Scientists from the Institute of Dynamics of Geospheres (IDG) of the Russian Academy of Sciences have created a model describing the consequences of the fall of large cosmic bodies over 30 meters into the Earth. Scientists have compared their calculations with observation data of the fall of the Chelyabinsk space body in February 2013. The results of the work carried out with the support of the Russian Science Foundation (RSF) are published in the journal Planetary and Space Science.
Large space bodies, the mass of which is tens of thousands of tons, rarely fall on our planet. The most famous case of this kind in recent decades was the fall of the Chelyabinsk meteorite on February 15, 2013. Scientists estimate the initial size of the body that entered the atmosphere at 17 meters, and its mass at 10,000 tons. The power released was several hundred kilotons in TNT equivalent, which is 20 times more powerful than the bomb dropped on Hiroshima. There were no fatal consequences because the explosion occurred at a high altitude, and its energy was scattered over a vast area.
The staff of the IDG RAS analyzed the observational data of natural and man-made disasters and developed a set of numerical models with the help of which they estimated the dangerous consequences of large space bodies falling to the Earth.
The main damaging factors that pose a danger to people and economic objects and were taken into account in the model are the parameters of the shock wave (its pressure and the speed of the wind caused by it), thermal radiation, atmospheric disturbances, including ionospheric disturbances (disturbances in the upper part of the atmosphere, saturated with ions and free electrons).
Scientists used a fluid model to describe how large space bodies are destroyed in the atmospheres of planets. When a space object is decelerated, it releases energy and deforms at altitudes where the aerodynamic load (air pressure) significantly exceeds its strength, so it collapses and is considered a fluid (or a body consisting of sand).
Destruction of the Chelyabinsk space body in the atmosphere. H - flight altitude in km. Not evaporated substance is shown in red, gray - vapors and air (a darker color corresponds to a higher density) / Valery Shuvalov / indicator.ru
“The limit of applicability of our model is objects over 30-50 meters, but we were able to describe the transient case of the Chelyabinsk meteorite quite well. It turns out that the model is applicable to all bodies that can bring more or less significant destruction. We can predict the characteristics of the shock wave, the size of the zone of destruction and massive fires, the amplitude of ionospheric disturbances, the size of the formed crater,”said one of the authors of the work, Doctor of Physical and Mathematical Sciences, Head of the Laboratory for Mathematical Modeling of Geophysical Processes, IDG RAS, Valery Shuvalov.
According to the assurances of experts, the likelihood of the fall of such cosmic bodies as the Chelyabinsk and Tunguska (about 60-80 meters in size) is extremely small, but even the most powerful telescopes cannot detect them promptly. Currently, astronomers track most of the cosmic bodies, the diameter of which is measured in kilometers. Their fall can be predicted long before approaching the Earth.
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“There are a lot of objects with a diameter of several tens and hundreds of meters, and it is almost impossible to detect them at the moment. The Chelyabinsk space body was still quite small, but the Tunguska one, whose diameter was a little less than 100 meters, was capable of destroying a large metropolis, such as Moscow,”comments Valery Shuvalov.