A Smoke Angel from Airplane Flares
Credit: Russell E. Cooley IV, USAF
Explanation: What type of cloud is that? It is not a naturally occurring one. Looking perhaps a bit like a gigantic owl monster, the cloud pictured above resulted from a series of flares released by an air force jet over the Atlantic Ocean in May. The jet that released the flares, a C-17 Globemaster III, is seen on the right. The flares release smoke and the resulting pattern is sometimes known as a smoke angel. The circular eyes of the above smoke angel are caused by air spiraling off the plane's wings and are known as wingtip vortices.
From APoD, the Astronomy Photo of the Day