Near Earth asteroids ( Near-Earth asteroids are asteroids with perihelion distances less than or equal to 1.3 AU. e .. Those of them that in the foreseeable future can approach the Earth at a distance less than or equal to 0.05 a. e. (7.5 million km), and have an absolute magnitude not weaker than 22m, are considered potentially dangerous objects.

A huge number of comets and asteroids move in the solar system. Most of them (more than 98%) are concentrated in the main asteroid belt (located between the orbits of Mars and Jupiter), the Kuiper belt and the Oort cloud (the existence of the latter is still confirmed only by indirect data). Periodically, some objects in these regions, as a result of collisions with neighbors and/or under the influence of gravity of larger objects, leave their usual orbits and can be directed, including towards the Earth.

There are also many asteroids orbiting the Sun closer than the main belt. Those that approach the Earth, depending on the parameters of the orbit, are assigned to one of the following four groups (traditionally called by the name of the first open representative):

cupids(in honor of the asteroid (1221) Amur) - asteroids whose orbits lie entirely further from the Sun than the earth's aphelion. In total, at the moment (March 2013), the presence of 3653 asteroids of this group is known, of which 571 are assigned sequence numbers, and sixty-five have proper names. Cupids, like other representatives of near-Earth asteroids, are relatively small in size - only four cupids with a diameter of more than 10 km are known.

Apollos(in honor of the asteroid (1862) Apollo) - asteroids whose perihelion is closer to the Sun than the earth's aphelion, but the semi-major axis of their orbit is larger than the earth's. Thus, in their movement, they do not just pass near the earth's orbit, but cross it (from the outside). In total, at the moment (March 2013) the presence of 5229 asteroids of this group is known, of which 731 are assigned serial numbers, and sixty-three have their own names. This is much more than that of related asteroids from the Aton group. This is the most numerous type of near-Earth asteroids. Such a large difference in the number of asteroids is explained by the fact that they are most of the time beyond the Earth's orbit and can be observed at night. Given the small size of these bodies (the largest is only 8.48 km), it is much easier to detect them at night against a dark sky than the asteroids of the Atira or Aten group, which appear above the horizon only shortly before dawn or immediately after sunset and are easily lost in it. rays against the still bright sky.

Atons(in honor of the asteroid (2062) Aton) - asteroids, whose aphelion is farther from the Sun than the earth's perihelion, but the semi-major axis of their orbit is less than the earth's. They cross the earth's orbit from the inside. In total, at the moment (September 2012), the presence of 758 asteroids of this group is known, of which 118 are assigned serial numbers, and nine have their own names.

Athyra(in honor of the asteroid (163693) Atira) - asteroids whose orbits lie entirely closer to the Sun than the Earth's perihelion. In total, as of October 2014, only 14 asteroids are known to have orbits inside the Earth's orbit. Such a small number of asteroids in this group is primarily due to the difficulties of detecting and observing these bodies, as well as their small size. The fact is that since these bodies are located inside the earth's orbit, for an earthly observer they never depart from the Sun at a significant angle and, therefore, are constantly lost in the rays of the luminary. Because of this, their observation is possible only at dusk, in a short period of time shortly before dawn or immediately after sunset in a bright sky, in which it becomes very difficult to distinguish any celestial objects. At the same time, the smaller the semi-major axis of the asteroid's orbit, the smaller the angle it moves away from the Sun, the brighter sky at the moment of its appearance above the horizon, and the more difficult the observation conditions. That is why there is still no data on asteroids moving inside the orbit of Venus or, especially, Mercury (volcanoids).

Closest to the Earth were small (one to several meters in diameter) asteroids 2008 TS26 - up to 6150 km on October 9, 2008, 2004 FU162 - up to 6535 km on March 31, 2004, 2009 VA - up to 14,000 km on November 6, 2009.

Some of the smaller asteroids (such as the meter-long 2008 TC3) enter the Earth's atmosphere as meteoroids, similar to meteors.

A few interesting examples:

(433) Eros(ancient Greek Ἔρως) is a near-Earth asteroid from the Amur group (I), belonging to the light spectral class S. It was discovered on August 13, 1898 by the German astronomer Karl Witt at the Urania Observatory and named after Eros, the god of love and the inseparable companion of Aphrodite , according to ancient Greek mythology. This is the first discovered near-Earth asteroid.

It is interesting primarily because it became the first asteroid to have artificial satellite, which on February 14, 2000 was the NEAR Shoemaker spacecraft, which a little later made the first landing on an asteroid in the history of space exploration.

Rotation of the asteroid Eros. Taken on February 14, 2001 from low orbit by the NEAR Shoemaker spacecraft:

Asteroid Eros crosses the orbit of Mars and approaches the Earth. In 1996, the results of calculations of the dynamical evolution of the orbit of Eros over 2 million years were published. Eros is found to be in orbital resonance with Mars. Orbital resonance with Mars can shift the orbits of asteroids that cross the orbit of Mars, such as Eros, so that they cross the Earth's orbit. As part of the study, out of 8 initial orbits similar to the orbit of Eros, 3 evolved so that they began to cross the Earth's orbit during the specified 2 million years. One of these orbits leads to a collision with the Earth after 1.14 million years. Although according to these calculations there is no significant danger of Eros colliding with the Earth in the next 105 or so years, such a collision is likely in the distant future.

Animation of rotation of the asteroid Eros

Eros is a relatively large asteroid, which is the second largest near-Earth asteroid in size, second only to the asteroid (1036) Ganymede. It is believed that the impact potential of Eros if it hit Earth would be greater than that of the asteroid that formed the Chicxulub crater, causing the K-T extinction event that wiped out the dinosaurs on Earth.

As is known, gravity on the surface is inversely proportional to the distance to the center of mass of the body, which in Eros, as well as in most other asteroids, varies greatly due to their irregular shape: the larger the radius (with the same mass), the less gravity on its surface. Eros has a strongly elongated shape, close to the shape of a peanut. Thus, at different points on the surface of Eros, the values ​​of the free fall acceleration can vary greatly with respect to each other. This is greatly facilitated by the forces of centripetal acceleration resulting from the rotation of the asteroid, which significantly reduce the attraction to the surface in extreme points asteroid farthest from the center of mass.

The irregular shape of the asteroid also has a certain effect on the temperature regime of the surface, but the main factors affecting the temperature of the asteroid are still its distance from the Sun and the composition of the surface, which determines the percentage of reflected and absorbed light. Thus, the temperature of the illuminated part of Eros can reach +100 °C at perihelion, and the unlit part can drop to −150 °C. Due to the elongated shape of Eros, it becomes possible for a small torque to appear under the influence of the YORP effect. However, due to the large size of the asteroid, the influence of the YORP effect is extremely insignificant and in the foreseeable future is unlikely to lead to any noticeable change in the rotation of the asteroid. The fairly high density of surface rocks of Eros for an asteroid, which is about 2400 kg / m³, which corresponds to the density of the earth's crust, allows Eros to maintain integrity despite a relatively fast rotation (5 hours 16 minutes).

