NASA, who has until now been charged with finding and cataloging NEOs (AKA Near-Earth Objects) larger than 2,300 feet in diameter -- of which there are about 127 -- has had their mission changed. Congress recently decided that NASA's search was not sufficient, and should be expanded to include smaller objects, down to about 230 feet wide. It's estimated there are more than 20,000 of these potentially destructive and uncomfortably close asteroids flying around our solar system, and once NASA has the new array of telescopes online that will allow them to track these bodies, we'll probably find that a few of those 20,000 are indeed on extremely worrisome trajectories. "This has gone from being an esoteric statistical argument to talking about real events," said Dr David Morrison, an astronomer at the Nasa's Ames Research Center.
So what happens when we discover a deadly asteroid headed straight for us? Now that it's a possibility no longer relegated to bad late-90s sci-fi adventure movies (Deep Impact, Armageddon), the UN is getting involved. Ideas could include hitting the asteroid with a spacecraft or rocket to deflect its orbit (but wait, wasn't that what they tried in Armageddon?), or using a "gravity tug" that would simply hover over the asteroid and use gravity as a "towline" to change its path. Either way, expect a lot more gloom and doom from the world's space administrations in the future.