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No. 35: Sep-Oct 1984

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Halley's comet is winking at us

Halley's Comet, still a billion kilometers away, is just beginning to emit gases at the urging of the sun's rays. It should, therefore, be getting brighter -- and it is -- but its brightness pulsates. A French team of scientists, led by Jean Lecacheux, has determined that Halley's Comet flares up at regular intervals just over 24 hours apart. We usually do not study comets carefully until they are very close to the sun, so we don't know if this blinking behavior is typical or not. The most reasonable explanation is that Halley's Comet rotates about every 24 hours and that its surface is not uniform. One portion of its surface may be brighter or emit more luminous gases than the rest. In any event, we have a new astronomical curiosity.

(Lloyd, Andrew; "Halley's Comet Is Blinking," New Scientist, p. 20, May 24, 1984.)

Reference. Cometary outbursts are cataloged at ACO20 in The Sun and Solar System Debris. This Catalog volume is described here.

From Science Frontiers #35, SEP-OCT 1984. 1984-2000 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