Here’s an amazing new video from NASA of “airglow” and auroras. Here’s how Wired describes it:
The night can never be completely dark. Take away city lights, the moon, and the stars, and the sky itself will still produce a faint radiance.
Known as airglow, the diffuse phenomenon is beautifully captured in this new time-lapse video of Earth from space, which also features exquisite shots of the upper atmosphere and auroras.
A variety of chemical and nuclear processes create airglow, including cosmic rays striking the upper atmosphere and atoms combining together and emitting photons.
Each different activity produces a distinct color. The yellow color is generated when meteors break up in the atmosphere, leaving a layer of sodium atoms that produce golden light. The adjacent green layer comes from nitrogen and oxygen combining in a process that spits out green photons. Red emissions, seen higher up, come from excited –OH ions while a faint blue luminescence is formed by excited oxygen molecules.
I’m adding it to The Best Images Taken In Space.