If a massive asteroid is hurtling toward Earth and threatening to sterilize the entire planet, blasting it to pieces with nuclear bombs might seem fit for a Hollywood movie. But, it could, in fact, be a viable solution to the potentially apocalyptic event, according to scientists who have studied asteroids and possible solutions to prevent Earth impacts. There are some strings attached: The interloping space rock would have to pose a definite asteroid threat to Earth in a relatively short timeframe to justify such a drastic option, the scientists said. And blowing up an asteroid runs the risk of creating more debris to worry about later, they added.
If an asteroid was expected to collide with Earth within the next 50 years, using nuclear explosives to divert or disperse the hostile space rock could be the best alternative, explained David Dearborn, a research physicist at the Lawrence Livermore National Laboratory in Livermore, Calif.
"The nuclear bomb is the strongest bomb we know," said Dearborn, who presented his study last month at the 216th meeting of the American Astronomical Society in Miami, Fl. "It's about 3 million times more efficient than chemical bombs. The question is how to use that energy."
The Lawrence Livermore National Laboratory, a research facility founded by the University of California, has programs that design and test nuclear weapons. [Top 10 Weapons in History]
Nuclear bangs in space
Dearborn believes that powerful nuclear explosives could be used to change the orbit of an asteroid heading for Earth, causing it to miss our planet and avoid a potentially devastating impact.
But, that nuclear option is most effective in circumstances where there are only a few years notice, said David Morrison, director of the NASA Lunar Science Institute and senior scientist for Astrobiology at NASA's Ames Research Center at Moffett Field, Calif., who has done extensive research on asteroid and comet impact hazards.
"If we have an asteroid that is really large, and we don't have more than a few years notice, nuclear is probably all we can do," Morrison told SPACE.com. "If it's a mile or smaller and we have 10 to 20 years warning, we probably won't go nuclear."
In such cases, scientists could opt to impact the asteroid with a ballistic rocket, sending the cosmic interloper off course.
At the moment, there is probably very little difference in terms of accuracy for both the nuclear method and ballistic method, said Morrison. But if using ballistic rockets to divert asteroids can be tested, it is possible that this technique could be more precise.
"If we test the ballistic impact, as people have proposed doing, then we can make it much more accurate than a nuke," he said.
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