The Milky Way surrounded by the rainbow glow of the atmosphere

Driving past Keluke Lake in the Chinese province of Qinghai a few years ago, the photographer saw the Milky Way stretching across the night sky and stopped to capture it. Only then did he notice that the sensitive camera recorded not only the galaxy, but also the glow of the atmosphere, which encircled the entire sky with rainbow stripes. The colors in the picture have been enhanced for greater clarity.

The atmosphere is always glowing due to various processes in its upper layers. But this glow becomes especially noticeable when it is disturbed by any activity, for example, in the case of an upcoming storm. The resulting gravitational fluctuations can be compared to circles on the water when a stone is thrown into it.

The red glow is presumably caused by the excitation of OH molecules located in the ionosphere above 80 km by solar ultraviolet radiation. The orange and green stripes probably originate from the sodium and oxygen atoms located even higher.