Crater on the surface of Eros, 5 km in diameter

An analysis of the distribution of large stones on the surface of the asteroid (433) Eros allowed scientists to conclude that most of them were ejected from a crater formed about 1 billion years ago as a result of a large meteorite falling on Eros. Perhaps as a result of this collision, 40% of the surface of Eros is devoid of craters with a diameter of less than 0.5 km. Initially, it was believed that the rock fragments ejected from the crater during the collision simply filled the smaller craters, which is why they cannot be seen now. An analysis of crater density indicates that areas of lower crater density are up to 9 km away from the impact point. Some zones of low crater density are found on the opposite side of the asteroid, also within 9 km.

It is assumed that the seismic shock waves generated at the time of the collision passed through the asteroid, destroying small craters and turning them into rubble.

Already, asteroids are being considered as potential sources of resources. Based on the data obtained from the NEAR Shoemaker, the American David Whitehouse made interesting calculations about the possible "value" of this asteroid in the event of mining on it. So, it turned out that Eros contains a large number of precious metals, with a total value of at least 20 trillion dollars. This allowed us to look at the asteroid from a different point of view.

In general, the composition of Eros is similar to the composition of stone meteorites falling to Earth. This means that it contains only 3% of metals. But at the same time, these 3% of aluminum alone contain 20 billion tons. It also contains such rare metals as gold, zinc and platinum. 2900 km³ of Eros contains more aluminum, gold, silver, zinc and other non-ferrous metals than have been mined on Earth in the entire history of mankind. At the same time, Eros is far from the most large asteroid.

All these figures are just guesses, but they show how great economic potential the resources of the solar system can have, for all their immensity.

Since Eros belongs to the Amur group, it periodically approaches the Earth at a fairly close distance. So, on January 31, 2012, Eros flew at a distance of approximately 0.179 AU. e. (26.7 million km) from the Earth, which corresponds to 70 distances from the Earth to the Moon, while its apparent brightness will reach + 8.5m. But since its synodic period is 846 days and is one of the longest among all the bodies of the solar system, such encounters occur no more than once every 2.3 years. And during the closest approaches, which happen even less often, about once every 81 years (the last was in 1975, and the next will be in 2056), the apparent brightness of the asteroid Eros will be almost + 7.0 m at all - this is more than the brightness Neptune, as well as any other main belt asteroid, with the exception of such large asteroids as (4) Vesta, (2) Pallas, (7) Iris.

Eccentricity - 0.22; Perihelion - 169.569 million km; Aphelion - 266.638 million km; Period of circulation - 1.76 years; Inclination - 10.82°. Diameter -34.4×11.2×11.2×16.84 km.

View of the surface of Eros from one of its ends

The asteroid was discovered on the same evening of August 13, 1898 independently by two astronomers at once: Gustav Witt in Berlin and Auguste Charlois in Nice, but Witt was still recognized as the discovery. The asteroid was discovered by him by accident as a result of a two-hour exposure of the star Beta Aquarii while conducting astrometric measurements of the position of another asteroid, (185) Evnika. In 1902, at the Arequipa Observatory, Eros's period of rotation around its axis was determined from changes in the brightness of Eros.

As a large near-Earth asteroid, Eros played a significant role in the history of astronomy. First, during the opposition of 1900-1901, a program was launched among astronomers around the world to measure the parallax of this asteroid to determine the exact distance to the Sun. The results of this experiment were published in 1910 by the British astronomer Arthur Robert Hinks from Cambridge. A similar research program was carried out later during the 1930-1931 opposition by the English astronomer Harold Jones. The data obtained as a result of these measurements were considered final until 1968, when radar and dynamic methods for determining parallax appeared.

Secondly, it became the first asteroid to have an artificial satellite, NEAR Shoemaker (in 2000), and on which this spacecraft landed a year later.

Upon reaching Eros, the NEAR Shoemaker was able to transmit a large amount of data about this asteroid that would have been impossible or very difficult to obtain by other means. More than a thousand images of the asteroid's surface were transmitted by this device, and its main physical parameters were also measured. In particular, deviations during the flight of the apparatus near the asteroid made it possible to estimate its gravity, and, consequently, its masses, as well as to refine its dimensions.

On March 3, 2000, American Gregory Nemitz declared Eros his private property, and after the landing of the NEAR Shoemaker spacecraft on Eros, he tried to legally obtain a $20 rental fee from NASA for the use of the asteroid. However, the court dismissed his claim.

Harry Harrison's 1969 novel Captive Universe takes place inside the asteroid Eros. People live in an artificial cavity in the center of the asteroid, and the asteroid itself is transformed into a generational spaceship flying towards the planetary system of Proxima Centauri.

In a short story by Kard Orson Scott, "Ender's Game" is introduced as a former bugger stronghold for the invasion of Earth.

In the television series The Expanse, Eros, like many others, hosts a colony of prospectors. This colony was used as a biological weapons test site.

(1036) Ganymede(ancient Greek Γανυμήδης) is the largest near-Earth asteroid from the Amur group (III), which belongs to the dark spectral class S. It was discovered on October 23, 1924 by the German astronomer Walter Baade at the Hamburg Observatory and named after Ganymede, an ancient Greek youth, kidnapped by Zeus.

Due to its large size and regular approaches to the Earth, Ganymede's orbit was established with a high degree accuracy and calculate the parameters of subsequent approaches. The closest of these will occur on October 13, 2024, when Ganymede will pass at a distance of 55.9641 million km (0.374097 AU) from Earth, while its apparent magnitude can reach 8.1m. It also regularly crosses the orbit of Mars and on December 16, 2176 will have to pass at a distance of only 4.290 million km (0.02868 AU) from this planet.

Eccentricity - 0.5341189; Perihelion - 185.608 million km; Aphelion - 611.197 million km; Orbital period - 4.346; Inclination - 26.69°; Diameter - about 33 km; Albedo - 0.2926.

Since the asteroid was discovered at the beginning of the 20th century, it has a rich history of astronomical observations. Its absolute magnitude was determined back in 1931 and was equal to 9.24m, which differed very little from the results of modern observations (9.45m). The asteroid belongs to the light class S, which means it contains a large amount of iron and magnesium silicates, as well as various orthopyroxenes.

