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I guess we've all seen or heard about the movie Armageddon, where Bruce Willis and his minions had to detonate a nuclear bomb on an asteroid to prevent it from colliding with Earth.
Without going to analyze whether or not flying an asteroid would be a good idea, the truth is that there are thousands of boulders out there, some of them large enough to kill all of us.
That is why it is necessary to investigate effective techniques that allow the asteroids that may have a dangerous course and size for our survival to be diverted.
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If the asteroid is far enough from our orbit, a small push would be enough to displace the orbit minimally, but, in the sizes of space we are moving, the orbit of the asteroid could vary enough so that it is not a threat.
That is why NASA together with ESA are preparing a joint mission that consists of crashing a spacecraft against an asteroid and seeing how it affects its trajectory.
The mission is called DART (Double Asteroid Redirection Test) and plans to crash a ship against one of the two asteroids in a binary system, something like the moon of an asteroid, in order to study the effects it has from Earth.
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It is the asteroid called Didymos and its "moon" Dimorphos, a small asteroid about 160 m in diameter that orbits it forming a binary system.
The alleged test is scheduled for 2022, that is, around the corner, and if it turns out well it is good news because, it is only a matter of time that one of these monumental stones ends again with life on Earth.
More information:
https://www.nasa.gov/planetarydefense/dart
https://www.nationalgeographic.es/espacio/2020/04/la-mision-dart-por-que-la-nasa-intentara-desviar-un-asteroide
Versión en español