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No. 95: Sep-Oct 1994

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Gamma-ray flashes in the upper atmosphere

Something strange is definitely going on in the upper atmosphere, particularly above thunderstorms. We have already reported on the mysterious light flashes (SF90) and radio emissions (SF#94). Now, we record similar, possibly intimately related flashes of energy in a different portion of the electromagnetic spectrum.

"Detectors aboard the Compton Gamma Ray Observatory have observed an unexplained terrestrial phenomenon: brief, intense flashes of gamma rays. These flashes must originate in the atmosphere at altitudes above at least 30 kilometers in order to escape atmospheric absorption and reach the detectors."

The energies of the gamma rays in the flashes are very high. They are typical of the braking radiation (Bremsstrahlung) from 1,000,000 electron-volt electrons. Since most of the gamma flashes originate over regions where thunderstorms are frequent, it is tempting to associate them with lightning. Ordinary lightning, however, is not energetic enough to generate the gamma flashes and, of course, it does not occur above 30 kilometers altitude anyway. G.J. Fishman et al, who reported on this new phenomenon in Science, speculate that some hitherto unrecognized, high altitude electrical discharges occur high above areas hosting thunderstorms. Possibly, upwardly directed lightning ("rocket lightning") is involved in all three of the newly found flashes in the radio, optical, and gamma portions of the electromagnetic spectrum.

(Fishman, G.J., et al; "Discovery of Intense Gamma-Ray Flashes of Atmospheric Origin," Science, 264:1313, 1994. Kerr, Richard A.; "Atmospheric Scientists Puzzle Over High-Altitude Flashes," Science, 264:1250, 1994.)

From Science Frontiers #95, SEP-OCT 1994. 1994-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:

Quotes

  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987