"To the surprise of some, Mt. Etna emits, on occasion, smoke rings. Technically known as vortex rings, the walls of the volcano slightly slow the outside of emitted smoke puffs, causing the inside gas to move faster. A circle of low pressure develops so that the emitted puff of volcanic gas and ash loops around in a ring, a familiar geometric structure that can be surprisingly stable as it rises. Smoke rings are quite rare and need a coincidence of the right geometry of the vent, the right speed of ejected smoke, and the relative calmness of the outside atmosphere."
Fourteen years ago I noted the creation of a smoke ring by the Eyjafjallajokull volcano in Iceland. Exploding transformers on power poles can create the same effect.
The crescent moon (and colors and clouds and silhouette) is what makes that photo. I may have to do some post-editing to see what that looks like w/o the smoke rings?
ReplyDeleteThat picture is beautiful as it is but I want to do a zoom-in that ends with Ian McKellan as Gandalf sitting back against the rocks.
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