Feb 14, 2013 2:39 PM GMT
A Warning From the Asteroid Hunters
The likelihood in this century of an asteroid impact with 700 times the destructive power of the Hiroshima A-bomb: 30%.
In the game of cosmic roulette that is our solar system, we just got lucky. Earth will get a very close shave on Friday, Feb. 15, when Asteroid 2012 DA14 passes just 17,000 miles from our planet. That is less than the distance from New York to Sydney and back, or the distance the Earth travels around the sun in 14 minutes. We are dodging a very large bullet.
The people of Earth also are getting a reminder that even in our modern society, our future is affected by the motion of astronomical bodies. The ancients were correct in their belief that the heavens affect life on Earth—just not in the way they imagined. Sometimes those heavenly bodies actually run into Earth. That is why we must make it our mission to find asteroids before they find us.
The last major asteroid impact on Earth was on June 30, 1908, when one about the size of an office building (140 feet across) slammed into Siberia with a destructive energy 700 times that of the atomic bomb dropped on Hiroshima. That asteroid devastated a region roughly the size of the San Francisco Bay area. Asteroid 2012 DA14, which will be passing over our heads on Friday, is about the same size as the asteroid that devastated Siberia's Tunguska region.
Many wonder about the odds that an asteroid may hit Earth in their lifetime. As it turns out, that is something scientists can measure quite well. We can count asteroids passing near the Earth using telescopes. We can count the number of craters on the moon. And we can count shooting stars in the sky, which are just small asteroids burning up in our upper atmosphere. We know how often asteroids of different sizes hit the Earth—and the odds of a dangerous one are cause for reflection.