Mass starvation and the death of billions
A scenario that has been worrying humanity for a long time is the fall of a giant asteroid to Earth, which can change the entire earthly reality. What is there — to destroy all living things. After talking with astronomers, we found out how big the risk of such a situation is and how it can be prevented.
While we are sleeping or awake, cosmic «messengers» fly over us. They can be iron, stone, less than a meter, the size of a football field or a mountain. It was with a field 100 meters long that the asteroid 2023 DZ2 turned out to be, which flew 160 kilometers from Earth on the night of March 25-26.
Every day up to 100 (!) tons of matter falls to the Earth from space. These are stones from a few grams to tens of tons, such as, for example, the largest of the meteorites — the 66-ton Goba, found in 1920 in Namibia. The main external signs of a meteorite are the melting crust, depressions on the surface and magnetization. Also, meteorites tend to be irregular in shape.
According to the chief researcher of the Ural Federal University, a member of the Commission on meteorites of the Russian Academy of Sciences Viktor Grokhovsky, despite the fact that star showers from meteors associated with comets “shed” on our planet several times a year, most often on Earth they still find stone meteorites of asteroid origin.
Knowing the speed with which they enter our atmosphere, we can assume their future fate — they will evaporate, forming a huge crater, or they will remain for millennia, and the crater will be small in size, about the stone itself is as large as in the case of Goba.
The meteor body, entering the Earth's atmosphere at high speed, greatly loses mass. Weighing initially from several tens to hundreds of tons, after passing through the dense layers of the atmosphere, it retains only a few kilograms or even grams of matter.
I wonder from Viktor Grokhovsky why recently we have begun to hear more often about falling meteorites.
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– Astronomers have long learned to find asteroids in the sky with a diameter of several hundred meters or more. As for the «stones» of smaller sizes — several tens of meters — «hunting» for them has become possible only since 2008, with the advent of more sensitive optics.
Today, there are seven of them, three of which even managed to find on Earth: the first in 2008 — in the territory of Sudan, the second in Botswana, the third — in the north-west of France. In the latter case, a 100-gram fragment remained from the original celestial body of a meter diameter after passing through the dense layers of the atmosphere.
— Defined. It was supposed to land near the city of Belaya Tserkov, maybe a little north of it, towards Fastov.
The most famous Russian fireballs, reminiscent of Kiev in size, from which meteorites could remain: two meteors were recorded in Mordovia and Mari-El last autumn, the third — in the Krasnoyarsk Territory. All three, most likely, fell in a forested area. Unfortunately, it is not yet possible to establish their exact coordinates, since Russia does not have its own so-called fireball network.
— The Chelyabinsk meteorite with a diameter of about 19 meters and a mass of about 13 thousand tons in our century is the largest event of this type on the planet.
We can find some of the asteroids that are similar in size to it, but not all, because we don't have the technology to cover the whole sky. One telescope surveys such a small segment of the sky, which, by analogy with photography, can be compared with only one pixel. By the way, in the West, too, they cannot always track such asteroids.
— At the recent scientific readings dedicated to the decade of the meteorite fall, both our and American scientists made a lot of reports. Several of them were devoted to the past of our famous meteorite.
In particular, some researchers determined by its texture that, flying for billions of years in space, it collided with other bodies of the solar system 6-8 times.
But we, having conducted an experiment, showed that, in principle, such a remelted texture could be obtained with one blow. Our study is more in line with the work of the Japanese scientist Nakamura, who claims to have found minerals containing water in the substance of the Chelyabinsk meteorite. If this is confirmed, it would mean that the asteroid had an encounter with a comet before heading towards Earth.
– It is possible.
– It has been observed that they fall to Earth on average once every half a century. The Chelyabinsk meteorite can be compared with the Sikhote-Alin meteorite that fell in Primorsky Krai 76 years ago, or with the Tunguska event that occurred almost 115 years ago.
As for those larger bodies, they fall much less frequently. For example, the Arizona crater with a diameter of one kilometer was formed over a thousand years as a result of the fall of a 50-meter meteorite.
— Of course. According to an international database, there are already 32 thousand of those that approach the Earth and cross its orbit. They are constantly monitored.
However, to observe is one thing, and to be able to respond in time to the threat, to ward off the blow of a “mountain” flying from space, is still beyond the power of anyone.
