Space Shuttle Atlantis; LAST RE-ENTRY:

On July 21st, the crew of the International Space Station photographed an event that will never be repeated: the re-entry of a space shuttle. Marking the end of NASA's 30-year shuttle program, Atlantis dove Earthward in a fiery arc that only six lucky space travelers could see from above:

The green band of light in the background is called "airglow." Airglow is a luminous bubble that surounds our entire planet, decorating the top of the atmosphere with aurora-like color. Although airglow resembles the aurora borealis, its underlying physics is different. Airglow is caused by an assortment of chemical reactions in the upper atmosphere driven mainly by solar ultraviolet radiation; auroras, on the other hand, are prompted by gusts of solar wind.

More pictures from the last flight of Atlantis may be found here.