Tuesday, March 20, 2007

Could lasers zap away dangerous asteroids?

Space lasers that zap away rogue asteroids may still be in the realm of a video game. But researchers say the technique could one day be used to and deflect asteroids that could impact the Earth.

Previously, researchers have proposed several methods to save Earth from an asteroid impact. These include blowing it up with a nuclear bomb or putting a spacecraft beside it so the craft's gravity could tug the asteroid off course.

But these solutions have drawbacks – the smaller chunks of rock created in the nuclear explosion might still threaten Earth, and the 'gravity tug' would require a relatively massive spaceship with a lot of fuel.

Now, researchers say a lightweight, space-based laser could eliminate these problems gradually altering the trajectory of a threatening asteroid. Though the technology may take two decades or so to mature.

One of the great advantages of using lasers is that their beams remain relatively tightly focused over long distances, allowing them to study asteroids from farther away than is currently possible.

The laser could be fired in short pulses, focused on a centimetre-sized spot on the asteroid, they would repeatedly pulverise material, ejecting tiny bits of space rock at 10 kilometres per second. This would function as the asteroid's propellant, pushing it into a different orbit – and safely away from Earth.

submitted by Shaun Saunders

1 comment:

Anonymous said...

right off the bat, I am going to disagree with this article in small fact. The gravity tug would be massive, but not as massive as they would suggest. Because its not the size of the hammer you wield, but how you wield it. Objects in space attract. The sun and earth attract each other. One more than the other, true...but the perturbations of the sun due to Earth's orbit are measurable. So if the Earth can move the Sun....then a small space craft is perfectly capable of moving ANY size asteroid, given enough time.