Time lapse aurora from ISS, HD
Taken from ISS of northern hemisphere night pass showing aurora (red 630nm and green 557nm emissions), atmospheric airglow (scale height of the atmosphere is about 100km in the movie), cities at night, star motion, and lightening. One image taken every 15 seconds and played back at 5 frames per image. The light emission is caused by trapped electrons and protons from Earth's magnetosphere impacting the upper atmosphere. At 100km altitude, the atmosphere is composed mostly of molecular nitrogen (N-N), molecular oxygen (O-O), and atomic oxygen (O). A life of a hapless electron (or proton) starts at the suns surface, is swept away by the solar wind, happens to get caught in the Earths magnetic dipole, bounces endlessly from North magnetic pole to South magnetic pole for months or years, and then on this evening has enough energy to overcome the retarding magnetic mirroring effect of the dipole field and impact a neutral gas particle in the upper atmosphere, which emits a photon of light that is then detected by Dr. Pettit's camera on the ISS orbiting at ~200km altitude. What a journey!