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No. 14: Winter 1981 Supplement

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Radial spokes in saturn's rings

Among all the recently discovered complexities of Saturn's rings, the dark spokes are perhaps the most challenging to astronomers. These dark areas seem to rotate with the rings and are likely regions nearly devoid of the particles that constitute the rings. The "normal" annular gaps between the rings can be explained in part as due to the gravitational influences of Saturn's moons. The dark spokes, however, do not succumb so easily. There are no obvious gravitational nuances that can sweep particles selectively from radially aligned areas.

(Anonymous; "Voyager Discovers Spokes in Saturn's Rings," New Scientist, 88: 276, 1980.)

Comment. Any theory accounting for radial gaps may also explain the "knots" of brightness occasionally seen through the telescope down the years. Incidentally, a few observers in the past have also claimed to have seen radial gaps in the rings, so the dark spokes are not exactly new.

Reference. Spoke phenomena of Saturn's rings are cataloged at ARL5 in The Moon and the Planets. A description of this book is located here.

From Science Frontiers #14, Winter 1981. 1981-2000 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