Astronomers all over the world do not stop their observations of the flight of Apophis, an asteroid, which after a while will approach a very small distance to the Earth.
Several years ago, the news of this rapprochement was very disturbed by the public, but nowadays people hardly remember about it. But experts remember well.
For the first time, a dangerous asteroid was discovered by American astronomers from the Keith Peak National Observatory, which is located in Arizona. Its name speaks for itself, because the asteroid was called Apophis, and this is how the ancient Greek god of destruction and darkness was called. This god was depicted as a huge destroyer snake that lived in the underworld and from there tried to destroy the Sun, while it makes a night transition. It should be noted that the choice of such a name for the asteroid is quite justified and traditional, because from the very beginning all celestial bodies were called the names of the ancient gods, and only then they only began to call the names of real historical characters.
Scientists have found that the asteroid crosses the near-earth orbit every seven years, and with each new "visit" it increasingly reduces the distance to the planet. According to experts, Apophis will approach a distance of just over 35 thousand kilometers in April 2029, and it could collide with the Earth in 2036.
A little earlier, in early 2011, at one of the scientific conferences held in Moscow, an employee of St. Petersburg State University Leonid Sokolov named even the most likely date of the collision, namely April 13, 2036. At the same time, scientists have not yet been able to determine exactly where the collision point will be. Still, there are certain assumptions put forward by Boris Shustov, Director of the Institute of Astronomy of the Russian Academy of Sciences. According to him, the asteroid may collide with the Earth in the zone from the Urals, along the border of Russia, Mongolia and Kazakhstan, through the waters of the Pacific Ocean, Central American territories, Atlantic waters and to the African coast. In addition, it is not so easy to accurately predict the orbit of an asteroid. The fact is that there is the Yarkovsky effect, the essence of which is the existence of a small but effective force. It manifests itself in the fact that on one side the asteroid emits more heat than on the other. When an asteroid turns away from the Sun, it begins to radiate heat accumulated in the upper layers. Thus, a small reactive force appears, which acts in the direction opposite to the heat flow. Scientists do not even suggest how exactly this effect can affect the trajectory of Apophis, about which practically nothing is known - neither the speed of rotation, nor the direction of the axis along which it rotates. But it is these parameters that are necessary to determine the Yarkovsky effect.
But Russian scientists are in a hurry to reassure the public, stating that the probability of a strike is very small, it is about 1 in 100 thousand. The reason for such confidence of scientists in the relative safety of Apophis for the Earth lies in the fact that they were able to more accurately determine its orbit. At the same time, scientists do not exclude the fact that even if there is no collision in 2036, this may well happen in subsequent years. At the same time, Russian astronomers rely on the results of NASA research, according to which about 11 collisions with the planet are expected this century, and 4 of these collisions may occur before 2050.
If, nevertheless, a collision of Apophis and the Earth occurs, humanity is in mortal danger. Despite the fact that the asteroid itself is small (its diameter is about 270-320 meters), the impact of an object with a mass of several tens of millions of tons on the surface of the planet at a tremendous speed (about 50 thousand kilometers per hour) can cause an explosion, the power of which will be equal to 506 megatons. Thus, in the case of "contact", the energy of the explosion can be compared with the detonation of all nuclear weapons that exist on the planet. The damaging factors will be similar to the consequences of a nuclear weapon explosion, except that there will be no radiation.
At the same time, Russian scientists argue that according to the studies carried out, the probability of death from a collision with an asteroid is approximately 1 in 200 thousand.
It should be noted that today more than 830 potentially dangerous asteroids are under the close scrutiny of Russian and American scientists, and among them there are also larger ones than Apophis. Therefore, a collision with any of them can completely destroy the planet. According to Boris Shustov, the most dangerous is the recently discovered asteroid, which the planet may collide with in eight hundred years. The only "good news" is that celestial objects of this size appear within the Earth once every tens of millions of years.
Currently, according to scientists, there are about 7 thousand celestial objects that are approaching the planet Earth, of which about a seventh are potentially dangerous. At the same time, American astronomers argue that after 2029, humanity will have enough time to slightly move Apophis out of its orbit so that it does not fall into the so-called "gravitational well", that is, the field that is on the approaches to planet and which can direct an asteroid directly at it. Therefore, several methods have been proposed to shift a celestial object from its shaved, in particular: a powerful frontal impact, changing the orbit using a rocket engine used as a "tractor". In addition, you can try to change the trajectory of the asteroid by detonating a nuclear charge on its surface.
According to the leading researcher of the Institute of Astronomy of the Russian Academy of Sciences, Doctor of Physical and Mathematical Sciences, Alexander Bagrov, today mankind has created more than 40 different means to deal with various celestial objects that pose a threat to the planet. The most discussed are two options - the Russian one, which assumes the placement of a radio beacon on an asteroid, and the American one, which assumes a nuclear attack by Apophis in the event of its critical approach to the Earth.
In addition, there are other equally interesting developments. So, in particular, the European Union plans to allocate about 4 million euros for a three-year project called NEO-Shield. Scientists from six states will participate in this project, who must develop various ways to protect against potentially dangerous celestial objects. Another certain amount of funds (about 1.8 million euros) will be allocated by European research institutes and enterprises related to the aerospace industry. By the way, it was these structures that actively supported the initiative of the European Union, because earlier it did not allocate money for such research. The funding coincided with a cut in the US government budget for the space industry. Thus, from the point of view of theoretical developments, Europeans can feel proud that they have been given the honorable mission of saving the planet. But at the same time, this project does not imply the practical implementation of the developed strategies.