Conducted in 1998, radar observations of Ganymede using the Arecibo radio telescope made it possible to obtain images of the asteroid, on the basis of which we can talk about the spherical shape of this body. Around the same time, observations were made to obtain the light curves and polarization curves of the asteroid, but due to bad weather, these studies could not be carried out in full. Nevertheless, the obtained data allowed us to conclude that there is a weak correlation between these curves depending on the asteroid rotation angle. Since the degree of polarization depends on surface irregularities and soil composition, this indicates the relative uniformity of the asteroid surface, both in relief and in rock composition. Later observations of the light curves, carried out in 2007, made it possible to determine the period of rotation of the asteroid around its axis, which is equal to 10.314 ± 0.004 hours.

(2102) Tantalum(ancient Greek Τάνταλος) is a near-Earth asteroid from the Apollo group, which belongs to the rare spectral class Q and is characterized by a rather elongated orbit, due to which, in the process of its movement around the Sun, it crosses not only the orbit of the Earth, but also of Mars. But main feature of this asteroid is an extremely large inclination of the orbit to the plane of the ecliptic (over 64 degrees), which is a kind of record among all asteroids that have their own names.

It was discovered on December 27, 1975 by the American astronomer Charles Koval at the Palomar Observatory and was named after the character of ancient Greek mythology Tantalus, King Sipil in Phrygia.

Period of circulation: 1.5 years. Eccentricity - 0.30. Diameter - about 3 km.

(4179) Tautatis(Toutatis; transcriptions of Tutatis and Toutatis are also found in the domestic scientific literature and in the media) is an asteroid from the Apollo group approaching the Earth, whose orbit is in 3:1 resonances with Jupiter and 1:4 with the Earth.

Tautatis was first discovered on 10 February 1934 and subsequently lost. Then he was given the designation 1934 CT. The asteroid remained lost for several decades until it was rediscovered on January 4, 1989 by Christian Polla. The asteroid was named after the Celtic god Teutates.

Due to the small inclination of its orbit (0.47 °) and the short period of revolution (about 4 years), Tautatis often approaches the Earth, and the minimum possible approach distance (MOID to the Earth) at the moment is 0.006 AU. e. (2.3 times the distance to the moon). The approach on September 29, 2004 was especially close when the asteroid passed at a distance of 0.0104 AU. e. from the Earth (4 radii of the lunar orbit), giving a good opportunity for observations - the maximum brightness of the asteroid was 8.9 magnitudes.

The rotation of Tautatis consists of two different periodic motions, which makes it appear chaotic; if you are on the surface of an asteroid, it will seem that the Sun rises and sets below the horizon in random places and at random times.

Radar Tautatis using radio telescopes in Evpatoria and Effelsberg, carried out in 1992 under the direction of A. L. Zaitsev, was the first outside the United States radar of a minor planet.

Radar studies have shown that Tautatis has an irregular shape and consists of two "lobes" measuring 4.6 km and 2.4 km, respectively. There is an assumption that Tautatis was formed from two separate bodies, which at some point “merged”, as a result of which the asteroid can be compared to a “heap of stones”.

Tautatis is in 3:1 resonance with Jupiter and 1:4 with Earth. As a result, gravitational perturbations lead to the chaotic behavior of the orbit of Tautatis, which is why at the moment it is impossible to predict changes in its orbit for more than 50 years ahead.

The Earth encounter in 2004 was strong enough to raise the possibility of a collision. However, the possibility of an asteroid colliding with the Earth is extremely small.

There is a possibility that Tautatis will be thrown out of the solar system in a few tens or hundreds of years due to gravitational interactions with the planets.

The Chinese lunar probe "Chang'e-2", placed after the execution of the main program at the Lagrange point L2 of the Earth-Moon system, was redirected on April 15, 2012 to study the asteroid (4179) Tautatis.

Chang'e-2 photograph of Tautatis

On December 13, 2012, Chang'e 2 flew by the asteroid (4179) Tautatis. At 08:30:09 UTC (12:30:09 Moscow time), the spacecraft and the celestial body were separated by 3.2 kilometers. Images of the surface of the asteroid were obtained with a resolution of 10 meters.

Eccentricity - 0.62; Perihelion - 140.544 million km; Aphelion - 617.865 million km; Period of circulation - 4.036 years; Inclination - 0.44715°; Albedo - 0.13.

(1566) Icarus(ancient Greek Ἴκαρος) is a small near-Earth asteroid from the Apollo group, which is characterized by an extremely elongated orbit. It was discovered on June 27, 1949 by German astronomer Walter Baade at the US Palomar Observatory and named after Icarus, a figure in ancient Greek mythology known for his unusual death.

The asteroid has a very high orbital eccentricity (almost 0.83), due to which, in the process of its orbital movement, it significantly changes the distance from the Sun and crosses the orbits of all planets terrestrial group. Thus, Icarus lives up to its name, penetrating the perihelion of its orbit into the orbit of Mercury and approaching the Sun at a distance of up to 28.5 million km. At the same time, its surface at such a distance from the Sun heats up to a temperature of over 600 ° C. Perihelion - 27.924 million km; Aphelion - 294.597 million km; Inclination - 22.828°; Diameter - 1.0 km; Albedo - 0.51.

Between 1949 and 1968, Icarus got so close to Mercury that it changed the asteroid's orbit with its gravitational field. In 1968, Australian astronomers carried out calculations, according to which, as a result of the approach of Icarus to our planet that year, an asteroid could well have crashed to Earth in the Indian Ocean near the African coast. Fortunately, these calculations did not materialize, the asteroid passed by at a distance of only 6.36 million km. However, if he still fell to Earth, then the impact energy would be equivalent to 100 Mt of TNT.

The asteroid Icarus approaches the Earth every 9, 19 and 38 years. The penultimate time the asteroid approached in 1996 and flew at a distance of 15.1 million km. Last time was June 16, 2015 - an asteroid flew at a distance of 8.1 million km from Earth. This time he could fall in the middle Atlantic Ocean between Europe and North America. Then one fifth of the world's population could die. The next time the asteroid will approach the Earth at a comparable distance (6.5 million km from the planet) on June 14, 2090.

In the spring of 1967, a professor at the Massachusetts Institute of Technology assigned his students the task of drawing up a project for the destruction of this asteroid in the event of its imminent collision with the Earth, which became known as the Icarus Project. The first report on this project appeared in Time magazine in June 1967, and best work were published in book form a year later. this work inspired Hollywood producers to create the disaster film Meteor.

In the Soviet sci-fi film The Sky Is Calling (1959), a Soviet rescue expedition with Americans on board crash-lands on the asteroid Icarus. They are trying to help from Earth.

