Those kinds of smoke rings are fairly common. The smoke is trapped in the narrow core of a much larger ring-vortex. It's laminar, otherwise the smoke would appear as a whirling cloudy structure.
I heard that some local guys ten years ago set off a homemade gasoline bomb in a parking lot. They said that its fireball created a perfect black ring which lasted for over an hour, rising the whole time. A common anomaly in actual volcanoes is "steam rings," vast laminar smoke rings launched outwards from vents. Mount Etna does it all the time. Go find some pictures (I see a sharply-defined laminar one, and a cloudy turbulent one, both white steam.) Also, http://www.abovetopsecret.com/forum/thread413894/pg1 On Wed, 17 Jun 2009, Terry Blanton wrote: > Whatever this UFO was, it scared the family: > > http://www.cnn.com/video/#/video/us/2009/06/16/dnt.va.ufo.sighting.wavy > > France, Brazil, Denmark and others have recently opened their UFO > files. Is some sort of disclosure underway? > > Terry > (((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billb at amasci com http://amasci.com EE/programmer/sci-exhibits amateur science, hobby projects, sci fair Seattle, WA 206-762-3818 unusual phenomena, tesla coils, weird sci
