Nuclear bomb could save Earth from asteroid

(Space.com) A well-placed nuclear explosion could actually save humanity from a big asteroid hurtling toward Earth, just like in the movies, a new study suggests.

Scientists at Los Alamos National Laboratory, a United States Department of Energy facility in New Mexico, used a supercomputer to model nukes' anti-asteroid effectiveness. They attacked a 1,650-foot-long (500-meter) space rock with a 1-megaton nuclear weapon - about 50 times more powerful than the U.S. blast inflicted on Nagasaki, Japan, to help end World War II.

The results were encouraging.

"Ultimately this 1-megaton blast will disrupt all of the rocks in the rockpile of this asteroid, and if this were an Earth-crossing asteroid, would fully mitigate the hazard represented by the initial asteroid itself," Los Alamos scientist Bob Weaver said in a recent video released by the lab. [Video: Nuclear bomb takes out asteroid]

In the 3-D modeling study, run on 32,000 processors of the Cielo supercomputer, the blast went off at the asteroid's surface. So the nuke likely wouldn't have to be deposited deep into a threatening space rock, a dangerous job Bruce Willis and his astronaut crew tackled in the 1998 film "Armageddon."

Weaver stressed that nuclear bombs would likely be deployed only as a last resort, if an impact loomed just months away. And other researchers caution that a nuclear blast might have negative side effects, such as sending a hail of many small space rocks toward Earth instead of a single big one.

If humanity had more notice of an impending impact, there are several other asteroid defense strategies we might be able to employ, scientists have said.

For example, we could send a robotic probe out to rendezvous and ride along with the potentially dangerous asteroid. The spacecraft's modest gravity would exert a tug on the space rock as the two cruise through space together. Over months or years, this "gravity tractor" method would pull the asteroid into a different, more benign orbit.

We have the know-how to pull off such a mission. Multiple probes have met up with rocks in deep space, including NASA's Dawn spacecraft, which is currently orbiting the huge asteroid Vesta. And in 2005, Japan's Hayabusa probe plucked some pieces off the asteroid Itokawa, sending them back to Earth for analysis.

Humanity could also simply slam the rendezvous craft into the asteroid, relying on brute force rather than a gentle gravitational tug to push it off course. This impactor approach would not be as precise as the gravity tractor technique, researchers say, but it could still do the job under certain circumstances.

We've demonstrated the ability to accomplish this more aggressive mission as well. In 2005, for example, NASA sent an impactor barreling into the comet Tempel 1 to determine the icy object's composition.

Discussions about asteroid deflection aren't just academic exercises. Huge impacts are a part of our planet's history; one wiped out the dinosaurs 65 million years ago, and it's just a matter of time before another big space rock lines Earth up in its sights, astronomers say.

You can follow SPACE.com senior writer Mike Wall on Twitter: @michaeldwall. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

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[evlevi]

This will cause ROCK RAIN and can be surely less damaging but still very much scare humanity. Good news we can use ATOM BOMBS for outside threats then on earth...surely a pieceful demo of ATOM BOMBS should be used..

[mafritz0]

Yes, a nuclear bomb would indeed be a very efficient method of diverting a close asteroid. Even if the rocks continued on their course towards Earth, they would all be smaller in size and would burn up quicker on entry into the Earth's atmosphere. What we need to do now is test this on a real asteroid to see if it actually disrupts the rocks enough in the asteroid to accomplish our intentions. This finally could be a practical use for such a weapon.

[mafritz0]

Yes, a nuclear bomb would indeed be a very efficient method of diverting a close asteroid. Even if the rocks continued on their course towards Earth, they would all be smaller in size and would burn up quicker on entry into the Earth's atmosphere. What we need to do now is test this on a real asteroid to see if it actually disrupts the rocks enough in the asteroid to accomplish our intentions. This finally could be a practical use for such a weapon.

[glaziers8669]

Sounds like the dawn spacecraft might already be doing the space tug.Is vesta on coarse with Earth?

[themanfrombrum]

What if something goes wrong with the nuclear devise prior to hitting the asteroid? We're still going to be toast!

[waassup]

Look ahead 20 years, what's worth saving?

[KansasCity-2012]

The nuclear bomb option is science fiction, because in space, there is no matter for the explosive force to tamp against and divert the path of the asteroid.

[cwong99]

The nuclear bomb will be pushing against the asteroid... Energy is released in all directions which will push anything with mass. If want to know where the energy comes from, its a nuclear explosion. It comes from splitting atoms which is described in e=mc^2, which basically states that mass is made of energy and vice versa.

[bubbabob9]

The 'short-bus' school of physics is heard from.

[robert_holt]

"The second angel blew his trumpet, and something like a great mountain, burning with fire, was thrown into the sea, and a third of the sea became blood." Revelation 8:8. Hmm...I wonder...does that verse refer to an asteroid striking the Earth? Maybe, maybe not. It's an interesting thought though. 70 percent of the Earth's surface is covered by water and 30 percent by land. I suppose the possibility of an asteroid hitting the ocean would be greater. "For then there will be great tribulation, such as has not been from the beginning of the world until now, no, and never will be." Matthew 24:21. Just a thought, for what it's worth.

[Raptorsmasher]

It means nothing, for those writing the Bible were ordinary men who were trying to sell their religion with imaginary prose. It's just a made up story.

[DenverBroncofan]

They should wait and see where the projected landing zone would be. If it's Texas or the Middle East, let it land