When I was growing up in the 1950s people talked a lot about the polar shift. As a child I thought the whole planet flipped but since then that isn't what happens. Instead what happens every 250,000 years to 750,000 years here on earth is the magnetic north moves slowly to another location and the south magnetic South moves to a different location as well. During this 1000 year or more process the magnetic fields (which protect us from mutation and cosmic rays) reduce to around 0% to 10% of normal which we had before the year 2000.
Also, Magnetic north is moving from Canada where it was when I was growing up to Siberia where it is now moving over 40 miles per year in that direction.
The least Scary of the two major kinds is: geomagnetic excursions. So, most people hope we are on a geomagnetic excursion rather than a Geomagnetic reversal which is a completely pole shift. However, even if we are on a geomagnetic excursion there will be genetic mutations because the magnetic fields which protect us from Cosmic Rays won't be there enough to protect all earth living on the surface of earth or above like Humans, animals and birds from genetic mutation.
geomagnetic reversal
Geomagnetic reversal
From Wikipedia, the free encyclopedia
"Magnetic reversal" redirects here. For switching of a magnet, see Magnetization reversal.
"Polarity reversal" redirects here. For a seismic anomaly, see Polarity reversal (seismology).
Geomagnetic polarity during the last 5 million years (Pliocene and Quaternary, late Cenozoic Era).
Dark areas denote periods where the polarity matches today's polarity,
light areas denote periods where that polarity is reversed.
Contents
History
In the early 20th century, geologists first noticed that some volcanic rocks were magnetized opposite to the direction of the local Earth's field. The first estimate of the timing of magnetic reversals was made by Motonori Matuyama in the 1920s; he observed that rocks with reversed fields were all of early Pleistocene age or older. At the time, the Earth's polarity was poorly understood, and the possibility of reversal aroused little interest.[2][3]Three decades later, when Earth's magnetic field was better understood, theories were advanced suggesting that the Earth's field might have reversed in the remote past. Most paleomagnetic research in the late 1950s included an examination of the wandering of the poles and continental drift. Although it was discovered that some rocks would reverse their magnetic field while cooling, it became apparent that most magnetized volcanic rocks preserved traces of the Earth's magnetic field at the time the rocks had cooled. In the absence of reliable methods for obtaining absolute ages for rocks, it was thought that reversals occurred approximately every million years.[2][3]
The next major advance in understanding reversals came when techniques for radiometric dating were developed in the 1950s. Allan Cox and Richard Doell, at the United States Geological Survey, wanted to know whether reversals occurred at regular intervals, and invited the geochronologist Brent Dalrymple to join their group. They produced the first magnetic-polarity time scale in 1959. As they accumulated data, they continued to refine this scale in competition with Don Tarling and Ian McDougall at the Australian National University. A group led by Neil Opdyke at the Lamont-Doherty Geological Observatory showed that the same pattern of reversals was recorded in sediments from deep-sea cores.[3]
During the 1950s and 1960s information about variations in the Earth's magnetic field was gathered largely by means of research vessels. But the complex routes of ocean cruises rendered the association of navigational data with magnetometer readings difficult. Only when data were plotted on a map did it become apparent that remarkably regular and continuous magnetic stripes appeared on the ocean floors.[2][3]
In 1963, Frederick Vine and Drummond Matthews provided a simple explanation by combining the seafloor spreading theory of Harry Hess with the known time scale of reversals: if new sea floor is magnetized in the direction of the field, then it will change its polarity when the field reverses. Thus, sea floor spreading from a central ridge will produce magnetic stripes parallel to the ridge.[4] Canadian L. W. Morley independently proposed a similar explanation in January 1963, but his work was rejected by the scientific journals Nature and Journal of Geophysical Research, and remained unpublished until 1967, when it appeared in the literary magazine Saturday Review.[2] The Morley–Vine–Matthews hypothesis was the first key scientific test of the seafloor spreading theory of continental drift.[3]
Beginning in 1966, Lamont–Doherty Geological Observatory scientists found that the magnetic profiles across the Pacific-Antarctic Ridge were symmetrical and matched the pattern in the north Atlantic's Reykjanes ridges. The same magnetic anomalies were found over most of the world's oceans, which permitted estimates for when most of the oceanic crust had developed.[2][3]
Observing past fields
Geomagnetic polarity since the middle Jurassic.
Dark areas denote periods where the polarity matches today's polarity,
light areas denote periods where that polarity is reversed.
The past record of geomagnetic reversals was first noticed by observing the magnetic stripe "anomalies" on the ocean floor. Lawrence W. Morley, Frederick John Vine and Drummond Hoyle Matthews made the connection to seafloor spreading in the Morley-Vine-Matthews hypothesis[4][5] which soon led to the development of the theory of plate tectonics. The relatively constant rate at which the sea floor spreads results in substrate "stripes" from which past magnetic field polarity can be inferred from data gathered from towing a magnetometer along the sea floor.
