Simulation of an asteroid strike by an atomic bomb in Spheral software. Credit: LLNL.
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In catastrophic films, we often witness the use of atomic bombs as a panacea for dangers of various kinds. As far as asteroids are concerned, the use of nuclear weapons is often questioned as ineffective or even counterproductive. However, according to a new study by American physicists, published in the journal Acta Astronautica, an atomic bomb on an approaching smaller planet could work.
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Patrick K. King. Credit: PK King.
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Experts call this late-time small-body disruption. And it’s eloquent. The point is, if for some reason there is little time for action against an incoming asteroid, we throw an atomic bomb at it. An analysis by a team led by Patrick King of Johns Hopkins University confirms that such a defense against the asteroid would be very effective, even if used less than a year before the asteroid’s anticipated collision with the Earth.
Planetka Bennu, leden 2019. Kredit: NASA/Goddard/University of Arizona/Lockheed Martin / Wikimedia Commons.
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According to King, modeling the behavior of fragments that appear after the explosion of a nuclear weapon is especially problematic. However, he and his colleagues managed it, with the help of Spheral software. They modeled situations in which we use a 1 megaton TNT nuclear missile against a planet 100 meters in diameter – about a third the size of the popular asteroid Bennu of Apollo’s group, which irritates us with close flyby of the Earth.
Of course, the researchers played with the model and tried different situations in which they destroyed the asteroid at different distances from Earth. It turned out that if we drop an atomic bomb on such an asteroid when it is 2 months away from Earth, we will reduce its destructive potential to only 0.1 percent of its original mass. If a larger asteroid were flying at us, an impact with a similar nuclear missile when it was 6 months away from Earth would reduce its impact mass to 1 percent, which is still a great result. But it would have to be a well-calculated and accurate hit, otherwise such an asteroid will turn into several smaller ones, which will hit more places on the earth’s surface.
The authors of the study emphasize that such an intervention is an emergency solution. It really should be the last line of defense. Of course, it would be better to detect the dangerous asteroid much earlier and subtly deviate it from its course so that it simply misses the Earth. Technologies that could arrange this have been working on for some time.
Literature
Acta Astronautica 188: 367–386.
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