Double helix cloud contrail spotted near Moscow.on December 24, 2012. It is not entirely known what caused such a phenomenon. According to Wiki, contrails or vapour trails are long thin artificial clouds that sometimes form behind aircraft. Their formation is most often triggered by the water vapour in the exhaust of aircraft engines, but can also be triggered by the changes in air pressure in wingtip vortices or in the air over the entire wing surface.
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Photo: There's debate over whether the expression "it's a doozey" has anything to do with Duesenberg, but this 1929 Duesenberg Model J is all the evidence I need. http://en.wikipedia.org/wiki/Duesenberg#Etymological_note