nubbsgalore:the colours streaking through these night skies are from atmospheric airglow and the gra
nubbsgalore:the colours streaking through these night skies are from atmospheric airglow and the gravity waves passing through them. airglow is the result of chemiluminescence in the thermosphere, where ultraviolet radiation from the sun excites atoms, mostly oxygen and nitrogen, which emit photons as they collide to form new molecules like nitric oxide.to get a sense of the difference between the aurora and air glow - the latter is fainter, these photos the rare exceptions, and covers the whole globe, while the former is not the result of a chemical reaction - see this image.airglow can look rippled when gravity (or buoyancy, and not gravitational) waves pass through the atmosphere. whether from the updraft of a storm or air moving over mountainous terrain, a wave can form in a stable layer of the atmosphere, which grows as it rises from the lessening atmospheric pressure. it’s like putting your hand in water and forcing it upwards without breaking the water. the displacement creates a ripple in the water, like with a tsunami emanating from the spot of an earthquake, where one plate is thrusted upwards. photos were taken by yuri beletsky, marcko korosec, jeff zylland, jeff dai and chris cook. -- source link
#photography#space