The American writer Arthur Clark (1960) in the science fiction story "Summer on Icarus" describes the conditions on the asteroid, where, due to a malfunction of the spacecraft, the astronaut Sherrard, a member of the expedition to study the Sun, ended up.

(3200) Phaeton(lat. Phaethon) is a small near-Earth asteroid from the Apollo group, which belongs to the rare spectral class B. The asteroid is interesting for its unusual, extremely elongated orbit, due to which, in the course of its movement around the Sun, it crosses the orbits of all four terrestrial planets from Mercury to Mars . Interestingly, at the same time, he comes close enough to the Sun, thanks to which he was named after the hero of the Greek myth about Phaethon, the son of the sun god Helios.

The peculiarity of this asteroid is also that it became the first asteroid discovered in a photograph taken from the board spaceship. Simon F. Green and John C. Davis discovered it on October 11, 1983 in images from the infrared space satellite IRAS. Its discovery was announced the next day on October 14 after being confirmed by optical observations by Charles T. Koval. The asteroid was given the temporary designation 1983 TB.

It is classified as an asteroid belonging to the Apollo group because its semi-major axis is larger than that of Earth and its perihelion is less than 1.017 AU. e. It may also be part of the Pallas family.

Perihelion - 20.929 million km; Aphelion - 359.391 million km; Period of circulation - 1.433; Inclination - 22.18°; Albedo - 0.1066.

The main feature of Phaeton is that it approaches the Sun closer than all other large asteroids of its group (the record belongs to 2006 HY51 (en: 2006 HY51)) - more than 2 times less than the perihelion of the planet Mercury, while Phaeton's speed is close to The sun can reach almost 200 km/s (720,000 km/h). And because of the record high eccentricity, close to 0.9, Phaeton, in the process of its movement around the Sun, crosses the orbits of all four terrestrial planets.

By itself, the orbit of Phaethon is more like the orbit of a comet than the orbit of an asteroid. Studies in the infrared region of the spectrum have shown that its surface consists of solid rocks, and, despite the high temperatures of ~1025 K, during the entire period of observation, it has never managed to fix the appearance of a coma, a tail, or any other manifestations of cometary activity. . Despite this, soon after its discovery, Fred Whipple noted that the elements of the orbit of this asteroid almost coincide with the orbital parameters of the Geminid meteor shower. In other words, the asteroid may be the source of the Geminid meteor shower, the maximum activity of which falls in mid-December. Perhaps it is a degenerate comet that has exhausted its entire supply of volatile compounds, or they were buried under a thick layer of dust.

The asteroid is a small body measuring 5.1 km. Since Phaethon is assumed to be of cometary origin, it is classified as a spectral class B asteroid, with a very dark surface composed predominantly of anhydrous silicates and hydrated clay minerals. The same mixed asteroid-comet features have been found in another object, designated 133P/Elst-Pizarro.

In the 21st century, several very close encounters of this asteroid with the Earth are expected at once: one has already happened on December 10, 2007, when the asteroid flew past our planet at a distance of 18.1 million km, the closest one happened in 2017, the next encounters will occur in 2050, 2060 and the closest in 2093, December 14, when the expected distance between the Earth and Phaeton will be only about 3 million km.

(2212) Hephaestus(lat. Hephaistos) is a near-Earth asteroid from the Apollo group, characterized by an extremely elongated orbit and, therefore, has become quite widely known. It was discovered on September 27, 1978 by Soviet astronomer Lyudmila Chernykh at the Crimean Astrophysical Observatory and named after the ancient Greek god of fire and blacksmithing Hephaestus.

The very large eccentricity of the orbit causes significant fluctuations in the distance of Hephaestus to the Sun, due to which this asteroid not only crosses the orbits of all four terrestrial planets from Mercury to Mars at once, but also, crossing the entire asteroid belt, comes close to the orbit of Jupiter.

Eccentricity - 0.837; Perihelion - 52.591 million km; Aphelion - 594.265 million km; Inclination - 11.58 °; Diameter - 5.7 km.

(163693) Atira(lat. Atira) - a small rapidly rotating near-Earth asteroid that leads the Atira group; the first discovered asteroid whose orbit is completely inside the orbit of the Earth. It was discovered on February 11, 2003 as part of the LINEAR asteroid search project at the Socorro Observatory and is named after Atira, the mother earth goddess and evening star in Pawnee mythology.

According to the established tradition, a new group of near-Earth asteroids gets its name in honor of its first discovered representative. Therefore, the choice of a name for this asteroid was approached especially seriously. Since the names of the asteroids of the other three groups of near-Earth asteroids (Atons, Amurs and Apollos) began with the letter "A", it was decided that in this case the name of this asteroid began with the same letter. Since the observatory where the asteroid was discovered is located in the southwestern United States, it was decided to use the mythology of the Indians who lived in this area to choose the name. Thus, now the asteroids included in this small but important group of near-Earth asteroids are called the Atira group asteroids.

Due to the elongated orbit (eccentricity 0.322), the asteroid is sometimes closer to the Sun than Venus, and comes quite close to the orbit of Mercury, and it takes just over 233 Earth days for the entire orbit. With a diameter of 4.8 km, the asteroid Atira is the largest representative of all 17 known bodies of this group to date. Perihelion - 75.147 million km. Aphelion - 146.577 million km. Inclination - 25.61 °; Albedo - 0.10.

(99942) Apophis(lat. Apophis) is a near-Earth asteroid discovered in 2004 at the Kitt Peak Observatory in Arizona. Provisional name 2004 MN4, received its own name on July 19, 2005. This tiny asteroid, despite its size (only about 300 meters), can be called the most "hyped" by numerous mass media due to the panic around its possible collision with the Earth, for this reason it is the most famous in the community of near-Earth asteroids.

The asteroid is named after the ancient Egyptian god Apophis (in ancient Greek pronunciation - Άποφις, Apophis) - a huge serpent, a destroyer who lives in the darkness of the underworld and tries to destroy the Sun (Ra) during his nightly transition. The choice of such a name is not accidental, since according to tradition, small planets are called the names of Greek, Roman and Egyptian gods. Scientists D. Tolen and R. Tucker, who discovered the asteroid, allegedly named it after the negative character from the Stargate SG-1 series Apophis, also taken from ancient Egyptian mythology.

The asteroid belongs to the group of atons, and approaches the Earth's orbit at a point approximately corresponding to April 13th. Eccentricity - 0.19; Perihelion - 111.611 million km; Aphelion - 164.349 million km; Orbital period - 0.886; Inclination - 3.332°; Albedo - 0.23.

