From the International Space Station, the aurora seems to set the Earth alight with green fire. This photo, snapped by the Expedition 32 crew aboard the ISS on July 15, 2012, offers a stunning view of the aurora australis, or southern lights. (That's Canadarm2, a robot arm extending off the station, in the foreground.) The southern lights, and their cousin the northern lights, occur when particles from the sun hit atmospheric gases, exciting the gas molecules and creating the gorgeous, twisting colors that can be seen at high and low latitudes.