October 28, 2013
Millions of years ago, an object from outer space impacted our planet and wiped out over 50 percent of all life, most notably the dinosaurs. Be it an “act of God,” or just a forced form of natural selection, most people assume that something like that could never happen again. Unfortunately, they could not be more wrong. Just last year, a 20 meter diameter meteorite weighing 10,000 tons exploded over Chelyabinsk, Russia and killed almost 1,500 people, and compared to many of the free floating objects out in space that could cross paths with Earth’s orbit, this was a relatively small meteorite. Much larger ones, some of them very capable of repeating that cataclysmic event that wiped out the dinosaurs, are out there and may one day end up on an impact trajectory. Of course, if anyone has seen the film Armageddon then you are familiar with the idea that this sort of thing could happen. Unfortunately, unless you want to throw Bruce Willis and Ben Affleck into a rocket and have them try to blow the thing up, we need to come up with a different solution to this potentially apocalyptic problem.
Frank Schäfer of the Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institute in Freiburg has been conducting research on the possibility of deflecting asteroids by hitting them with large objects at high speeds (such as directed space probes) similar to how, in pool, one ball hits another and causes the second ball to alter its course. “During impact,” says Schäfer, “not only does the probe transfer its own momentum to the asteroid, there is also the recoil of detached material from the crater, which is ejected against the direction of the impact. This recoil effect acts like a turbocharger on the deviation of the asteroid.” According to his research, the total momentum that is transferred to the asteroids upon impact is up to four times greater than that of the deflecting probe. For the testing, researchers have created fake asteroids that share as many qualities with real asteroids as possible using things like dense quartzite, porous sandstone, or airy concrete, and impact that will small aluminum projectiles that act as the deflecting probe. What these tests have shown is that, scaling up, the impact of a probe would be enough to deflect the trajectory of an asteroids by a few centimeters per second, which would be more than enough to cause it to miss the Earth so long as the probe was fired off and impacted with the asteroids early, say several years before the possibility of impact. That might sound astronomical, pardon the pun, but it is entirely feasible, giving us a potential strategy should such an event seem imminent.
So, it’s not quite Armageddon, but given how the movie went, that’s probably a good thing.
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