On the Cover — Issue 38, Spring 2010

This space-station view of Los Angeles was taken by Astronaut Donald Pettit, who lived aboard the International Space Station for five and a half months. The city is defined by yellow-orange, sodium-vapor-lit streets in north–south, east–west grids. In between the main streets it is relatively dark due to the design of street lighting that minimizes stray light. Geographic features of coastlines and mountains remain dark. At the edge of town, the lights abruptly fade into the surrounding desert.