February 14, 2013
A WARNING FROM THE ASTEROID HUNTERS:
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. . . .
The chance of another Tunguska-size impact somewhere on Earth this century is about 30%. That isn’t the likelihood that you will be killed by an asteroid, but rather the odds that you will read a news headline about an asteroid impact of this size somewhere on Earth. Unfortunately, that headline could be about the destruction of a city, as opposed to an unpopulated region of Siberia. . . .
The chance in your lifetime of an even bigger asteroid impact on Earth—with explosive energy of 100 megatons of TNT—is about 1%. Such an impact would deliver many times the explosive energy of all the munitions used in World War II, including the atomic bombs.
Worth guarding against.