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Nature’s sci-fi blockbuster
by Kristin ArrigoMaybe our latest science fiction film obsessions have been getting us prepared for the CGI in the sky. That is, the natural occurrence of glowing clouds at night, or noctilucent clouds.
Usually appearing up at the polar regions, clouds will sometimes take on a glow where ice meets atmosphere. This summer, the clouds have been glowing at a lower range, very low, as in visible from North Dakota to Poland.
Greenhouse gasses and specifically the greenhouse gas methane could be to blame. As methane increases in the atmosphere, the amount of water that turns to ice in the stratosphere, full of cosmic dust, allows for clouds to glow at a lower level. Methane increases are typically due to farming and population increases. Higher greenhouse gas emissions result in mesosphere (middle atmosphere) cooling, which can cause the clouds to glow as well.
Yet another theory is that the noctilucent clouds are actually the product of Shuttle launches. The liquid hydrogen and liquid oxygen used as fuel has a by-product of 300 metric tons of water vapor.
A NASA satellite mission is studying the clouds, but information available is inconclusive. The reason being that changes occurring in the atmosphere happen very quickly, making it difficult for scientists to find all the answers. The study is planned to continue for three more years, during which time they hope to determine the exact cause.
Check out some of the following links and our Video thread for more on this sky-fi oddity.
Study finds space shuttle exhaust produces night-shining clouds (Earth Observatory)
Noctilucent clouds over Germany (NASA)
Scientists seek noctilucent cloud enlightenment (The Register)
Photo by mikeyscope.
Video by derickrethans.