This is cool: An online calculator where you can figure out just how badly you'd die if a meteor hit the earth near you. You plug in how far away it would hit, what type of meteor -- "ice", "porous rock", "dense rock" or "iron" -- as well as the speed it's travelling and the angle of impact. Then click the button and, presto: The details of your own private eschaton.

I set it up for a half-kilometer-sized ball of ice, hitting the earth at a 35-degree angle and travelling 10 kilometers per second. The result? It would release 3.27 x 1018 Joules of energy, roughly equivalent to 7.82 x 102 MegaTons TNT, leaving a 5.2-km-wide crater. It would create a 6.5-Richter shock wave, and the "ejecta" -- stuff thrown in the air -- would hit 45 seconds later, with the chunks each being 12 feet in diameter.

The worst part? The "thermal radiation" cast by an object superheated as it ploughed through the atmosphere at such an awesome pace. The fireball would be 67.3 times larger than the sun, and would cause the following damage:

Much of the body suffers third degree burns
Newspaper ignites
Deciduous trees ignite
Grass ignites

Nice. Thank god this sort of impact apparently only happens every 19,000 years.