What the world needs now is not love, it's an airbag

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Fearful of a cosmic collision? Don't worry â“ the same thing that saves hundreds of lives on earth every day could save millions when used on a wayward asteroid. That is, an airbag.</p>According to Hermann Burchard, professor of mathematics at Oklahoma State University, a giant airbag several miles wide would be the best way to divert one of the hundreds of pieces of cosmic debris that from time to time threatens the planet.</p>The risk is real: three asteroids that could have caused significant damage, and perhaps killed thousands if not millions of people, have passed close to the earth in the past three months alone.</p>Scientists around the world are tracking hundreds of such "near-earth objects" looking for those whose orbits might cross ours, but they still face the question: if one is found, what next?</p>Some have suggested exploding a nuclear weapon close to the object in space. But that might have little effect: asteroids and comets are often loose aggregations of rubble. A nuclear blast might even create fragments, any of which could still pose a threat.</p>Professor Burchard said his airbag plan, by contrast, "seems a safe, simple and realistic idea", although he hasn't quite worked out the details â“ such as what you'd make it from.</p>Some details have been considered: the bag could taken, uninflated, by a spacecraft to the object. That is feasible; in February 2001 an uncrewed spacecraft landed on the asteroid Eros, though only after a five-year flight. The airbag could easily be inflated in space by gas from a chemical reaction. It could then be used to divert the rubble of an asteroid without breaking it apart.</p>But Erik Asphaug, a mathematician at the University of California, at Santa Cruz, says a simpler solution would be to attach a rocket motor to the object.</p>"Asteroids and comets are not so fragile that you can't touch them," he said. "They get cratered all the time and don't fall apart. So you just need to apply gradual thrust over time." </p>