New research suggests that the biggest danger in the event of an asteroid falling to Earth will not be the fact of its collision with the surface. The biggest threat to all of us will be the shock wave that the asteroid will create upon entering the atmosphere.
The results of the study, accepted for publication in the scientific journal Meteoritics and Planetary Science, indicate that most deaths from a sufficiently large asteroid will be caused by a blast wave upon its entry into the atmosphere. Moreover, regardless of whether it will be destroyed while still in airspace, or directly fall to the surface entirely. I don’t know if this news can reduce the degree of stress, but for the most catastrophic effect, the asteroid will need to enter the atmosphere near a densely populated urban area. The good news is that large asteroids hit Earth very, very rarely.
If we take the average statistical asteroid, then its orbital speed around the Sun is about 108,000 km / h (or about 30 km / s).
“At such a speed, when entering the earth's atmosphere, a colossal amount of energy will be created. The result will be the release of a very powerful shockwave,”says lead author Clemens Rumph of the University of Southampton.
"This event will be accompanied by the emergence of very powerful tornado-like winds descending to the surface after the asteroid, as well as the fall of many smaller debris created by this space object."
In some cases, it can completely collapse even in the atmosphere of the planet, but if the asteroid can maintain its integrity, it will eventually fall to the surface, forming an impact crater and scattering its debris mixed with soil and other debris for several kilometers around the area. Of course, one of the results of this event will be the beginning of the most powerful earthquakes. Definitely, this will not be the best day in the history of the planet, and especially for those unfortunate souls who are not lucky enough to live near the place of the fall.
To estimate the amount of mortality due to the asteroid threat, Rumph considered three possible scenarios for the development of events: taking into account the consequences caused by the asteroid, in which the object will burn up in the atmosphere before it hits the surface; taking into account the place of its fall to the Earth; and also taking into account its fall into the ocean and the resulting tsunami.
The diagram shows the different scenarios and their consequences.
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In his study, Rumph sketched various possible options for the entry and fall of an asteroid and, as an example, analyzed two of them in more detail. In the first case, he suggested what could happen if an asteroid 200 meters in size fell into the Atlantic Ocean 130 kilometers from the coastline of Rio de Janeiro. A similar event, Rumph said, would cause approximately 50,000 deaths. His calculations indicate that 75 percent of these deaths will be caused by the powerful tsunami that appeared after the asteroid fell. The remaining 25 percent are likely to die from the powerful shockwave from the air blast.
Earlier studies on the possible consequences also reported catastrophic effects of tsunamis, but in the study, Rumph assigns an important role to the continental shelves, which will serve as a kind of buffer, dissipating the main power of the tsunami near the hills and along the inclined shoals.
In the second scenario, Rumph considered the option in which the asteroid would fall in London and Berlin. In two cases, the culprits of the celebration are two different-sized asteroids - 50 and 200 meters, respectively - and two levels of impact are also considered: only in the presence of an air explosion of a shock wave or an air explosion together with the fall of an object. The results can be seen in the graph below. The estimated number of victims is highlighted in bold black numbers.
As you can see, in this case, we can talk about millions of dead. However, most of these casualties (approximately 85 percent) will be caused by air blast waves, even if the asteroid hits the ground, adding several hundred thousand more dead to the list. About 15 percent of residents will be killed by the heat generated by the shockwave. And the remaining number of victims will be associated with a sharp wave pressure, earthquakes, the very fall of the object and the debris of the asteroid.
Prospects are not pleasant, we must admit. It should always be remembered that events of this scale (the fall of large asteroids) occur, according to the calculations of the same scientists, approximately once every 400,000 years. Now, the only excuse that can at least somehow reduce the degree of anxiety is that most of the planet's surface is still unpopulated, so the probability of an asteroid falling over the city is at a relatively low level. And yet, maybe it really should be supported by scientists in their idea to shoot down dangerous objects with nuclear charges even on their approach to Earth?
NIKOLAY KHIZHNYAK