There are no grounds for fears yet, but they are available for contemplation.
Messages from the Chelyabinsk region sometimes take on an apocalyptic tone: “hundreds of wounded”, “eight districts of the Chelyabinsk region have suffered”, “significant damage has been caused”, “Emergencies Ministry employees are working on the spot.” The imagination draws smoking ruins, which were once city buildings, trying to get out from under the rubble of people in torn clothes with traces of blood on their faces, dismantling the debris of rescuers in helmets and uniforms, and above all this nightmare a low sky, the gloom of which is complemented by crawling over it soot tongues. In general, everything is as it should be in a Hollywood movie about the end of the world..
Reality, as is often the case, is much simpler and more prosaic. A large meteorite (fireball) or a small asteroid fell. In some places in Chelyabinsk, glass flew out, which injured people. How much is yet to be clarified, although the Russian press has already named more than 1000 people. So many asked for help with minor cuts and bruises.
Of the buildings, the zinc plant suffered the most, with the roof blown off and the wall damaged. However, this did not affect the work of the enterprise, and it continued to function as usual. Plus, mobile communication was lost for some time. That, it seems, is all. True, according to preliminary estimates, the damage from the fall of the meteorite amounted to a billion rubles..
What has fallen is lost
Alas, this observation often refers to the “guests” from outer space visiting the Earth. The largest “visit” recorded in modern history – the fall of the Tunguska meteorite in the taiga in 1908 left nothing for research except thousands of square kilometers of felled and burnt trees.
With the Sikhote-Alin meteorite, which fell in 1947 on the territory of the Primorsky Territory, the situation is a little “better”. Seekers still find iron fragments at the site of his fall (the area of the fall is guarded by them, like a gold mine, because these fragments are bought by lovers of space souvenirs for very big money).
As for the Chelyabinsk meteorite, there have already been reports in the Russian media that its fragments have allegedly been found on the territory of the Chelyabinsk region. This information has not yet been confirmed, but there are chances to find something. After all, the fall was recorded by many surveillance cameras. Based on this data, it will be possible to establish the trajectory of the car’s flight and determine with great accuracy the place where it fell..
What people manage to find on Earth depends not only on the size of the meteorite (it is clear that the larger it is, the less chance it has to completely burn up in the atmosphere). Meteorites are stone, iron and iron-stone. There is also a kind of “snowballs” – the remnants of a comet.
They represent a frozen mass of ice, stones, iron, and possibly stones and iron at the same time. Since such a meteorite consists largely of ice, despite its large size and mass, it is much more likely to collapse in the upper atmosphere than its much smaller counterparts in weight and volume, consisting of iron and stones..
If just such a “snowball” exploded over Chelyabinsk, then there will not be so many chances of finding anything from it. If it is stone, iron, or iron-stone, then the probability of finding its fragments on the ground will be higher. It is the lack of clarity of what the Chelyabinsk meteorite was “made of” and does not allow us to estimate its mass and size. It is believed, however, that meteorites, or more correctly, small asteroids up to 30 meters across, as a rule, collapse in dense layers of the atmosphere, before reaching the ground..
And if he does fly?
Just a few hours ago, a 50-meter asteroid 2012DA14 passed by the Earth. At the point of closest approach to our planet, it was separated from it by only 28,000 kilometers, or 8,000 kilometers less than from any of the geostationary satellites. This asteroid was obviously smaller than the Chelyabinsk one, but what would happen if it fell on our planet?
Scientists estimate that 50-meter asteroids fall to Earth no more than once every 750-800 years (good news). But if it falls, it will release at least 3,000,000 tons of trinitrotoluene – TNT, or 188 Hiroshim (bad news) upon contact with the planet. For comparison: the power of the explosion of the Tunguska meteorite is estimated in the range from 3 to 20 million tons of TNT (nevertheless, closer to good news, because humanity has safely survived the “Tunguska” bombardment “).
But if only 50-meter asteroids threatened the Earth.
In the history of the Earth, there were at least 5 mass extinctions of living beings that inhabited it. The most recent, which happened 65.5 million years ago, is associated by most scientists with the fall of a 10-kilometer asteroid near the village of Chikskulub, located on the territory of the Yucatan Peninsula..
The debris of a celestial body, thrown into the sky, mixed with millions of tons of terrestrial rock, soot from the fires that have arisen, enveloped our planet in a dense veil of smoke and dust. This significantly reduced the amount of sunlight and heat hitting the Earth’s surface, resulting in a sharp cold snap that the heat-loving dinosaurs could not bear. And although not all scientists agree with this explanation of the death of giant lizards, one thing is certain – the collision of the Earth with an asteroid can lead to very serious consequences..
In their scale, they will depend on the size of a celestial body: 100 meters in diameter – a large city such as New York, Mexico City, or Beijing can be destroyed. 300 meters is a serious threat to an entire country the size of France, or Italy. 1000 meters or more – destruction can already be on a planetary scale.
Fortunately, asteroids with their dimensions exceeding a kilometer collide with the Earth no more than once every several million years. And if we talk about such giants as Ganymede (40 kilometers across), then the probability of collision with them is estimated as once every 20 million years. However, even 100-meter asteroids, which, according to scientists, fall to Earth no more than once in a thousand years, can cause a lot of troubles on it, as already noted..
However, I would still like to end with “good news”. The likelihood of falling celestial “debris” on the Earth in modern times is noticeably less than millennia, or millions of years ago, because its neighboring planets perform the role of “cleaners”, gradually attracting to themselves “construction waste” left over from the creation of the solar system.