According to new data, Apophis will approach the Earth in 2029 at a distance of 38,400 km from the center of the Earth (according to other sources: 36,830 km, 37,540 km, 37,617 km) from it. After the radar observations were made, the possibility of a collision in 2029 was ruled out, however, due to the inaccuracy of the initial data, there was a possibility of a collision of this object with our planet in 2036 and subsequent years. Various researchers have estimated the mathematical probability of collision as 2.2·10−5 and 2.5·10−5. There was also a theoretical possibility of a collision in subsequent years, but it is significantly lower than the probability in 2036.

According to the Turin scale, the danger in 2004 was rated at 4 (Guinness record), however, it remained at level 1 until August 2006, when it was lowered to 0.

In October 2009, positional observations of the asteroid were published, made at the Mauna Kea and Kitt Peak observatories on two-meter telescopes from June 2004 to January 2008. Some time later, taking into account new data, scientists from the Jet Propulsion Laboratory (NASA division) were the recalculation of the trajectory of the movement of the celestial body was carried out, which made it possible to significantly reduce the level of the asteroid hazard of Apophis. If earlier it was assumed that the probability of an object colliding with the Earth is 1:45,000, now this figure has decreased to 1:250,000.

After the asteroid approached the Earth on January 9, 2013 to a distance of 14 million 460 thousand km (which is less than a tenth of the distance from the Sun), it turned out that the volume and mass of Apophis is 75% more than previously thought.

New data on the asteroid Apophis were obtained using the Herschel space observatory. According to previous estimates, the diameter of Apophis was supposedly 270 ± 60 meters. According to updated data, it is 325 ± 15 meters. A 20% increase in diameter gives more than a 70% increase in volume and (assuming homogeneity) mass of a celestial body. Apophis reflects only 23% of the light falling on its surface.

The location of the possible places of the fall of Apophis, if he collided with the Earth in 2036.

NASA's initial estimate for the TNT equivalent of an asteroid impact explosion was 1,480 megatons (Mt), later reduced to 880, and later to 506 Mt, after clarification of the dimensions. For comparison: the energy release during the fall Tunguska meteorite estimated at 10-40 Mt; the explosion of the Krakatoa volcano in 1883 was equivalent to about 200 Mt; the explosion energy of the AN602 thermonuclear aerial bomb (aka Tsar Bomba) at the Dry Nose nuclear test site (73°51′ N 54°30′ E) on October 30, 1961, according to various sources, ranges from 57 to 58.6 megatons of TNT; the energy of the explosion of the nuclear bomb "Kid" over Hiroshima on August 6, 1945, according to various estimates, is from 13 to 18 kilotons.

The effect of the explosion could vary depending on the composition of the asteroid, as well as the location and angle of impact. In any case, the explosion would cause massive destruction over an area of ​​thousands of square kilometers, but would not create long-term global effects like an "asteroid winter".

It should be noted that due to the updated data on the size, which turned out to be somewhat larger, the consequences of the impact could have been more devastating.

According to the proposals of scientists, in order to clarify the trajectory, composition and mass of the asteroid, it is necessary to send an automatic interplanetary station (AMS) to it, which will carry out the necessary research and install a radio beacon on it to accurately measure changes in its coordinates over time, which will allow more accurate calculation of the elements of the orbit, gravitational orbital perturbations from other planets, and thus better predict the probability of a collision with the Earth.

In 2008, the American Planetary Society held an international competition of projects to send a small AMS to Apophis for trajectory measurements of an asteroid, in which 37 institute and other initiative teams from 20 countries of the world took part.

One of the most exotic options suggested that Apophis should be wrapped in a highly reflective film. The pressure of sunlight on the film will change the orbit of the asteroid.

NASA has almost completely ruled out the possibility of a collision of Apophis in 2036 with the Earth. This conclusion was made on the basis of data collected by several observatories during the flyby of Apophis at a distance of 14.46 million kilometers from Earth on January 9, 2013.

Also, scientists previously believed that after a close approach to the Earth in 2029, the orbit of Apophis may change, which will lead to an increased risk of its collision with our planet in 2036 during the next approach. Now this possibility is almost completely eliminated.

In the computer game Rage, the asteroid Apophis crashes into Earth on April 13, 2029, killing 5 billion people within the first day. Before the catastrophe, the best politicians, scientists and military leaders were placed in specially built cryo-arks. The arks should come to the surface with the stored human cargo when the damage inflicted by Apophis wears off.

(3552) Don Quixote(Spanish: Don Quijote) is a near-Earth asteroid from the Amur group (IV), belonging to a rather rare spectral class D. Due to its highly elongated orbit, due to its significant eccentricity, the asteroid immediately crosses both the orbit of Mars and the orbit of Jupiter, while , in its perihelion approaching the Earth's orbit quite close (up to a distance of 0.193 AU), which determines its belonging to the asteroids of the Amur group and allows it to be attributed to "objects approaching the Earth."

All this suggests that the asteroid (3552) Don Quixote is actually a degenerate comet that has already exhausted its reserves of volatile substances and has turned into an ordinary block of stone. This asteroid has one of the longest periods of revolution around the Sun from the near-Earth group - 8.678 years andis one of the darkest known asteroids, with an albedo of about3 %. .

Eccentricity - 0.71; Perihelion - 181.022 million km; Aphelion - 1.08248 billion km; Inclination - 30.96; Diameter - 19.0 km.

(3691) Trouble(lat. Maera) is a small near-Earth asteroid from the Amor (II) group, which was discovered on March 29, 1982 by the Chilean astronomer LE González at the Cerro El Roble observatory and named after the Benedictine monk who wrote the first works on the history of England, known as Bede the Venerable .

The asteroid is remarkable in that, with its size of just over 4 kilometers, it has an extremely slow rotation period - more than 9 days. Unstoppable Trouble....

Eccentricity - 0.28; Perihelion - 189.982 million km; Aphelion - 340.886 million km: Orbital period - 2.363 years; Inclination - 20.35°

Other extreme, asteroid 2008 HJ - an unnamed near-Earth asteroid from the Apollo group.

The history of the discovery of the asteroid 2008 HJ is interesting. It was discovered in April 2008 by amateur astronomer Richard Miles from Dorset (UK). He made the discovery without leaving his home, thanks to the fact that he had remote access via the Internet to the Australian, fully automated Folkes telescope. The English educational project, in which R. Miles observed the starry sky, provides free of charge to schoolchildren, students and amateur astronomers from the UK the opportunity to work on two large telescopes located in Australia and Hawaii.

