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No. 56: Mar-Apr 1988

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Celestial mirages?

Those mysterious giant blue arcs mentioned above have at least two explanations. The less-favored states that the arcs are formed when a spherical light pulse from a briefly flaring quasar encounters a plane of gas and dust. This matter scatters the light, making it visible to us as a huge arc. The preferred model employs gravitational lensing. Here, the arcs are simply distorted images -- mirages, if you want -- of distant galaxies.

(Two of the many reports on this subject are: Waldrop, M. Mitchell; "The Giant Arcs Are Gravitational Mirages," Science, 238:1351, 1987; and Anonymous; "Giant Arcs: Light Echoes or Lensed Galaxies?" Sky and Telescope, 75:7, 1988.)

Comment. A bit of background: according to Einstein, the presence of matter can bend light rays, just as our atmosphere does when mirages are created by refraction. Gravitational mirages of celestial objects are thus predicted by Relativity.

From Science Frontiers #56, MAR-APR 1988. 1988-2000 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