Resembling a sprawling nebula viewed through a telescope, noctilucent clouds blanket the lower third of the west-northwest sky an hour after sunset on June 27, 2021.
“Since mid-June I've been on a vigil. Every clear night at 9:55 p.m. I drive to a nearby location with an unobstructed view of the northern sky hoping to see noctilucent clouds. Half terrestrial and half celestial, these night-shining clouds form around 80 kilometers up in the mesosphere, far above the feathery cirrus and cauliflower cumulus of a summer's day. Lower clouds literally appear out of thin air when water vapor condenses on specks of dirt, salt, and industrial pollutants. Noctilucent clouds (NLCs) instead use soot shed by incoming meteoroids and, in some cases, sulfur-rich volcanic gases for that purpose. ...”
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