From observations of periodic changes in the brightness of an asteroid associated with its rotation, an English amateur found that 2008 HJ makes one revolution around its axis in less than a minute (according to his data, in 42.7 seconds, which is very close to the corrected - 42.67 seconds) . Before the rotation speed of asteroid 2008 HJ was determined, asteroid 2000 DO8 with a rotation period of 78 seconds was considered the record holder. It is possible that other record holders of this kind will be discovered.

The dimensions of the asteroid are quite modest - only 12 by 24 meters. Less tennis court. But the mass of 2008 HJ is about 5,000 tons. Despite the fact that 2008 HJ is included in the category of "near-Earth" asteroids, it did not approach our planet closer than a million kilometers and does not pose a danger. The asteroid was closest to Earth in April, when it swept past at a speed of 162,000 km/h.Circulation period - 2 years; Inclination - 0.92.

Not quite thematic article for me, but it seemed interesting to me to talk about the asteroid danger. In principle, this is a hackneyed topic, but in last years gradually acquires a different content, so I think it will be interesting.

Impact

Simulation of the atmospheric explosion of the Tunguska meteorite. Modern estimates give the power of this impact at 5..15 megatons.

An impact is the impact of an asteroid (in principle of any size) on the Earth, followed by the release of its kinetic energy in the atmosphere or on the surface. The smaller the energy impact, the more often it occurs. The impact energy is in a good way determine whether a space body is dangerous for the earth or not. The first such threshold is somewhere around 100 kilotons of TNT equivalent of energy release, when an incoming asteroid (which, upon entering the atmosphere, begins to be called a meteorite) ceases to be limited to hitting YouTube, but begins to bring trouble. A good example of such a threshold event is Chelyabinsk meteorite 2014 - a small body with characteristic dimensions of 15 ... 20 meters and a mass of ~ 10 thousand tons with its shock wave caused damage to a billion rubles and injured ~ 300 people.

A selection of videos of the fall of the Chelyabinsk meteorite.

However, the Chelyabinsk meteorite aimed very well, and in general did not particularly disturb the life of even Chelyabinsk, not to mention the whole Earth. The probability of accidentally hitting a densely populated area in a collision with our planet is about a few percent, so the real threshold of dangerous objects begins with a power 1000 times greater - about hundreds of megatons, the characteristic impact energy for bodies caliber 140-170 meters.

Unlike nuclear weapons, meteorites' energy release is more spread out in space and time, and therefore slightly less lethal. In the photo - the explosion of the Ivy Mike nuclear installation, 10 megatons.

Such a meteor has a radius of destruction of a hundred kilometers, and a successful landing can end many millions of lives. Of course, there are stones in space and a larger size - a 500-meter asteroid will arrange a regional catastrophe, affecting the area thousands of kilometers from the place of its fall, a 1.5-kilometer asteroid can erase life from a quarter of the planet's surface, and a 10-kilometer asteroid will arrange a new mass extinction and will definitely destroy civilization.

Now that we've calibrated Armageddon's level against size, let's get to the science.

Near Earth asteroids

Obviously, only the asteroid whose orbit will intersect the Earth's trajectory in the future can become an impactor. The problem is that you first need to see such an asteroid, then measure its trajectory with sufficient accuracy and model it into the future. Until the 80s, the number of known asteroids that crossed the Earth's orbit was in the tens, and none of them posed a danger (did not pass closer than 7.5 million kilometers from the Earth's orbit when modeling the dynamics, say, 1000 years ahead). Therefore, the study of the asteroid hazard was mainly focused on a probabilistic calculation - how many bodies larger than 140 meters can be in orbits crossing the Earth? How often do impacts occur? The danger was estimated probabilistically “in the next decade to get an impact with a capacity of more than 100 megatons is 10^-5”, but the probability does not mean that we will not get global catastrophe already tomorrow.

Calculation of the probable frequency of impacts depending on the energy. On the vertical axis, the frequency of "cases per year", on the horizontal - the impact power in kilotons. Horizontal stripes - tolerances on the value. Red marks - observations of real impacts with an error.

However, the qualitative and quantitative growth leads to a rapid increase in the number of detected near-Earth objects. The appearance in the 90s of CCD matrices on telescopes (which increased their sensitivity by 1-1.5 orders of magnitude) and at the same time automatic algorithms for processing images of the night sky led to an increase in the rate of detection of asteroids (including near-Earth ones) by two orders of magnitude at the turn of the century.

Good animation of asteroid detection and movement from 1982 to 2012. Near-Earth asteroids are shown in red.

In 1998-1999, the LINEAR project comes into operation - two robotic telescopes with an aperture of only 1 meter, equipped with only a 5-megapixel (later you will understand where “everything”) matrix comes from, with the task of detecting as many asteroids and comets as possible, including .h. near-Earth. This was not the first project of this kind (a couple of years earlier there was still quite successful NEAT), but the first one specially designed for this task. The telescope was distinguished by the following features, which would then become standard:

• A special astronomical CCD array with pixel backlighting, which increased its quantum efficiency (the number of recorded incident photons) to almost 100%, against 30% for standard non-astronomical ones.
• A wide-angle telescope that allows you to shoot very large surface sky.
• A private cadence - a telescope photographed the same part of the sky 5 times during the night with a gap of 28 minutes and repeated this procedure in two weeks. The frame exposure in this case was only 10 seconds, after which the telescope moved to the next field.
• Special algorithms that subtracted stars from the frame from the catalog (this was an innovation) and searched for moving groups of pixels with certain angular velocities.

The original image (adding 5 exposures with a cadence of 28 minutes) of the LINEAR telescope and after processing by the algorithm. The red circle is a near-Earth asteroid, the yellow circles are main belt asteroids.

The LINEAR telescope itself, located in White Sands, New Mexico.

LINEAR will become the star of the first magnitude of the asteroid search, discovering 230,000 asteroids over the next 12 years, including 2,300 crossing the Earth's orbit. Thanks to another MPC (Minor Planet Center) project, information on found asteroid candidates is distributed to various observatories for additional measurements of orbits. In the 2000s, a similar automated Catalina sky survey (which will be more focused on searching for near-Earth objects, and will find them in the hundreds a year) comes into operation.

The number of near-Earth asteroids discovered by different projects by years

Gradually, estimates of the probability of Armageddon generally begin to yield to estimates of the probability of death from a particular asteroid. Among first hundreds, and then thousands of near-Earth asteroids, approximately 10% are distinguished whose orbits are closer than 0.05 astronomical units from the Earth's orbit (approximately 7.5 million km), while the size of the asteroid should exceed the size of 100-150 meters (the absolute stellar magnitude of the body solar system H>22).

