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Sunday, June 12, 2005

Reading List: Ball Lightning

Stenhoff, Mark. Ball Lightning. New York: Kluwer Academic / Plenum Publishers, 1999. ISBN 0-306-46150-1.
Reports of ball lightning--glowing spheres of light which persist for some number of seconds, usually associated with cloud to ground lightning strikes during thunderstorms, date back to the classical Greeks. Since 1838, when physicist and astronomer Dominique Arago published a survey of twenty reports of ball lightning, a long list of scientists, many eminent, have tried their hands at crafting a theory which might explain such an odd phenomenon yet, at the start of the twenty-first century ball lightning remains, as Arago said in 1854, "One of the most inexplicable problems of physics today."

Well, actually, ball lightning only poses problems to the physics of yesterday and today if it, you know, exists, and the evidence that it does is rather weak, as this book demonstrates. (Its author does come down in favour of the existence of ball lightning, and wrote the 1976 Nature paper which helped launched the modern study of the phenomenon.) As of the date this book was published, not a single unambiguous photograph, movie, or video recording of ball lightning was known to exist, and most of the "classic" photographs illustrated in chapter 9 are obvious fakes created by camera motion and double exposure. It is also difficult when dealing with reports by observers unacquainted with the relevant phenomena to sort out genuine ball lightning (if such exists) from other well-documented and understood effects such as corona discharges (St. Elmo's fire), that perennial favourite of UFO debunkers: ignis fatuus or swamp gas, and claims of damage caused by the passage of ball lightning or its explosive dissipation from those produced by conventional lightning strikes. See the author's re-casting of a lightning strike to a house which he personally investigated into "ball lightning language" on pp. 105-106 for an example of how such reports can originate.

Still, after sorting out the mis-identifications, hoaxes, and other dross, a body of reports remains, some by expert observers of atmospheric phenomena, which have a consistency not to be found, for example, in UFO reports. A number of observations of ball lightning within metallic aircraft fuselages are almost identical and pose a formidable challenge to most models. The absence of unambiguous evidence has not in any way deterred the theoretical enterprise, and chapters 11-13 survey models based on, among other mechanisms, heated air, self-confining plasma vortices and spheroids, radial charge separation, chemical reactions and combustion, microwave excitation of metastable molecules of atmospheric gases, nuclear fusion and the production of unstable isotopes of oxygen and nitrogen, focusing of cosmic rays, antimatter meteorites, and microscopic black holes. One does not get the sense of this converging upon a consensus. Among the dubious theories, there are some odd claims of experimental results such as the production of self-sustaining plasma balls by placing a short burning candle in a kitchen microwave oven (didn't work for me, anyway--if you must try it yourself, please use common sense and be careful), and reports of producing ball lightning sustained by fusion of deuterium in atmospheric water vapour by short circuiting a 200 tonne submarine accumulator battery. (Don't try this one at home, kids!)

The book concludes with the hope that with increasing interest in ball lightning, as evidenced by conferences such as the International Symposia on Ball Lightning, and additional effort in collecting and investigating reports, this centuries-old puzzle may be resolved within this decade. I'm not so sure--the UFO precedent does not incline one to optimism. For those motivated to pursue the matter further, a bibliography of more than 75 pages and 2400 citations is included.

Posted at June 12, 2005 16:36