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No. 36: Nov-Dec 1984

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The Magnetic Jerk Problem

We reported above that the earth's magnetic field "jerked" in 1969; that is, it suddenly accelerated its westward drift. The earth's core, which through dynamo action reputedly generates the magnetic field we detect at the surface, apparently does not keep pace with the outer crust. It is this sluggishness that produces the observed westward drift of the magnetic field of about 1 meter per hour. While most geophysicists acknowledge that something significant happened to the core in 1969, the geographical extent of the "jerk" is unclear. The acceleration of the field was clearcut in Europe but obscure or undetectable over much of North America. If the jerk was geographically limited, the core perturbation probably was, too. The earth's core may, in fact, eddy and swirl like the planet's atmosphere.

Going over past records, geophysicists think they have spotted another jerk in 1912; only that time the field decelerated.

(Kerr, Richard A.; "Magnetic 'Jerk" Gaining Wider Acceptance," Science, 225:1135, 1984.)

From Science Frontiers #36, NOV-DEC 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