Giant Asteroids Could Start Hitting Earth Once a DecadeS

If you missed last night's meteor in California, or last winter's exploding asteroid in Russia, you'll probably have another chance soon: Scientists now believe large asteroids, like the one in Russia, could strike Earth far more often than previously studies had indicated.

According to a soon-to-be-published study in Nature, asteroid strikes like the one that exploded over Chelyabinsk, Russia in February – which historically were thought to occur every 100-200 years – could now take place every 10-20 years, according to revised studies by scientists.

The idea of more Earth-bound space rocks the size of the Chelyabinsk asteroid, which, while just 60 feet wide, detonated with the force of 500,000 tons of dynamite and injured more than 1,000 people, has some experts concerned. The prospect "really makes a lot of people uncomfortable," Peter G. Brown, a professor of physics and astronomy at the University of Western Ontario, told the New York Times. But not as uncomfortable as the possibility of even larger space rocks hurtling into Earth.

Only 10-20 percent of the 450-foot-wide asteroids near Earth have been spotted by scientists. But just how bad would it be if a 450-foot asteroid hit our planet?

"You're not going to wipe out humanity," Edward T. Lu, a former NASA astronaut, told the Times, "But if you get unlucky, you could kill 50 million people or you could collapse the world economy for a century, two centuries." Reassuring!

But don't worry: Dr. Lu and his scientist buddies have a plan. They want to launch a B612 telescope, to be called Sentinel, into orbit to track 450-foot-wide-and-larger asteroids. The telescope would detect any large asteroids and hopefully give governments enough time to deter any headed for Earth, or at least plan for its impact.

"When you find out how many there are, you also find out where the individual ones are," Lu said. "Everything you discover you can either rule out as going to hit us or you say, 'Hey, we ought to look at this one more carefully.'"

[Image via AP]