According to representatives of the European aerospace company Astrium, the construction of a real shield against asteroids will require significant investments (about 300 million euros), and the Europeans do not have such an amount. By the way, precisely because of the lack of money, the Don Quixote project was not brought to its logical conclusion, the essence of which was to send a ram satellite to Hidalgo (another dangerous asteroid) in order to change the trajectory of the latter.
Russian astronomers are also not lagging behind, but their research to detect potentially dangerous celestial objects is carried out only within the framework of scientific research work of the scientific research institute. So, in one of the Russian research institutes, the Makeyev rocket center, two spacecraft are currently being developed to combat asteroids. One of them - "Kaissa" - is designed to perform reconnaissance functions, in particular, to assess the chemical composition, structure, trajectory of asteroids. The other is the Kapkan, a striking apparatus carrying several nuclear warheads. We will remind, earlier from the scientists of the center there were proposals to destroy all potentially dangerous objects with the help of nuclear weapons. At the same time, the delivery of warheads should be carried out using the Soyuz-2 and Rus-M launch vehicles.
But still, at present, America holds the first positions in the study of potentially dangerous celestial bodies. Several of the largest centers are located on the territory of the United States, detecting minor planets and space threats. Thus, they receive 99 percent of all information on this issue.
At the same time, American scientists are trying to block access to other states to the data of their research. So, for example, in 2000, they banned Russian scientists from using the results of their observations of the geostationary orbit, and after 9 years - and data on the observation of the entry of fireballs into the earth's atmosphere. In such conditions, Russia simply has to create its own monitoring program for potentially dangerous objects and strive to cooperate with other states. In addition, Roscosmos fears that in connection with the alleged collision of the Earth and Apophis in the world, a new arms race may begin, the end result of which will be the creation of the latest means of armed confrontation not only on the planet, but also in near-earth orbit.
If we talk about American developments in this area, then we cannot ignore the project, which is unique in its essence - the Hypervelocity Asteroid Intercept Vehicle (HAIV). Its essence lies in the creation of a nuclear asteroid interceptor. By and large, we can say that this is a program developed by NASA, aimed at creating technologies to protect the planet from the possible consequences of an asteroid impact. HAIV itself is a spacecraft that, using kinetic energy, can penetrate an asteroid, and then a nuclear bomb must go off. Thus, either the complete destruction of the celestial object will occur, or it will be possible to move it off the trajectory. At the same time, the debris will not be dangerous to the Earth. This technology is expected to become the most effective in the fight against asteroids - less than ten years before the collision, the device will be able to respond to a threat.
It will carry out a direct intercept of a celestial body following the example of the EKV interceptor of the US missile defense system. Homing technologies using optical systems and guidance in the first sections of the trajectory have been sufficiently developed, but there are certain problems. So, for example, if we take into account that the speed of collision of the device with an asteroid will be about 10-30 kilometers per second, then the device will not have enough kinetic energy to destroy the asteroid. The fact is that modern technologies have not yet reached the level of development at which a nuclear device could be detonated at high speed, since upon impact, the components of this device will be completely destroyed, and there will simply be no explosion.
That is why the developers of the project have designed a special nose section, which will be separated and which should punch, roughly speaking, a hole in the asteroid so that the interceptor with a nuclear bomb can safely enter the interior of the asteroid. If the calculations of NASA specialists are justified, then the nuclear explosion will have a yield of about 6 megatons.
The project of the company from the United States SEI is also of some interest. Its essence is to launch small robots on an asteroid. They must burrow into the surface of the object, throw the rock into space and thus change the trajectory of its movement.
Another American non-profit structure, the B612 Foundation, which includes scientists and former NASA astronauts, proposes to launch its infrared telescope into space in 2017-2018, which will search and track potentially dangerous asteroids. The name of the organization is borrowed from literature, from the story of A. de Saint-Exupery "The Little Prince". All of its members are convinced that American astronomers do not pay enough attention to small asteroids, preferring to study large objects with a diameter of at least one kilometer. Their telescope, on the other hand, is designed to track small celestial objects. The Sentinel telescope will be in near-earth orbit for about 5.5 years at a distance of 50-270 million kilometers from the planet. Thus, it is assumed that for the entire period of its stay in space, the telescope should find about 90 percent of all small asteroids with a diameter of more than 150 meters. Several hundred million dollars are needed to implement the project.
There are also international developments. So, quite recently, a technology for "painting" celestial objects was developed, which is designed to protect the planet from a potential threat. Scientists from the University of Texas, together with the Ames Research Center (NASA) and the Science Center of the ruler of Saudi Arabia, Abdel Aziz, have contributed to the development of anti-asteroid technologies. They proposed changing the trajectories of asteroids without using nuclear weapons. The essence of their technology is to influence the motion of a celestial object by changing its reflectivity. To do this, it is necessary to apply paint (either light or dark) to the surface of the asteroid using a special unmanned spacecraft. At the same time, the Yarkovsky effect will begin to operate actively. Since the reactive force that arises under its influence is very small, it can be significantly increased with the help of contrasting paints. Scientists want to try their method on Apophis. At the very beginning of the mission, called the Apophis Mitigation Technology Mission (AMTM), it is planned to send a small reconnaissance officer to determine the parameters of the asteroid. Then a spacecraft equipped with an electrostatic painting unit should go to him, which will cover some areas of Apophis with paint. According to scientists, this will make it possible to change the asteroid's albedo and deflect its trajectory by about three degrees.
