Comet collision!

"In July 2005, NASA's Deep Impact probe collided with comet Tempel 1, providing the first-ever glimpse of the interior of one of these "dirty snowballs" and valuable insight into the formation of our solar system. NASA's brilliant, but risky, plan to send a tiny, copper-plated probe hurtling directly towards the city-sized comet at a speed of 23,000 mph was a smashing success. The resulting explosion of particles provided experts with new data ab...