Atmospheric airglow
Atmospheric airglow
Earth is surrounded by various layers that emit their own light – a phenomenon known as airglow. The brightest emission comes from excited hydroxyl molecules, a compound of oxygen and hydrogen (OH). OH airglow is visible here in yellow and spans an altitude range of approximately 80 to 100 kilometres. The graphic also shows light emissions from excited oxygen atoms at the edge of space (green) and at altitudes of 200 to 300 kilometres (red).
Credit:
NASA