Research project on the topic: "Asteroid danger." Presentation on the topic “asteroid safety of the earth” Thank you for your attention
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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, 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.
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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 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.
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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 atomic bomb into two parts. 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. The areas of fall of celestial bodies are very difficult or almost impossible to determine due to deformation 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 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 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.
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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 orbit of Earth solar system; 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): light phenomenon in the sky, which occurs when small particles of matter 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 with a diameter of less than a kilometer are unlikely to lead to catastrophic climate change or even the death of humanity, but they can cause massive destruction and millions of deaths if they hit Big City. The last known case took place in Siberia. 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.
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 record unusual phenomenon to 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 Chelyabinsk region, we should be grateful to him. 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 hydrogen bomb, who was a passionate advocate for protecting the Earth from asteroids. 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 hazard 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. Accumulated missile nuclear weapon allows this to happen.
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.
Polytechnic Museum October 10, 2008 Asteroid-comet hazard Boris Shustov Institute of Astronomy RAS On the agenda: 7. Space debris - 4 days 12. Near-Earth objects - 4 days http://www.unoosa.org/oosa/en /COPUOS/stsc/2008/presentations.html Lecture plan What is AKO Historical evidence The problem of AKO - current state Directions of work About methods of counteraction Immediate tasks 2. What is AKO? Small bodies of the Solar System Dust grains up to ~ 1 mm Meteoroids up to ~ (10 -) 100 m Asteroids more than ~ (10 -) 100 m Comets presence of ice No strict definitions! Position of asteroids and comets in the Solar System Comets Main asteroid belt Near Earth Asteroids (NEA) Movement of small bodies in the Solar System Near Earth objects, potentially dangerous objects, threatening objects Near Earth Objects (NEO) ) - asteroids and comets whose orbits have perihelion distances q< 1.3 а.е. Потенциально опасные объекты (ПОО, Potentially Hazardous Objects) - тела, чьи орбиты в настоящую эпоху сближаются с орбитой Земли до минимального расстояния, не превышающего 0.05 а.е. (7.5 млн. км). Для ПОО принимают, что абсолютная астероидная звездная величина Н 22. Угрожающие объекты – тела, имеющие весомую вероятность столкновения с Землей. Туринская шкала АКО Количество известных ОСЗ и ПОО По состоянию на 26 июня 2008 г. Всего объектов, сближающихся с Землей (ОСЗ) – 5515 , в т.ч. 5465 АСЗ и 65 комет Из них потенциально опасных объектов - 959 Результат падения крупного тела в океан, 2D расчет. Объект Размеры Частота (раз в … лет) Размер кратера (км) Результат столкновения с Землей Пылинка D < 0.1 см Сгорает Метеороид 0.1 см < D < 0.5 м Сгорает 0.5 м < D < 2030 м Долетают до Земли с малой скоростью > 30 m 250 No > 0.5 Tunguska Event Type Asteroid Arizona Crater > 100 m 5 thousand >2 Regional catastrophe > 1 km 600 thousand > 20 Global catastrophe 10 km 100 million 200 End of civilization Concept of asteroid-comet danger Asteroid-comet danger - threat causing serious damage to humanity as a result of collisions of cosmic bodies larger than several tens of meters (i.e., asteroids and comets) with the Earth. 3. Historical evidence Arizona crater (Barringer crater, Devil's Canyon) Age about 50 thousand years. Diameter 1240 m, depth 170 m. The result of a fall of a body measuring 60 m (300 thousand tons) at a speed of 20 km/s. Explosion power 20 million tons of TNT. Fragments of meteorite nickel iron were found inside and around the crater. Large meteorite craters on the territory of Russia Name of crater Popigai Kara Puchezh-Katunksky Kamensky Logancha Elgygytgyn Kaluzhsky Yanisyarvi Karlinsky Coordinates latitude longitude 71°38" 111°11" 69°06" 64°09" 56°58" 43o43" 48°21" 40° 30" 65°31" 95°56" 67°30" 172°05" 54°30" 36°12" 61°58" 30°55" 54°55" 48°02" Diameter, km Age, million years 100 65 ? 