Slide 1
Slide 2
Slide 3
Slide 4
Slide 5
Slide 6
Slide 7
Slide 8
Slide 9
Slide 10
Slide 11
Slide 12
Slide 13
Slide 14
Slide 15
Slide 16
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
Slide 1
Asteroid threat
THREAT TO EARTH
Slide 2
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, ten by ten centimeters in size, 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.
Slide 3
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 just from this belt, they do not pose a danger to the inhabitants of the Earth. And red means: “Attention! Near-Earth object!”. Often this is an asteroid that has come too close to the Earth, or a near-Earth asteroid.Comets are much less common.
Slide 4
“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
Slide 6
Slide 8
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.
Slide 9
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. The areas where celestial bodies fall are very difficult or almost impossible to determine 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.
Slide 10
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 grooves of 20-40 meters; 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, 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.
Slide 11
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.
Slide 12
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.
Slide 13
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
Slide 15
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.
1 of 20
Presentation on the topic: Asteroid safety of the earth
Slide no. 1
Slide description:
Slide no. 2
Slide description:
Today we will learn: What is an asteroid. What collisions of the Earth with smaller celestial objects have occurred. What are Star Wounds? Why do global catastrophes happen every 30 million years? What asteroids are known in Russia? What is the Tunguska phenomenon? What were the meteorites of the 20th century? What can happen due to a collision with a comet. What are asteroids like today? What kind of protection does the Earth have from bombardment from space? Tracking celestial bodies. Protection Options.
Slide no. 3
Slide description:
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 ἀστεροειδής - “like a star”, from ἀστήρ - “star” and εῖ δος - “appearance, appearance, quality”) was introduced by William Herschel on the basis that these objects looked like when observed through a telescope like points of stars - in contrast to planets, which look like disks when observed 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
Slide no. 4
Slide description:
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 from comets) continuously fall to the Earth.
Slide no. 5
Slide description:
“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 formed when the Earth collided with a body of forty meters in diameter.
Slide no. 6
Slide description:
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.
Slide no. 7
Slide description:
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 36-37 million 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.
Slide no. 8
Slide description:
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.”
Slide no. 9
Slide description:
Slide no. 10
Slide description:
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!
Slide no. 11
Slide description:
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. According to them, 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.
Slide no. 12
Slide description:
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 over the same period at approximately 2.5%.
Slide no. 13
Slide description:
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.
Slide no. 14
Slide description:
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.
Slide no. 15
Slide description:
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.
Slide no. 16
Slide description:
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. 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.
Slide no. 17
Slide description:
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. 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.
Slide no. 18
Slide description:
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.
Slide no. 19
Slide description:
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.
Slide no. 20
Slide description:
Slide 2
Today we will learn:
- What is an asteroid?
- What collisions of the Earth with smaller celestial objects have occurred.
- What are Star Wounds?
- Why do global catastrophes happen every 30 million years?
- What asteroids are known in Russia?
- What is the Tunguska phenomenon?
- What were the meteorites of the 20th century?
- What can happen due to a collision with a comet.
- What are asteroids like today?
- What kind of protection does the Earth have from bombardment from space?
- Tracking celestial bodies.
- Protection Options.
Slide 3
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 ἀστεροειδής - “like a star”, from ἀστήρ - “star” and εῖ̓δος - “appearance, appearance, quality”) was introduced by William Herschel on the basis that these objects, when observed through a telescope, looked like points of stars - in contrast to planets, which look like disks when observed 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
Slide 4
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 from comets) continuously fall to the Earth.
Slide 5
"Star Wounds"
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 formed when the Earth collided with a body of forty meters in diameter.
Slide 6
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 have 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.
Slide 7
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 36-37 million years,
2. Puchezh-Katunskaya - with a crater of 80 km, whose age is estimated at 180 million years,
3. Kara - with a diameter of 65 km and age - 70 million years.
Slide 8
Tunguska phenomenon
The Tunguska 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 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.”
Slide 9
Meteorites of the 20th century
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.
Slide 10
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!
Slide 11
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. According to them, 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.
Slide 12
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 over the same period at approximately 2.5%.
Slide 13
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.
Slide 14
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.
Slide 15
Protection 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.
Slide 16
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 safe 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, burning up in the atmosphere.
Slide 17
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.
Slide 18
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.
Slide 19
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.
Slide 20
Thank you for your attention
Presentation prepared by: Denis Polikarpov. 205 group.
View all slides
Slide 1
Slide description:
Slide 2
Slide description:
Slide 3
Slide description:
Slide 4
Slide description:
Slide 5
Slide description:
“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 formed when the Earth collided with a body of forty meters in diameter.
Slide 6
Slide description:
Slide 7
Slide description:
Slide 8
Slide description:
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.”
Slide 9
Slide description:
Slide 10
Slide description:
Slide 11
Slide description:
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. According to them, 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.
Slide 12
Slide description:
Slide 13
Slide description:
Slide 14
Slide description:
Slide 15
Slide description:
Slide 16
Slide description:
Slide 17
Slide description:
Slide 18
Slide description:
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.
Slide 19
Slide description:
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.
Slide 20
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. According to them, 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 over 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.
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.
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.
