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No. 95: Sep-Oct 1994

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Sylvanshine: a newly recognized optical phenomenon

Driving along a forested British Columbia road on a warm August night, A.B. Fraser noticed that some trees in the dark woods glowed spectacularly in the car's headlights -- almost as if they were covered with snow. Obviously snow was out of the question. Instead, the glow was some form of reflection from dew-covered leaves, and only from certain species of trees at that.

"Later nocturnal expeditions with a powerful flashlight (a proceeding that aroused dark suspicions in at least one local gamekeeper) showed that it favoured only certain types of conifer and a few shrubs such as the yew and rhododendron. The explanation lies in the contact angle of the droplets on the leaves: as this rises above 90 degrees or so, the proportion of light from the car's headlamps that is reflected back towards the occupant increases, and for angles above 140 degrees, the retroreflection becomes spectacular. Blue spruces show the glow particularly well."

(Matthews, Lindsay; "Reflections on a Summer's Night," Nature, 369:441, 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