80 25 20 18 15 14 10 35.7 ± 0.2 70.3 ± 2.2 167 ± 3 49.15 ±0.18 40 ±20 3.5 ± 0.5 380 700 ± 5 5±1 Recent evidence of large body collisions Astronomical: Comet Shoemaker-Levy 9 collision with Jupit er in 1994 Terrestrial: Tunguska catastrophe An image of asteroid 2007 WD5 taken with the 2.2 m telescope at the University of Hawaii. (Credit: Tholen, Bernardi, Micheli) To the 100th anniversary of the fall of the Tunguska meteorite (06/30/1908) Date: June 26-28, 2008 Venue: Moscow, Leninsky Prospekt, 32a Conference organizers: Russian Academy of Sciences Moscow State University. M.V. Lomonosov, http://tunguska.sai.msu.ru/index.php 4. The ACO problem – the current state The increase in the number of known NEAs How many unaccounted for, potentially dangerous objects? Scores: > 2,104 (> 140 m) > 2,105 (> 50 m) Search programs Lincoln Near-Earth Asteroid Research (LINEAR) Near-Earth Asteroid Tracking (NEAT) Spacewatch Lowell Observatory Near-Earth Object Search (LONEOS) Catalina Sky Survey Japanese Spaceguard Association (JSGA) Asiago DLR Asteroid Survey (ADAS) The Space Guard program, whose main goal is to detect 90% of asteroids larger than 1 km in size, is close to being completed in 2008. But this is absolutely not enough! The most dangerous on a time scale of 105 years Considering the frequency of falls of bodies of various sizes, the possible number of victims and associated material damage, on a time scale of 105 years the greatest losses on land are expected from falling bodies measuring ~ 50-100 m, when falling into the ocean - from falling bodies ~ 200 m. Close passages of asteroids Number (99942) (85640) (35396) Date of approach Distance, a.u. Apophis 2029 Apr. 13.91 0.0002318 2005 YU55 2011 Nov. 8.98 0.001065 2000 WO107 2140 Dec. 1.82 0.001623 2001 WN5 2028 June 26.23 0.001670 1998 OX4 2148 Jan. 22.14 0.002004 1999 AN10 2027 Aug. 7.29 0.002654 1998 MZ 2116 Nov. 26.98 0.002750 1997 XF11 2136 Oct. 28.49 0.002762 2004 XP14 2006 July 3.18 0.002891 2003 QC10 2066 Sept.24.86 0.003396 Name 2004mn4 05/11/2005 (Observatory on Terskol Peak) Potentially dangerous object discovered in 2004 20 04 MN4=(99942) Apophis, which has a diameter of 200-350 meters, in 2029 will pass dangerously close to Earth. In 2036, it has a non-zero probability of colliding with Earth. Humanity may have the opportunity to organize active counteraction to the collision. Observations of the asteroid Apophis using Arecibo radar. Relative motion of the Earth and Apophis Observations of Apophis are possible only during short-term approaches to the Earth, subsequent with a period of ~8 years. Conditions for the approach of the asteroid Apophis 99942 to the Earth in 2029. Possible locations for the fall of the asteroid Apophis in April 2036. Apophis is not an isolated example. For asteroid 2004 VD17, the probability of a collision on May 4, 2102 is estimated at 0.001. Threat level on the Turin scale 2. In recent years, a clear understanding has emerged that a threatening object can be detected at any moment! (Comets are especially unpredictable.) Such a threat should not take humanity by surprise! 5. Directions of work Directions of work on the ACO problem Creation of a system (participation in the international system) for detecting, cataloging and monitoring NEOs; Tasks of determining the physical (including dynamic) and chemical characteristics of threatening bodies; Study of possible measures to prevent the danger of a collision of NEAs with the Earth and reduce the severity of the consequences; Coordination of actions of the international community; Basic research. Some fundamental scientific problems associated with the study of ACO How is the population of near-Earth objects reproduced? Evolution of the orbits of small bodies in the Solar System and refinement of collision forecasts; Study of the physicochemical properties of small bodies of the Solar System; Fundamental aspects of studying possible measures to prevent NEO collisions with the Earth and reduce damage. Optimal parameters of ground-based telescopes designed to detect NEOs The field of view of the instrument should be at least several square degrees; Penetration capacity is no worse than 21 – 22m (the best systems in the world are 23 – 24m; The number of clear nights with good image quality should be at least 50% per year; Powerful computer equipment and software to obtain operational information about new objects during the night and final processing before the beginning of the next night; The telescope must be operated by qualified personnel and have operational communication with other observatories. Pan-STARRS Pan-STARRS - a system of 4 telescopes Diameter - 1.8 m Field of view - 3 degrees CCD receiver - 1.4 billion pixels Resolution - 0.3 arcsec. Limit - 24 stars. value (exp. up to 60 sec) Coverage per night – 6000 sq. degrees Large Synotic Survey