In late 2004, NASA told the world that the asteroid Apophis 99942, discovered at the beginning of the year, had a 1 in 233 chance of hitting Earth in 2029. The asteroid, according to modern measurements, has a diameter of about 330 meters and an estimated mass of 40 million tons, which gives about 800 megatons of explosion energy.

Radar image of the asteroid Apophis. The measurement of the trajectory by radar at the Arecibo observatory made it possible to refine the orbit and exclude the possibility of a collision with the Earth.

Probability

However, on the example of Apophis, the very probability of a particular body to become an impactor surfaced. Knowing the asteroid's orbit with finite accuracy and integrating its trajectory again with finite accuracy, by the time of a potential collision, only an ellipse can be estimated, which will contain, say, 95% of possible trajectories. As the parameters of the orbit of Apophis were refined, the ellipse decreased until the planet Earth finally fell out of it, and now it is known that on April 13, 2029, the asteroid will pass at a distance of at least 31,200 km from the Earth's surface (but again, this is the nearest edge of the error ellipse).

An illustration of how the tube of possible orbits of the asteroid Apophis was shrinking at the moment of a possible collision as the orbit parameters were refined. As a result, the Earth was not affected.

Another interesting illustration on Apophis is the calculation of possible collision points (taking into account uncertainty) for a collision in 2036. It can be seen, by the way, that the trajectory passed near the site of the fall of the Tunguska meteorite.

By the way, for a quick assessment of the relative danger of near-Earth asteroids, two scales were developed - the simple Turin and the more complex Palermo. Turin simply multiplies the collision probability and the size of the estimated body, assigning it a value from 0 to 10 (for example, Apophis at the peak of the collision probability had 4 points), and Palermo calculates the logarithm of the ratio of the probability of impact of a particular body with the background probability of impact of such energy from today to the moment of possible collisions.

At the same time, positive values ​​on the Palermo scale mean that one single body becomes a more significant potential source of disaster than all the others - discovered and undiscovered combined. Another important point of the Palermo scale is the applied convolution of the impact probability and its energy, which gives a rather counterintuitive curve of the degree of risk from the size of the asteroid - yes, 100-meter stones are not capable of causing significant damage, but there are many of them and they fall out relatively often, in general, carrying more potential victims than the 1.5 kilometer "killers of civilizations".

However, let us return to the history of the discovery of near-Earth asteroids and potentially dangerous objects among them. In 2010, the first telescope of the Pan-STARRS system was put into operation, with an ultra-wide-field telescope with an aperture of 1.8 meters, equipped with a 1400 megapixel matrix!

A photograph of the Andromeda galaxy from the Pan-STARRS 1 telescope, which makes it possible to estimate its wide angle. For comparison, inscribed in the field full moon and colored squares - the "usual" field of view of large astronomical telescopes.

Unlike LINEAR, it takes 30 second shots with a depth of view of 22 stars. magnitude (i.e. could detect an asteroid 100-150 meters in size at a distance of 1 astronomical unit, against the kilometer limit at that distance for LINEAR), and a high-performance server (1480 cores and 2.5 petabytes of hard drives) turns 10 terabyte to the list of transient phenomena. Here it should be noted that the main purpose of Pan-STARRS is not the search for near-Earth objects, but stellar and galactic astronomy - the search for changes in the sky, such as distant supernovae, or catastrophic events in close binary systems. However, hundreds of new near-Earth asteroids were discovered in this delusional telescope during the year.

Server Pan-STARRS. Generally speaking, the photo is already in 2012, today the project has expanded quite a lot, a second telescope has been added, two more are under construction.

Another mission worth mentioning is NASA's WISE Space Telescope and its NEOWISE extension. This device took pictures in the far infrared, detecting asteroids by their IR glow. Generally speaking, it was originally aimed at searching for asteroids beyond the orbit of Neptune - Kuiper belt objects, scattered disk and brown dwarfs, but in the extension mission, after the telescope ran out of coolant and its temperature became too high for the original task, this The telescope has found about 200 near-Earth bodies.

As a result, over the past 30 years, the number of known near-Earth asteroids has increased from ~50 to 15000. Of these, 1763 are currently listed as potentially hazardous objects, none of which have ratings greater than 0 on the Turin and Palermo scales.

Lots of asteroids

Is it a lot or a little? After the NEOWISE mission, NASA re-estimated the model number of asteroids as follows:

Here in the picture, the known near-Earth asteroids (not only dangerous objects) are shown in shaded, the outlines are an assessment of existing ones, but not yet found. situation in 2012.

Now estimates of the proportion of discovered asteroids are made through the model synthesis of the population and the calculation of the visibility of the bodies of this population from the Earth. This approach allows a good estimate of the proportion of detected bodies, not only through the extrapolation of the "size-number of bodies" function, but also taking into account visibility.

The red and black curves are model estimates of the number of bodies of different sizes in near-Earth orbits. The blue and green dotted lines are the number detected.

The black curve from the previous picture in tabular form.

Here, in the table, the sizes of asteroids are given in units of H - absolute stellar magnitudes for objects in the solar system. A rough conversion to size is made using this formula, and from it we can conclude that we know more than 90% of near-Earth objects larger than 500 meters and about half the size of Apophis. For bodies from 100 to 150 meters, only about 35% is known.

However, we can recall that a miserable 30 years ago, about 0.1% of dangerous objects were known, so the progress is impressive.

Another estimate of the proportion of discovered asteroids, depending on the size. For bodies 100 meters in size, a few percent of the total has been detected today.

However, this is not the end of the story. Today, the LSST telescope, another monster survey telescope, is being built in Chile, which will be armed with 8 meter optics and a 3.2 gigapixel camera. In a few years, starting in 2020, having taken about 50 petabytes (generally the project's motto is "turning the skies into a database") of LSST images, it should detect ~ 100,000 near-Earth asteroids, determining the orbits of almost 100% of bodies of dangerous sizes. By the way, in addition to asteroids, the telescope should produce several billion more objects and events, and the same database should eventually amount to 30 trillion rows, which is a certain difficulty for modern DBMS.

To accomplish its task, the LSST has a very unusual optical design, where the third mirror is placed in the center of the first.

Cooled down to -110 C 3.2 gigapixel camera with a pupil of 63 cm is the working tool of LSST.

Is humanity saved? Not really. There is a class of stones that are in orbits internal to the Earth in a 1:1 resonance, which are very difficult to see from the Earth, there are long-period comets - usually relatively large bodies with very high velocities relative to the Earth (i.e. potentially very powerful impactors), which we can notice today no more than 2-3 years before the collision. However, in fact, for the first time in the last three centuries, since the idea of ​​the collision of the Earth with a celestial body was born, in a few years we will have a database of trajectories of the overwhelming number of dangerous bodies carrying the Earth.

