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351. Geomagnetic Reversals From Impacts On The Earth

... Science Frontiers ONLINE No. 49: Jan-Feb 1987 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Geomagnetic Reversals From Impacts On The Earth R.A . Muller and D.E . Morris review the evidence tying geomagnetic reversals to the impacts of large bodies with the earth: the tektites and microtektites; the climate changes; the biological extinctions, etc. Then they propose a physical mechanism for geomagnetic reversals: "The impact of a large extraterrestrial object on the Earth can produce a geomagnetic reversal through the following mechanism: dust from the impact crater and soot from fires trigger a climate change and the beginning of a little ice age. The redistribution of water near the equator to ice at high latitudes alters the rotation rate of the crust and mantle of the Earth. If the sea-level change is sufficiently large ( 10 meters) and rapid (in a few hundred years), then the velocity shear in the liquid core disrupts the convective cells that drive the dynamo. The new convective cells that subsequently form distort and tangle the previous field, reducing the dipole component near to zero while increasing the energy in multipole components. Eventually a dipole is rebuilt by dynamo action, and the event is seen either as a geomagnetic reversal or as an excursion." (Muller, Richard A., and Morris, Donald E.; "Geomagnetic Reversals from Impacts on the Earth," Geophysical Research Letters, 13:1177, 1986.) Comment. That the earth's field is generated by internal dynamo action is ...

Terms matched: 1 - Score: 13 - 15 May 2017 - URL: /sf049/sf049p18.htm

352. Of Time and the Coral - and Other Things, Too

... the newly corrected radiocarbon scale has pushed the peak of the Ice Ages back from 18,000 BP to 21,000 BP. But there is more. The same article in Science, without saying how he came up with the number, has Bard fixing the strength of the earth's magnetic field at only half its present level 20,000 years ago. This is most interest-ing because over the last 400 years of direct measurements, the geomagnetic field has been steadily decreasing! When and why was there a peak in the intensity of the geomagnetic field? Back to Fairbanks, who also used his coral data to estimate changes in global sea level versus time. About 12,000 BP, he states, sea level was rising ten times faster than today due to melt water from the polar ice caps. This amounts to 2.5 to 4 meters per century. ". .. perhaps fast enough to prompt legends of a Great Flood"! (Kerr, Richard A.; "From One Coral Many Findings Blossom," Science, 248: 1314, 1990.) Comment. It is exceedingly rare to find a scientist musing that there really might have been a Flood. From Science Frontiers #71, SEP-OCT 1990 . 1990-2000 William R. Corliss ...

Terms matched: 1 - Score: 13 - 15 May 2017 - URL: /sf071/sf071g12.htm

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	Science Frontiers The Unusual & Unexplained Strange Science * Bizarre Biophysics * Anomalous astronomy From the pages of the World's Scientific Journals Archaeology Astronomy Biology Geology Geophysics Mathematics Psychology Physics

	About Science Frontiers Science Frontiers is the bimonthly newsletter providing digests of reports that describe scientific anomalies; that is, those observations and facts that challenge prevailing scientific paradigms. Over 2000 Science Frontiers digests have been published since 1976. These 2,000+ digests represent only the tip of the proverbial iceberg. The Sourcebook Project, which publishes Science Frontiers, also publishes the Catalog of Anomalies, which delves far more deeply into anomalistics and now extends to sixteen volumes, and covers dozens of disciplines. Over 14,000 volumes of science journals, including all issues of Nature and Science have been examined for reports on anomalies. In this context, the newsletter Science Frontiers is the appetizer and the Catalog of Anomalies is the main course. Subscriptions Subscriptions to the Science Frontiers newsletter are no longer available. Compilations of back issues can be found in Science Frontiers: The Book, and original and more detailed reports in the The Sourcebook Project series of books. The publisher Please note that the publisher has now closed, and can not be contacted.

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