objects approaching the Earth (NEOs, Near Earth Objects), whose orbits pass at a distance from the Earth less than 0.3 AU. e. (45 million km). Among them are potentially dangerous objects (POO, Potentially Hazardous Objects), which cross the Earth's orbit within 0.05 AU. e. (7.5 million km). As of February 2013, more than 9,624 NEOs were cataloged, of which 1,381 were NEOs, including 439 of the most dangerous ones, which pass between the Moon and the Earth. They may collide with Earth within the next 100 years. Bodies from 5 to 50 m make up 80% of them.

Today, work on the detection of NEOs and their cataloging is most organized and research is developed in the United States, where the state provides annual funding for this work. Already in 1947, the United States was forced to address the problem of asteroid-comet danger and begin to create the Minor Planet Center under the auspices of the International Astronomical Union, which became the leading organization for the detection of asteroids, comets and minor planets of the Solar System, which is located at the Smithsonian Astrophysical Observatory in Cambridge (State). Massachusetts) and funded by NASA

As for the research of asteroids and comets by spacecraft, we have to admit that after the success back in 1984 of the Soviet interplanetary spacecraft Vega-1 and Vega-2, which flew around Halley’s comet at a distance of 10 and 3 thousand km, we have no more achievements was. However, over the past time, the Galileo space station (USA) has photographed the large asteroid Ida (58 x 23 km) and discovered its satellite Dactyl (1.4 km) for the first time; The NEAR station determined the composition and constructed a map of the asteroid Eros (41 x 15 x 14 km), made a soft landing on its surface and determined the composition of the soil to a depth of 10 cm.

Space protection of the Earth from asteroids with a diameter of less than 1 kilometer can be created in the next 10 years. The exploration of deep space will make it possible to create protection against asteroids with a diameter of up to 10 km. The accumulated nuclear missile weapons make this possible.

Humanity, having created nuclear missile weapons, has received the only opportunity to combat the asteroid danger. Russian scientists have already proposed using nuclear weapons either to destroy asteroids or to divert them from Earth's orbit.

Asteroid falls are a problem that threatens the safety of civilization; it is impossible to predict which country they will fall on. The Chebarkul meteorite shook the world and showed that we assess cosmic threats in a down-to-earth way and will not be able to successfully combat them, since this requires the consolidated efforts of the entire world community. Therefore, the problem from a scientific, technical, economic, military one grows to a political one on a global scale. If we are unable to look at this problem from cosmic heights and build interstate relations on this basis, then the prospect for us is gloomy - sooner or later a global disaster may overtake us.