Because no existing unsubducted sea floor (or sea floor thrust onto continental plates) is more than about 180 million years (Ma) old, other methods are necessary for detecting older reversals. Most sedimentary rocks incorporate tiny amounts of iron rich minerals, whose orientation is influenced by the ambient magnetic field at the time at which they formed. These rocks can preserve a record of the field if it is not later erased by chemical, physical or biological change.
Because the magnetic field is global, similar patterns of magnetic variations at different sites may be used to correlate age in different locations. In the past four decades much paleomagnetic data about seafloor ages (up to ~250 Ma) has been collected and is useful in estimating the age of geologic sections. Not an independent dating method, it depends on "absolute" age dating methods like radioisotopic systems to derive numeric ages. It has become especially useful to metamorphic and igneous geologists where index fossils are seldom available.
Geomagnetic polarity time scale
Further information: Magnetostratigraphy
Through analysis of seafloor magnetic anomalies and dating of
reversal sequences on land, paleomagnetists have been developing a Geomagnetic Polarity Time Scale (GPTS). The current time scale contains 184 polarity intervals in the last 83 million years.[6][7]Changing frequency over time
The rate of reversals in the Earth's magnetic field has varied widely over time. 72 million years ago (Ma), the field reversed 5 times in a million years. In a 4-million-year period centered on 54 Ma, there were 10 reversals; at around 42 Ma, 17 reversals took place in the span of 3 million years. In a period of 3 million years centering on 24 Ma, 13 reversals occurred. No fewer than 51 reversals occurred in a 12-million-year period, centering on 15 million years ago. Two reversals occurred during a span of 50,000 years. These eras of frequent reversals have been counterbalanced by a few "superchrons" – long periods when no reversals took place.[8]Superchrons
A superchron is a polarity interval lasting at least 10 million years. There are two well-established superchrons, the Cretaceous Normal and the Kiaman. A third candidate, the Moyero, is more controversial. The Jurassic Quiet Zone in ocean magnetic anomalies was once thought to represent a superchron, but is now attributed to other causes.The Cretaceous Normal (also called the Cretaceous Superchron or C34) lasted for almost 40 million years, from about 120 to 83 million years ago, including stages of the Cretaceous period from the Aptian through the Santonian. The frequency of magnetic reversals steadily decreased prior to the period, reaching its low point (no reversals) during the period. Between the Cretaceous Normal and the present, the frequency has generally increased slowly.[9]
The Kiaman Reverse Superchron lasted from approximately the late Carboniferous to the late Permian, or for more than 50 million years, from around 312 to 262 million years ago.[9] The magnetic field had reversed polarity. The name "Kiaman" derives from the Australian village of Kiama, where some of the first geological evidence of the superchron was found in 1925.[10]
The Ordovician is suspected to host another superchron, called the Moyero Reverse Superchron, lasting more than 20 million years (485 to 463 million years ago). But until now this possible superchron has only been found in the Moyero river section north of the polar circle in Siberia.[11] Moreover, the best data from elsewhere in the world do not show evidence for this superchron.[12]
Certain regions of ocean floor, older than 160 Ma, have low-amplitude magnetic anomalies that are hard to interpret. They are found off the east coast of North America, the northwest coast of Africa, and the western Pacific. They were once thought to represent a superchron called the Jurassic Quiet Zone, but magnetic anomalies are found on land during this period. The geomagnetic field is known to have low intensity between about 130 Ma and 170 Ma, and these sections of ocean floor are especially deep, so the signal is attenuated between the floor and the surface.[12]
Statistical properties of reversals
Several studies have analyzed the statistical properties of reversals in the hope of learning something about their underlying mechanism. The discriminating power of statistical tests is limited by the small number of polarity intervals. Nevertheless, some general features are well established. In particular, the pattern of reversals is random. There is no correlation between the lengths of polarity intervals.[13] There is no preference for either normal or reversed polarity, and no statistical difference between the distributions of these polarities. This lack of bias is also a robust prediction of dynamo theory.[9] Finally, as mentioned above, the rate of reversals changes over time.The randomness of the reversals is inconsistent with periodicity, but several authors have claimed to find periodicity.[14] However, these results are probably artifacts of an analysis using sliding windows to determine reversal rates.[15]
Most statistical models of reversals have analyzed them in terms of a Poisson process or other kinds of renewal process. A Poisson process would have, on average, a constant reversal rate, so it is common to use a non-stationary Poisson process. However, compared to a Poisson process, there is a reduced probability of reversal for tens of thousands of years after a reversal. This could be due to an inhibition in the underlying mechanism, or it could just mean that some shorter polarity intervals have been missed.[9] A random reversal pattern with inhibition can be represented by a gamma process. In 2006, a team of physicists at the University of Calabria found that the reversals also conform to a Lévy distribution, which describes stochastic processes with long-ranging correlations between events in time.[16][17] The data are also consistent with a deterministic, but chaotic, process.[18]
Character of transitions
Duration
