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No. 7: June 1979

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Post-eclipse brightening of io confirmed

For about 15 minutes after Jupiter's satellite Io emerges from the planet's shadow after an eclipse, it unaccountably brightens far beyond its normal level. Observing Io with a spectrophotometer in 1978, F.C. Witteborn et al measured a brightness increase in the 4.7-5.4 micron range that was three to five times the brightness at other phase angles. Long a controversial phenomenon, this confirmation of Io's post-eclipse brightening has led to a search for possible explanations. Witteborn et al suggest that the transient flare-up is a complex thermoluminescent effect excited by interaction with Jupiter's magnetosphere, followed by solar heating as Io emerges from the shadow.

(Witteborn, F.C. et al; "Io: An Intense Brightening near 5 Micrometers," Science, 203:643, 1979.)

Comment. Io also modulates Jupiter's microwave emissions.

From Science Frontiers #7, June 1979. 1979-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "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