Go out on a clear summer evening, just after the sun has set completely. Face west and look up. High above the dark line of the trees and buildings, to where the rays still light up the twilight sky. Can you see faint clouds spread out as a kind of ethereal glow? If so, they are noctilucent clouds. You are looking into the mesosphere, that vast region between 15 and 70 km above the earth. Hardly anyone goes there except a few intrepid balloonists, jet pilots and astronauts on their way through. It’s incredibly cold, and emptier than the poles, the mountains of Central Asia and the depths of the Pacific. Noctilucent clouds are just about the only visible thing up there, and so, as its high summer ,we thought we’d collect a few pieces to let you enjoy them.
Stuart Clark has a nice general piece for the Guardian [1] and for background we have linked to the inimitable Wikipedia[2] Which comes with a warning. The clouds seem never to have been observed before about 1885, which may suggest some link or other to growing pollution.[3]
People pay big money to visit the vast and the remote, and endure terrible problems with the food and the plumbing as they do so. But here we offer you the chance to stand in awe to glimpse something bigger, vaster and even more remote. And it’s all for free.
Once again, we advise you to wait until well after sunset and not to look directly at the solar disc in any circumstances whatsoever
[2]https://en.wikipedia.org/wiki/Noctilucent_cloud
[3]https://www.theguardian.com/science/2022/jun/06/is-human-pollution-causing-clouds-to-form-near-the-edge-of-space
#noctilucent cloud #mesosphere #atmosphere #pollution #night sky
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