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A pole shift theory is a hypothesis that the axis of rotation of a planet have not always been at their present-day locations or that they will not persist there; in other words, that its physical poles had been or will be shifted. Pole shift theory is almost always discussed in the context of Earth, but other solar system bodies may have experienced axial reorientation during their existences. Pole shift theories are not to be confused with plate tectonics, the well-accepted geological theory that the Earth's surface consists of solid plates which shift over a fluid asthenosphere; nor with continental drift, the corollary to plate tectonics which maintains that locations of the continents have moved slowly over the face of the earth, resulting in the gradual merging and breakup of continents and oceans over hundreds of millions of years.
Early proponents One early popular proponent of a pole shift theory was Hugh Auchincloss Brown, an electrical engineer who advanced a theory of catastrophic pole shift. Brown argued that accumulation of ice at the poles caused recurring tipping of the axis in cycles of approximately 7 millennia. Charles Hapgood is now perhaps the best remembered early proponent, from in his books The Earth's Shifting Crust (1958) (which includes a foreword by Albert Einstein) and Path of the Pole (1970). Hapgood speculated that the ice mass at one or both poles over-accumulates which destabilizes the earth's rotational balance, causing slippage of all or much of earth's outer crust around the earth's core, which retains its axial orientation. Based on his own research, he argued that each shift took approximately five thousand years, followed by 20 to 30 thousand year periods with no polar movements. Also, in his calculations, the area of movement never covered more than 40 degrees. His examples of recent locations for the North Pole include the Yukon Territory, Hudson Bay, and in the Atlantic Ocean between Iceland and Norway. This is an example of slow pole shift motion, which displays the most minor alterations and no destruction. A more dramatic view assumes more rapid changes, with dramatic alterations of geography and localized areas of destruction due to earthquakes and tsunamis. Several recent books propose changes that take place in weeks, days, or even hours, resulting in a variety of doomsday scenarios. Regardless of speed, the results of a shift occurring results in major climate changes for most of the earth's surface, as areas that were formally equatorial become temperate, and areas that were temperate become either more equatorial or more arctic. Hapgood wrote to Canadian librarian, Rand Flem-Ath, encouraging him in his pursuit of scientific evidence to back Hapgood's claim and in his expansion of the theory. Flem-Ath published the results of this work in 1995 in When the Sky Fell co-written with his wife, Rose. Other theories which are not dependent upon polar ice masses include those involving: New Age Theories The field has attracted many non-scientific authors, offering a wide variety of things as evidence, including such things as psychic readings. Theosophic writer David Pratt has put together a notable comparison of scientific views regarding pole shift compared to those of Theosophy. Recent Research Recent work by scientists and geologists Adam Maloof of Princeton University and Galen Halverson of Paul Sabatier University in Toulouse, France, says that Earth indeed rebalanced itself around 800 million years ago during the Precambrian time period. They tested this idea by studying magnetic minerals in sedimentary rocks in a Norwegian archipelago. Using these minerals, Maloof and Halverson found that the north pole shifted more than 50 degrees — about the current distance between Alaska and the equator — in less than 20 million years. This reasoning is supported by a record of changes in sea level and ocean chemistry in the Norwegian sediments that could be explained by true polar wander, the team reports in the September–October 2006 issue of the Geological Society of America Bulletin. Research using GPS, conducted by Geoffery Blewitt of the University of Nevada, has shown that normal seasonal changes in the distribution of ice and water causes minor movements of the poles. See also Notes | ||||||||
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