In the next part, I will describe the point of view of science on the methods of influencing dangerous asteroids.

Scales

There are several scales for assessing the risk of POO.

Turin scale

• Asteroids (0 points) - consequences of the collision: they have no chance to meet the Earth.
• Asteroids (10 points) - the consequences of the collision: the number of species inhabiting our planet should be reduced by orders of magnitude.

Judging by the geological data (several hundred impact craters have been explored), collisions with large celestial bodies have happened more than once in the history of our planet. The fall of one large meteorite, some scientists explain the mass extinction of living organisms (about 250 million years ago). Another meteorite, according to the hypothesis of U. Alvarez, led to the extinction of dinosaurs.

Sources

Closest to Earth was a small asteroid 2004 FU 162 (diameter about 6 meters) - about 6500 km from Earth (March 2004).

Discovery history

Historically, Eros (, Amur group) was the first of the asteroids with an orbit close to the Earth. The largest asteroid in the Amur group is Ganymede (which should not be confused with the satellite of the same name of Jupiter), its diameter is approximately 32 km (Eros has about 17 km).

• Asteroid 2008 TC 3 - discovered 20 hours before it burned up in the atmosphere over Sudan on October 7, 2008.
• Asteroid 2009 DD 45 - discovered on February 28, 2009 (three days before it approached the Earth at a minimum distance) by astronomer Robert McNaught, who studied photographs taken using the Schmidt telescope from the Siding Springs Observatory in Australia. The asteroid made its closest approach to the Earth on March 2, 2009 (16:44 Moscow time, according to representatives of the Planetary Society - 13:44 GMT). It could be seen with the naked eye in the skies over the South Pacific. Dimensions - 20-50 (27-40) meters. The distance to the Earth is 66 (72) thousand km. The spread of numbers is due to the fact that the diameter of asteroids is calculated on the basis of their albedo - reflectivity. Since astronomers don't know exactly how much light the surface of 2009 DD45 reflects, they start from averages. Movement speed - (at the moment of being at a minimum distance from the Earth - 20 km / s. In a collision, the explosion energy would be equal to 1 megaton (one high-power nuclear bomb) in TNT equivalent. For comparison: by the impact of the Tunguska meteorite (exploded in the atmosphere over Siberia 30 June 1908) 80 million trees were felled over an area of ​​about 2,000 square kilometers, which corresponds to an explosion of 3-4 megatons of TNT.

Problematic detection

Financial

Scientists note that even small objects pose a threat to the Earth, since their explosions near the planet as a result of heating can lead to significant destruction. However, NASA currently tracks mainly the largest space objects, which are more than a kilometer in diameter (as of 2007, 769 known asteroids and comets, whose diameter does not exceed 140 meters, are not observed so closely).

Technical

Current state

In total, about 6,100 objects have been registered that pass at a distance of up to 1.3 astronomical units from the Earth.

As of April 2009, no PEOs have been observed in the Solar System (a list of just over a thousand positions, where 90% are asteroids, 10% are comets, the distance from them to the Earth is less than 0.05 astronomical units), which would be able to overcome the milestone of zero points.

The danger that asteroids pose to the planet is not regarded as serious. According to modern estimates, collisions with such bodies (according to the most pessimistic forecasts) are unlikely to occur more often than once every hundred thousand years. If a celestial body large enough to cause serious damage is directed towards the Earth, astronomers will be able to detect it.

see also

Notes

Links

• Zheleznov N. B. Asteroid-comet hazard: the current state of the problem.
• Finkelstein A., corresponding member RAN. Asteroids threaten the Earth. Science and Life, No. 10, 2007, pp. 70-73.
• Earth Impact Crater Database.
• Near-Earth Asteroid Database.

Wikimedia Foundation. 2010 .

(Astronomy@Science_Newworld).

The unexpected low number of asteroids in near-Earth space is due to the fact that the sun constantly "grinds" asteroids approaching it, turning them into a set of small particles that subsequently form bright meteor showers in the earth's night sky, according to an article published in the journal Nature.

"The discovery that asteroids break up when they get too close to the sun was so amazing to us that we spent a very long time checking and rechecking our calculations," said Robert Jedicke from the University of Hawaii at Honolulu (USA). .

Jedicke and colleagues came to this conclusion by comparing maps of asteroids compiled from data from a catalog of near-Earth objects collected as part of the Catalina Sky Survey project with those predicted by models of the solar system.

As this comparison showed, the number of near-Earth and near-Sun asteroids known to us is extremely small - in fact, according to computer models the inner part of the solar system, there should be about 10 times more.

In an attempt to explain this mysterious disappearance of asteroids, scientists tracked the movement of several near-Earth celestial bodies in orbits in this model, trying to uncover orbital mechanisms that would "catapult" extra minor planets from the vicinity of the orbits of Mercury, Earth and Venus, or otherwise clean this part of the solar system from the "heavenly stones".

These calculations led to unexpected results - it turned out that the main "Cleaner" of the inner regions of the solar system is the sun itself, periodically destroying asteroids that fly closer to it at a distance closer than 10-15 luminary radii.

Prior to this, scientists believed that the sun was not capable of heating asteroids approaching it to temperatures high enough to cause them to evaporate or otherwise form destruction. As Yedike and his colleagues found out, the destruction of asteroids proceeds in a different way, the essence of which has yet to be clarified.

According to the astronomers themselves, this process can occur as follows: when an asteroid approaches the sun, its surface can begin to crack and break into small segments, dust particles from which are “Knocked out” and carried away by the solar wind and photons of light.

Another option for the disintegration of these asteroids is that the evaporation of gases inside them and the pressure of light can cause them to spin up to very high speeds, as a result of which the celestial body simply disintegrates into small fragments under the action of centrifugal forces. This is supported by the existence of various meteor showers around the sun, which periodically illuminate the night sky of the earth on certain days and weeks of the year.

On the other hand, as data from the Wise telescope show, the decay process of asteroids with different surface brightness will differ, both in the mechanism and in the distance at which it occurs - for example, darker celestial bodies should fall apart earlier than the lighter ones, which speaks in favor of the first scenario. In any case, both variants of decay show that the life of a near-Earth asteroid is short-lived - on average, it should live no more than 250 years.

Scientists believe that we will be able to see such a decay very soon - the asteroid 2006 Hy51 today flies very close to the sun, approaching at a distance of 17 luminary radii. Another victim of the sun may be a large five-kilometer near-Earth asteroid phaeton, approaching only 20 million kilometers to the sun, on the surface of which planetary scientists recently found traces of destruction. Jedicke and his colleagues plan to conduct observations of these objects in the near future, checking their calculations.