We saw the movies (Deep Impact, Armaggedon) but on April 13, 2036 we might get to see the real thing. That's when the 1000-foot-wide asteroid Apophis could smash into our planet with enough force to wipe a small state off  the map.

Scary stuff really but don't hit the panic button just yet. The odds of a collision are 1-in-6,250. Still, astromers aren't taking this threat lightly. Apophis poses the most imminent threat from the worst type of natural disaster known.  

If Apophis does make a direct hit on an urban area, the resulting destruction will be greater than Hurricane Katrina, the 2004 Asian tsunami and the 1906 San Francisco earthquake combined.  Another way of looking at it: the blast would equal 880 million tons of TNT or the power of the Hiroshima atomic bomb magnified 65,000 times!

While objects this size are estimated to hit Earth about once every 1,000 years, the chances of dying from a space rock is about the same as that posed by tornadoes and snakebites. "Certainly we had a major credibility problem at the beginning -- a giggle factor," said NASA. "Now, many people are aware this is something we can actually deal with, mitigate and defend against." Congress has already directed NASA to come up with options for deflecting potential threats from space. So far, the ideas include lasers on the moon, futuristic "gravity tractors," spacecraft built for ramming incoming asteroids, and nuclear weapons. 

Apophis is not a lone space menace. The newly discovered Asteroid 2006 HZ51, a 2,624 feet behemoth, has a 1-in-six million chance of hitting earth. Its ETA: as early as June 21, 2008.