Telescope (LSST) - planned to be commissioned in 2012-2014. Diameter - 8.4 m Field of view - 3.5 degrees CCD receiver - 3 billion pixels Resolution - 0.3 arcsec. Limit - 24.5 stars. magnitude (exp. 15 sec) Coverage - sky for 3 nights LSST There are no specialized instruments in Russia yet. (neither in optics nor in radio bands) Space missions Near-Earth Asteroid Rendezvous (NEAR) 1996 -1998 (Eros) Deep Space 1 (DS1) 1998 -1999 (Braille, Borelli) Deep Impact 2005 (Tempel 1) STARDUST 1999 – 2004 – 2006 (Wild 2) Hayabusa (MUSES-C) 2003-200? (Itokawa) Dawn 2006 – 2010 (Vesta, Ceres) Rosetta 2004 -2008 -2010 -2014 (Stein, Lutetia, Churyumova - Gerasimenko) Marco Polo ? - NEO Don Quichote (Phase A) A mission for detection of Inner Earth Objects by means of observations from an orbiting compact satellite (Astreroid Finder) Hayabusa (Muses-C) and the Itokawa asteroid Requirements for the mission to deliver a radio beacon (transponder) to Apophis 1. Providing radio sessions throughout the entire orbit for 10 years. 2. Conducting the mission with sufficient advance notice until 2029. 3. A single radio channel for the range and all information exchange of the spacecraft. 4. Rejection of the principle of installing a beacon on the asteroid itself. 5. Placement of a radio beacon in an asteroid-centric orbit. 6. Using the reserves for the Phobos-Grunt mission (NPO Lavochkin). The goal of the project is to deliver soil samples from Phobos to Earth and conduct scientific research on Phobos and Mars. Parent organizations: For KNA - GEOKHI, IKI RAS For RKK-NPO im. S.A. Lavochkina Launch - 2009. The mass of the Phobos soil sample delivered to Earth is 0.1 kg. The duration of the flight to the sphere of influence of Mars is 850 days. The duration of the flight to Earth is 285 days. Project Phobos-Grunt 6. About methods of counteraction Possibilities of means of counteracting threatening objects Destruction (dispersion) or deviation? Rejection is preferable! Destruction is more feasible (for small bodies), but the consequences are difficult to predict. Russia, as one of the nuclear powers, possessing developed space technologies and experience in conducting space missions, cannot and should not stand aside from solving the problem under consideration. In Russia, such research is being carried out on an initiative basis. Further exchange of information is necessary. Methods of deflection (orbit change) by the kinetic impact of a massive body launched into space and colliding with an asteroid; Gravity pull; The withdrawal impulse can also be obtained using a surface or near thermonuclear explosion; Using low jet thrust, created, for example, by an electric propulsion system. Other methods Means of counteracting threatening objects Gravity tractor Immediate tasks Organizational activity 1. In February 2007, the “Expert Working Group on the Problem of Asteroid-Comet Hazard” (ERGAKO) was created under the RAS Council on Space. It included representatives of the Russian Academy of Sciences, Roscosmos, the Ministry of Emergency Situations, Rosatom, and other interested departments and organizations. 2. One of the main tasks of the group is the development of a project for the Federal Target Scientific and Technical Program “Asteroid and Comet Safety of Russia”. About the work of the Expert Working Group on the problem of ACO 1. An examination of 2 proposals was carried out. We constantly worked with the media. 2. International conferences on ACO topics were held (“Near-Earth Astronomy 2007” and “100 Years of the Tunguska Phenomenon”) 3. A draft (passport) of the Federal Target Program was prepared http://www.inasan.ru/rus/asteroid_hazard/
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Asteroid danger
An asteroid is a relatively small celestial body in the Solar System moving in orbit around the Sun. Asteroids are significantly inferior in mass and size to planets and have irregular shape and have no atmosphere.
Currently, hundreds of thousands of asteroids have been discovered in the Solar System. As of 2015, there were 670,474 objects in the database, of which 422,636 had accurately determined orbits and assigned an official number, more than 19,000 of them had officially approved names. It is estimated that there may be from 1.1 to 1.9 million objects in the Solar System that are larger than 1 km. Most currently known asteroids are concentrated within the asteroid belt, located between the orbits of Marsai and Jupiter.
Ceres, measuring approximately 975 x 909 km, was considered the largest asteroid in the Solar System, but since August 24, 2006, it received the status of a dwarf planet. The other two largest asteroids, Pallas and Vesta, have a diameter of ~500 km. Vesta is the only asteroid belt object that can be observed naked eye. Asteroids moving in other orbits can also be observed during their passage near the Earth.
