Impact: Earth! A meteor/comet impact simulator(text only) provided by Purdue University. Lots of fun. You can smash things into the Earth varying the diameter, density, velocity, angle, land or water entry, and your distance from impact. 1 meter: very boring. happens every 1.1 year. Even if you are within 1 km, they claim you can't hear it. 950 km(Ceres!): also kind of boring, but I had the speed set at minimum. Though at 1000 km, you'll be hit by 50,000 mph winds, and be covered by 36 miles of "ejecta". The middling things are more interesting. And you can chose from a list. Apophis!: 260 meters My settings: 72 m/s, 90° entry, impacting sedimentary rock At 10km from impact: Max wind velocity: 1430 m/s = 3200 mph Duration of Irradiation: 1.39 minutes Radiant flux (relative to the sun): 1880 Sound Intensity: 130 dB (Dangerously Loud) Ha! Dangerously loud, so cover your ears, before you're hit by 3200 mph winds, and burst spontaneously into flames. Ha! Anyways, it's something to play with, if you're bored. ps. This came across on Facebook today. There was a related video apparently put together by the Discovery Channel, that lasts about 5 minutes. It's a simulation of a 500 km asteroid striking somewhere in the Pacific ocean. The music is very nice: The Great Gig In The Sky, from Dark Side of the Moon.