Last autumn, the Americans conducted only the “first test of planetary defense”: they shot down Orbits of the asteroid Dimorph, 11 million kilometers from Earth… Meanwhile, everyone understands that it is impossible to stop — after all, there is not a single body in the solar system that would not be attacked by other cosmic bodies.
Astronomers associate not only the cratered Moon with meteorite impacts, but also Uranus “lying on its side” (whose axis of rotation is knocked down so much that it is almost parallel to its orbit), and the absence of a whole planet between Mars and Jupiter, which could also be destroyed by a large asteroid .
Our planet, fortunately, is still intact, but scientists have evidence that it has already met with giant meteorites. This can be evidenced by the largest 300-kilometer crater under the Antarctic ice, there is also a crater over 100 km in diameter in Yakutia…
Around the same time that the craters were formed, life on Earth, according to geological data, was subjected to significant tests. So, science knows that 65 million years ago, as a result of a collision with a large celestial body, most likely a comet, more than 75% of all life on our planet died out. And this situation can happen again.
Of course, serious disasters, for example, those that, according to the well-known theory of Luis Alvarez, occur once every 7 million years and kill everyone, we cannot prevent, but we must be prepared to reduce catastrophic consequences as much as possible.
As we know, even the Chelyabinsk meteorite brought real material damage, people suffered. It was a local disaster.
Employees of the Institute of Astronomy of the Russian Academy of Sciences in the work “Threat from the sky. Rock or Chance? defined catastrophes on another level. Thus, the fall of a celestial body to Earth with a diameter of several hundred meters to 1.5 kilometers would cause consequences similar to the largest earthquakes, “explosions” of volcanoes, or even a “limited nuclear war.”
“In the ocean, with such falling would form grandiose waves — a tsunami. Destruction and fires could cover millions of square kilometers (up to the whole continent). Scientists attributed such consequences to a regional catastrophe.
The consequences of a celestial body falling to Earth over 1.5 kilometers would cover the entire globe, that is, the catastrophe would become global.
Of course, the frequency of falling meteorites of a large size is small (in the table of global sources of death of people, this one is only in 12th place, after diseases, wars, epidemics, famine, accidents, suicides, hurricanes, poisonings and earthquakes). But with each such fall, destruction and casualties on Earth can be significantly greater than with all other disasters.
The fall of a large body to Earth, according to scientists, is capable of causing death of people within a few months or years. Based on the results of a nuclear weapon test, scientists have shown that a similar explosion from a huge asteroid impact (1-2 km in size at a speed of 20 km/s) will produce enough dust in the atmosphere that it will cause a decrease in temperatures over most of the land by a few degrees Celsius. Together with other effects: the destruction of the ozone layer, the poisoning of soil and water by acid rain, the death of crops, all this can lead to mass starvation and the death of several billion people, destabilizing the entire human civilization.
What if a dangerous body that threatens the Earth has already been identified?
Some offer everything for this case time to keep thousands (!) kilotons of charges on alert for an emergency repulse of an attack, that is, to have a nuclear bomb at hand that can change its trajectory.
There is a proposal to send a spacecraft with a jet engine to the body and «tow» the dangerous block to another trajectory. We and the Americans have many similar ideas and proposals. But without a coherent planetary defense system, they will all be useless. After all, an asteroid or a comet must first be tracked, and the trajectory must be accurately calculated over several years.
NASA and the European Space Agency have long had a comprehensive program to predict and prevent threats from the sky. How will Roscosmos respond?
Today, Russia has an Automated Warning System for Dangerous Situations in Near-Earth Space (ASPOS OKP), but a new, more modern one has long been expected to replace it.
Everything goes to the fact that at the end of this year there will be a project of a system of information and analytical support for the safety of space activities in the near-Earth space «Milky Way». It will work to prevent all threats from the sky, including meteorites and space debris.
In mid-April, it became known that the program was approved by the president of the country. Whether the Milky Way has something in common with the Strategic Defense of the Earth, which was once proposed by the previous general director of the state corporation Dmitry Rogozin, is unknown.
It is assumed that the Milky Way system will consist of 65 ground-based telescopes and a satellite groupings for monitoring near-Earth space. It will be conducted not only from the territory of Russia, but also from the territories of South America, the Middle East, Asia and other regions of the planet.