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No. 93: May-Jun 1994

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Anomalous Horizon Glows Seen On The Moon

The spacecraft Clementine, now engaged in surveying the moon from orbit, has apparently recorded once again a perplexing sky glow that precedes lunar sunrises and follows lunar sunsets. An astronaut standing on the moon watching the spot where the sun is about to rise would see first of all two well-recognized phenomena: the solar corona (even though the solar disc is still well below the horizon) and the zodiacal light (sunlight reflected from interplanetary dust). In addition, the astronaut would detect a glow along the horizon itself, as in the illustration. Since the moon is virtually airless, there should be none of those gas molecules and suspended dust particles that cause the sunsets and sunrises that we admire so much here on earth. Still, there must be something suspended above the moon's surface to scatter light from the sun still located just below the horizon. The best guess is that lunar dust particles are ionized by solar radiation and are repelled upwards from the surface and hang there suspended by electrostatic forces. But no one really knows for certain the cause of the glow.

(Cowen, R.; "On the Horizon: Clementine Probes Moon Glow," Science News, 145:197, 1994.)

Reference. Anomalous lunar horizon glows are cataloged in ALO11 in our catalog: The Moon and the Planets. For details, visit here.

From Science Frontiers #93, MAY-JUN 1994. 1994-2000 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