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No. 54: Nov-Dec 1987

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The changing magnetic climate: does it affect civilizations?

Abstract. "Past values for the geomagnetic intensity may be obtained by laboratory analysis of the thermoremanent magnetization carried by clay baked in ancient times. From global averages of such determinations it is commonly accepted that the intensity in any given region went through a broad maximum about 2000 years ago, reaching a level about 50% higher than at present. Here we present results obtained from a wide range of Chinese pottery, spanning the interval from 4000 BC to the present, indicating that the field behaviour was more complex. The intensity was high between 1500 and 1000 BC and again in the first half of the first millennium AD. Comparison with results reported for Western Asia, Egypt and Crete suggests that these high values are due to non-dipole disturbances in the geomagnetic field, consistent with long-term records of the cosmogenic radioisotopes 14C and 10Be."

(Quing-Yun, Wei, et al; "Geomagnetic Intensity as Evaluated from Ancient Chinese Pottery," Nature, 328:330, 1987.)

Comment. This article stimulates three questions:

  1. What caused the geomagnetic changes; could some be of internal origin?

  2. Are periods of reduced magnetic fields associated with cultural changes? The graph, for example, reveals a dip during the flowering of Greek civilization.

  3. Could such ambient magnetic changes have an effect on human imagination, as reported in laboratory test?. See SF#53.

Ratios of ancient geomagnetic field intensity versus date Ratios of ancient geomagnetic field intensity to present intensity versus date. Data from China.

From Science Frontiers #54, NOV-DEC 1987. 1987-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:

Quotes

  • "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