Impact Earth is a site created by Purdue University that allows you to set various variables for the size, speed, location, and material of an object crashing into Earth, and then see the effects.
For instance, if an object the size of the Moon crashed into 100 meter deep ocean at a speed of 11 kilometers per second, I would still die, even though I lived 5,000 miles away. That is how big the crater would be. That's just the experiment I ran though, you can play with all sorts of premutations.
Via The Corner