We will defend
Currently, five main ways of dealing with the asteroid-comet hazard are being considered. The first was very figuratively presented in the movie “Armageddon” – to destroy an asteroid with the help of a nuclear device delivered to its surface. True, the result of this explosion will only be that instead of one large asteroid, several smaller debris will rush to the Earth, so the feat of Bruce Willis in real life, alas, would not have saved the Earth. The other four ways are more gentle for the heavenly “fragment” – not to blow it up, but simply to take it away from the trajectory of collision with the Earth..
Among them, the first is to hit an asteroid with a man-made object (this method was tested in 2005, when NASA purposefully rammed comet 9P / Tempel using the Penetrating Impact spacecraft to analyze comet matter). The second is to smash the “barrel” of paint on the asteroid, making one half of it darker than the other. In this case, the “Yarkovsky effect” will work (named after the Russian engineer who discovered it at the beginning of the last century). The dark side will heat up more and, therefore, emit more infrared waves, which, acting as micro-rocket engines, will gradually reduce the asteroid from the trajectory of collision with the Earth..
The third way is to deliver a “tug” in the form of a propulsion system (or a solar “sail”) to the asteroid and fix it on its surface. By the way, the concept of this method has also been tested in practice. In 2001, the American automatic apparatus “Shoemaker” landed on the asteroid Eros, and in 2005 the Japanese probe “Hayabusa” not only sank to the surface of the asteroid Itokawa, but also took samples of its substance, after which it returned safely to Earth in June 2010.
And, finally, the fifth method, a very exotic one, is to put some man-made celestial body into orbit around the asteroid, which, by its gravitational effect, will change the trajectory of its flight. The technical feasibility of this option will be tested during the mission of the NASA spacecraft Dawn (translated from English – “dawn”). In 2011-2012, Dawn orbit around the asteroid West, the first by mass and the second largest known asteroid (the first is Pallas), and then headed towards the dwarf planet Ceres, around which it should begin circling in 2015..
Of all these methods, the most acceptable are those associated with external mechanical impact on the asteroid, that is, either hitting it, thereby knocking it off a dangerous trajectory, or taking it away from it with the help of a “tug”. Moreover, the “tug” has a clear advantage associated with the ability to more accurately and for a long time to issue the desired impulse, as well as correct its direction.
What is really being done?
Meteor Strikes Russia, Over 1,000 Believed Injured
So far, a little. The United States is currently at the forefront of the fight against the asteroid hazard. Moreover, even there we are talking about some kind of coordination of efforts to detect and track asteroids by various American organizations associated with the exploration and study of space, rather than creating a large, financially secure and technically armed department to solve this problem.
This coordination is carried out under the Spaceguard program. One of its goals was to detect, by 2008, 90% of asteroids with a diameter of 1 kilometer or more, which can potentially threaten the Earth. The program received rather modest funding. The question of continuing the search for potentially dangerous asteroids now with diameters of at least 140 meters is being considered with the aim of discovering at least 90% of them by 2028. True, achieving this goal will require the allocation of an amount from the US budget in the region of $ 250-450 million..
The “Task Force for Planetary Defense” was created and within the framework of NASA.
In Russia, this problem is not bypassed either. In June 2010, the Russian Academy of Sciences (RAS) hosted a joint meeting of the Presidium of the Scientific and Technical Council of the Federal Space Agency and the Bureau of the RAS Council on Space with the agenda: “On the organization of work to solve the problem of asteroid-cometary hazard.” In the speeches of the participants in the joint meeting of the Presidium of the Scientific and Technical Council of Roscosmos and the Bureau of the Space Council of the Russian Academy of Sciences, it was noted that:
– According to modern concepts, the threat of a collision of the Earth with threatening bodies (asteroids and comets) larger than 50 meters is a serious problem.
– The overall scale of the threat is assessed quite confidently, however, the degree of reliability of warning about a specific threat is unacceptably low, since a sufficiently powerful system for detecting dangerous space bodies has not yet been created.
In order to solve these problems, it was proposed to develop and implement an appropriate Federal Target Scientific and Technical Program (FTsNTP). This program should include the creation of a national system for the detection and study of dangerous bodies, the development of criteria for a reliable risk assessment, the creation of a system to counteract and reduce damage from the fall of large celestial bodies. The main efforts are supposed to be focused on two main areas: to create specialized space-based telescopes and space complexes for studying space bodies in situ (that is, vehicles for flights to asteroids).
True, given that the fall in oil and gas prices poses a much more serious threat to the survival of the Russian state than the fall of an asteroid on its territory, no real measures have been taken in Russia against the aseroid threat..
Bottom line: we follow, prepare, do not panic
Asteroids and meteorites have always hit the Earth. Just earlier, when there were significantly fewer people on Earth, fewer cities and man-made buildings, the probability of damage that the heavenly “fragment” could cause to civilization was negligible. Asteroids and meteorites, as already noted in the article, have become less in the solar system as a whole, but there are more places on Earth where their fall can leave a serious “wound” on the body of mankind.
And yet there is no reason to panic. It must be remembered that people already have the technology to create “tugs” (or “pushers”) capable of taking an asteroid off a trajectory dangerous for the Earth. The main task is to make out in time an object that has driven into the “oncoming lane”. Then there will be time to push it from there into the “ditch”, where it will not pose any danger to the Earth moving in its “strip”.
And of course, the creation of such an integrated system for the timely detection and removal of asteroids from the Earth is not a matter of one state, but of the entire international community, no member of which is guaranteed from receiving a “gift” like the Chelyabinsk.