A Rain of (Teeny) Asteroids

Over the weekend, the Geminid meteor shower came to a peak. This annual event occurs when the Earth plows through debris left behind by the asteroid 3200 Phaethon as it orbits the Sun (it gets so close to the Sun that bits of the rock vaporize and blow off the asteroid). Each little bit of interplanetary detritus is moving at about 35 kilometers/sec (22 miles/sec), fast enough that as it rams through our air, it heats up enough to become incandescent, and we see a "shooting star." I was out Satu...