RIGHT SPEAK: The U.S. Takes Asteroid Threat Seriously

Some U.S. nuclear-warhead components, scheduled for disassembly in the next year, have gotten at least a temporary new lease on life. The reason: possible use in defending the Earth against killer asteroids.

A meteor streaks through the sky over Chelyabinsk, about
1500 kilometers east of Moscow on Feb. 15, 2013

That bit of information was tucked deep inside a 67-page Government Accountability Office report on the National Nuclear Security Administration, which manages the U.S. atomic-weapons arsenal. The warhead components, containing highly enriched uranium, are being retained "pending a senior-level government evaluation of their use in planetary defense against earthbound asteroids," the April report said.

An NNSA spokesman declined to comment.

The wall of a zinc plant was damaged by a shockwave
from a meteor in Chelyabinsk, Russia, last year.
Agence France-Presse/Getty Images

Government officials and space scientists say we aren't anywhere near a real-life replay of "Armageddon," the 1998 science-fiction extravaganza in which actor Bruce Willis and friends used a nuclear weapon to smash apart a giant asteroid hurtling toward Earth. While hundreds of asteroids with a diameter of about a kilometer or bigger—the size that could "produce global devastation," according to a 2010 National Research Council report—pass relatively near the Earth's orbit, none are expected to be a worry for at least 100 years and probably much longer, they say.

However, while no such mega-space rocks are on the horizon, an estimated 100,000 or more asteroids at least 50 meters in size also pass through Earth's neighborhood, said Lindley Johnson, a program executive at the National Aeronautics and Space Administration who oversees the effort to find such "near-earth objects." Probably no more than 5% of those objects have been catalogued so far, he said.