This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Readers of a certain age will remember a golden era of asteroid films, capped by two with very different endings. "Deep Impact" drove home the devastating consequences of letting a large piece of rock hit our planet, whereas "Armageddon," though arguably the kitschier of the two films, was an uplifting story about technical ingenuity and sacrifice.
Now, the central premise of that movie's storyline—essentially blasting an asteroid with a nuclear detonation—is taking center stage as our last line of defense against a potential "Deep Impact" scenario. A new paper from researchers at the China Academy of Launch Vehicle Technology, published in Space: Science & Technology, describes two potential scenarios examining how we might actually be able to nuke a space rock—and whether it would save us. But before we get into the technical details of nuclear explosions, let's set the stage for the threat we face.
As of July 2024, 10,933 of the 35,269 near-Earth asteroids (NEAs) discovered have diameters larger than 140 m (460 feet). If one of those rocks happened to be on a collision course with Earth (which, to be clear, none of the known ones are), it could cause continentwide or even global devastation, resulting in the deaths of millions of people. Terrifyingly, asteroid defense experts consistently warn that simulations show there are a massive number of undiscovered NEAs that could easily blindside us.
In some cases, the warning time between an NEA's discovery and impact could be as little as a few days. That doesn't give us a whole lot of time to mount a defense. So it's best if we plan it out beforehand—and modeling is one of the easiest ways to do that.
With such a limited amount of time between discovery and impact, the only way we would have a chance of saving a large portion of the planet would be by imparting as much force as possible to the asteroid in an effort to either break it apart or drastically change its orbital path. And the best way we know to do that is by hitting it with a nuke. The new paper examines two potential ways of doing this.
The first is the simplest and fastest: simply fly a nuclear weapon into the side of an asteroid and detonate it with the right timing to knock it off its orbital path. This is quick, dirty and could work, but it also comes with major downsides. In this fast scenario, selecting an ideal site for the nuclear impact is impractical, and the "coupling energy" (i.e., the energy transferred from the blast to the asteroid itself) might be relatively weak.
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