Nuclear bombs may save us all

Experts debate the use of nuclear weapons to deter an Earth-killing asteroid.

By

Katherine Butler

Mon, Jun 28 2010 at 2:00 PM

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NASA

LIFE SAVER? An artist's concept illustrates a dead star surrounded by a disintegrating asteroid. (Photo: NASA)

Nuclear weapons have long been the bane of peace activists and politically unstable rogue countries. Now, space experts are debating their use to deter a catastrophic asteroid collision. Space.com reports on the pros and cons of using a nuclear weapon to push an asteroid away from the Earth — and perhaps saving all life in the process.

Michael Bay’s 1998 film “Armageddon” showed strapping oil-rig drillers flying to an asteroid, drilling deep into its surface, and detonating a nuclear bomb to send it flying in pieces around the Earth. Some scoffed at the idea as just another fantasy dreamed up by Hollywood. But others say there is some validity to the concept.

David Dearborn is a research physicist at the Lawrence Livermore National Laboratory in Livermore, Calif. As he recently told Space.com, “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.”

Using a nuclear weapon against an asteroid makes sense because this is the most efficient use of energy known to man. As Dearborn points out, "[Nuclear energy] is about 3 million times more efficient than chemical bombs. The question is how to use that energy." A nuclear weapon could either change the path of an asteroid or send it hurtling in pieces around the Earth.

However, using a nuclear weapon against an asteroid comes with difficulties. Asteroids have extremely low gravity, which complicates exactly how they would be diverted in space. As mentioned, a nuclear weapon would also likely fragment an asteroid, creating a problematic debris field. This debris field may not be an Earth-killer, but the fragments could do significant damage. This means that the asteroid would have to be hit at a safe distance from Earth, which Dearborn estimates would be just beyond the orbit of the moon.

Due to these complications, using a nuclear bomb on an asteroid is considered a last resort. Will they use one against the asteroid Apophis, which is scheduled to barrel towards the Earth at more than 28,000 mph on April 13, 2029? Scientists are 99.7 percent certain Apophis will pass at a close distance.

While some feel that the threat is tiny, others are taking it seriously. Famed Apollo 9 astronaut Rusty Schweickart told Popular Mechanics that he has been urging NASA to act on Apophis. Schweickart is co-founder of the B612 Foundation, an organization with a goal to alter the orbit of an asteroid, in a controlled manner, by 2015. According to Schweickart, "If we blow this, it'll be criminal."

In the meantime, at least we still have Hollywood to save us.