The total mass of all main belt asteroids is estimated at 3.0-3.6·1021 kg, which is only about 4% of the mass of the Moon. The mass of Ceres is 9.5 1020 kg, that is, about 32% of the total, and together with the three largest asteroids Vesta (9%), Pallas (7%), Hygeia (3%) - 51%, that is, the vast majority of asteroids have an insignificant mass by astronomical standards.
However, asteroids are dangerous for planet Earth, since a collision with a body larger than 3 km can lead to the destruction of civilization, despite the fact that the Earth is much larger than all known asteroids.
Almost 20 years ago, in July 1981, NASA (USA) held the first Workshop “Collisions of Asteroids and Comets with the Earth: Physical Consequences and Humanity,” at which the problem of the asteroid-comet hazard received “official status.” From then to the present, at least 15 international conferences and meetings devoted to this problem have been held in the USA, Russia, and Italy. Realizing that the primary task of solving this problem is the detection and cataloging of asteroids in the vicinity of the Earth's orbit, astronomers in the United States, Europe, Australia and Japan began to make vigorous efforts to set up and implement appropriate observational programs.
Along with special scientific and technical conferences, these issues were considered by the UN (1995), the UK House of Lords (2001), the US Congress (2002) and the Organization for Economic Cooperation and Development (2003). As a result of this, a number of decrees and resolutions were adopted on this problem, the most important of which is Resolution 1080 “On the detection of asteroids and comets potentially dangerous to humanity,” adopted in 1996 by the Parliamentary Assembly of the Council of Europe.
It is obvious that you need to be prepared in advance for a situation where you need to make quick and error-free decisions to save millions and even billions of people. Otherwise, due to lack of time, state disunity and other factors, we will not be able to take adequate and effective measures of protection and rescue. In this regard, it would be unforgivably careless not to take effective measures to prevent such events. Moreover, Russia and other technologically developed countries of the world have all the basic technologies to create a Planetary Defense System (PPS) from asteroids and comets.
However, the global and complex nature of the problem makes it impossible for any single country to create and maintain such a protection system in constant readiness. It is obvious that since this problem is universal, it must be solved by the joint efforts and means of the entire world community.
It should be noted that in a number of countries certain funds have already been allocated and work has begun in this direction. At the University of Arizona (USA), under the leadership of T. Gehrels, a technique for monitoring NEAs has been developed and since the late 80s, observations have been carried out using a 0.9-m telescope with a CCD matrix (2048x 2048) at the Kitt Peak National Observatory. The system has proven its effectiveness in practice - about one and a half hundred new NEAs have already been discovered, with sizes up to several meters. To date, work has been completed to transfer the equipment to the 1.8-m telescope of the same observatory, which will significantly increase the rate of detection of new NEAs. Monitoring of NEAs has begun under two more programs in the United States: at the Lovell Observatory (Flagstaff, Arizona) and in the Hawaiian Islands (a joint NASA-US Air Force program using the 1-m Air Force ground-based telescope). In the south of France, at the Côte d'Azur Observatory (Nice), the European NEA Monitoring Program has been launched, in which France, Germany and Sweden are involved. Similar programs are also being staged in Japan.
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.
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. celestial asteroid Tunguska
Tunguska phenomenon
Two large celestial bodies fell to Russian Earth in the 20th century. Firstly, 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 an explosion, it is equated by its destructive effect on environment 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 a 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.” Opinions about the nature of the Tunguska 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.
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 Tunguska 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 with 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. There is no guarantee that the same changes in nature will not occur after an asteroid falls on Earth.
Due to the fact that there is a possibility of asteroids falling to the ground, it is necessary to create a protective installation, which should consist of two automated devices:
A tracking device for asteroids approaching the Earth;
A coordination center on earth that will control missiles to fragment the asteroid into smaller parts that cannot harm nature or humanity. The first should be a satellite (ideally several satellites) located in the orbit of our planet and constantly monitoring celestial bodies flying by. When a dangerous asteroid approaches, the satellite must transmit a signal to a coordination center located on Earth.
The center will automatically determine the flight path and launch a rocket that will break a large asteroid into smaller ones, thereby preventing a global catastrophe in the event of a collision.
That is, it is necessary for scientists to develop specific automated mechanisms that will control the movement of celestial bodies, and in particular those approaching our planet, and prevent global catastrophes.
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 to solve this problem 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 space or, in other words, we have a chance to protect ourselves from collisions with dangerous space objects. 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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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. Last years On radio, television and in newspapers, reports about asteroids approaching the Earth are increasingly appearing. 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 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. You can arrange a contact nuclear explosion on a 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 better Sun rays. 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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