Between these amazing shots and his many wacky microgravity experiments, it's abundantly clear that International Space Station astronaut Don Pettit has perhaps the coolest job on (and off of) this planet. Here's his collection of long exposure "star trail" photographs that transform the Earth and the cosmic firmament into a pachinko parlor. Behold Pettit's shots desktop-sized below, and here's his explanation of his shooting technique:
My star trail images are made by taking a time exposure of about 10 to 15 minutes. However, with modern digital cameras, 30 seconds is about the longest exposure possible, due to electronic detector noise effectively snowing out the image. To achieve the longer exposures I do what many amateur astronomers do. I take multiple 30-second exposures, then ‘stack' them using imaging software, thus producing the longer exposure.