Aurora Borealis and Airglow seen from the ISS
Glowing Gases

The ISS was 237 miles above the southern Pacific Ocean Lat 49°S Long 86°W on January 18, 2003. The sun is making the atmosphere below glow in two different ways.

The smooth bubble following the earth's curve, green with a hint of orange beneath, is airglow. Extreme ultra-violet light from the sun excites the upper atmosphere and the airglow is the light from excited oxygen atoms (and here possible sodium atoms too). The excited atoms continue to give off their light long after darkness.

The tall, spiky Aurora Australis is also the glow of excited oxygen atoms but the result of upper atmosphere bombardment by eneregetic electrons. They come from outbursts on the sun and are trapped in the earth's magnetotail where magnetic reconnections occur that accelerate them downwards to the auroral ovals.

Image courtesy of the Image Science & Analysis Laboratory, NASA Johnson Space Center.