Most estimates for the duration of a polarity transition are between 1,000 and 10,000 years.[9] However, studies of 15-million-year-old lava flows on Steens Mountain, Oregon, indicate that the Earth's magnetic field is capable of shifting at a rate of up to 6 degrees per day.[19] This was initially met with skepticism from paleomagnetists. Even if changes occur that quickly in the core, the mantle, which is a semiconductor, is thought to act as a low-pass filter, removing variations with periods less than a few months. A variety of possible rock magnetic mechanisms were proposed that would lead to a false signal.[20] However, paleomagnetic studies of other sections from the same region (the Oregon Plateau flood basalts) give consistent results.[21][22] It appears that the reversed-to-normal polarity transition that marks the end of Chron C5Cr (16.7 million years ago) contains a series of reversals and excursions.[23] In addition, geologists Scott Bogue of Occidental College and Jonathan Glen of the US Geological Survey, sampling lava flows in Battle Mountain, Nevada, found evidence for a brief, several-year-long interval during a reversal when the field direction changed by over 50 degrees. The reversal was dated to approximately 15 million years ago.[24][25]Magnetic field
The magnetic field will not vanish completely, but many poles might form chaotically in different places during reversal, until it stabilizes again.[26][27]Causes
NASA computer simulation using the model of Glatzmaier and Roberts.[28] The tubes represent magnetic field lines,
blue when the field points towards the center and yellow when away. The
rotation axis of the Earth is centered and vertical. The dense clusters
of lines are within the Earth's core.[27]
In some simulations, this leads to an instability in which the magnetic field spontaneously flips over into the opposite orientation. This scenario is supported by observations of the solar magnetic field, which undergoes spontaneous reversals every 9–12 years. However, with the Sun it is observed that the solar magnetic intensity greatly increases during a reversal, whereas reversals on Earth seem to occur during periods of low field strength.[31]
Hypothesized triggers
Some scientists, such as Richard A. Muller, think that geomagnetic reversals are not spontaneous processes but rather are triggered by external events that directly disrupt the flow in the Earth's core. Proposals include impact events[32][33] or internal events such as the arrival of continental slabs carried down into the mantle by the action of plate tectonics at subduction zones or the initiation of new mantle plumes from the core-mantle boundary.[34] Supporters of this hypothesis hold that any of these events could lead to a large scale disruption of the dynamo, effectively turning off the geomagnetic field. Because the magnetic field is stable in either the present North-South orientation or a reversed orientation, they propose that when the field recovers from such a disruption it spontaneously chooses one state or the other, such that half the recoveries become reversals. However, the proposed mechanism does not appear to work in a quantitative model, and the evidence from stratigraphy for a correlation between reversals and impact events is weak. Most strikingly, there is no evidence for a reversal connected with the impact event that caused the Cretaceous–Paleogene extinction event.[35]Effects on biosphere
Shortly after the first geomagnetic polarity time scales were produced, scientists began exploring the possibility that reversals could be linked to extinctions. Most such proposals rest on the assumption that the Earth's magnetic field would be much weaker during reversals. Possibly the first such hypothesis was that high energy particles trapped in the Van Allen radiation belt could be liberated and bombard the Earth.[36][37] Detailed calculations confirm that, if the Earth's dipole field disappeared entirely (leaving the quadrupole and higher components), most of the atmosphere would become accessible to high energy particles, but would act as a barrier to them, and cosmic ray collisions would produce secondary radiation of beryllium-10 or chlorine-36. An increase of beryllium-10 was noted in a 2012 German study showing a peak of beryllium-10 in Greenland ice cores during a brief complete reversal 41,000 years ago which led to the magnetic field strength dropping to an estimated 5% of normal during the reversal.[1] There is evidence that this occurs both during secular variation[38][39] and during reversals.[40][41]Another hypothesis by McCormac and Evans assumes that the Earth's field would disappear entirely during reversals.[42] They argue that the atmosphere of Mars may have been eroded away by the solar wind because it had no magnetic field to protect it. They predict that ions would be stripped away from Earth's atmosphere above 100 km. However, the evidence from paleointensity measurements is that the magnetic field does not disappear. Based on paleointensity data for the last 800,000 years,[43] the magnetopause is still estimated to be at about 3 Earth radii during the Brunhes-Matuyama reversal.[36] Even if the magnetic field disappeared, the solar wind may induce a sufficient magnetic field in the Earth's ionosphere to shield the surface from energetic particles.[44]
Hypotheses have also been advanced linking reversals to mass extinctions.[45] Many such arguments were based on an apparent periodicity in the rate of reversals; more careful analyses show that the reversal record is not periodic.[15] It may be, however, that the ends of superchrons have caused vigorous convection leading to widespread volcanism, and that the subsequent airborne ash caused extinctions.[46]
Tests of correlations between extinctions and reversals are difficult for a number of reasons. Larger animals are too scarce in the fossil record for good statistics, so paleontologists have analyzed microfossil extinctions. Even microfossil data can be unreliable if there are hiatuses in the fossil record. It can appear that the extinction occurs at the end of a polarity interval when the rest of that polarity interval was simply eroded away.[20] Statistical analysis shows no evidence for a correlation between reversals and extinctions.[47][36]
See also
References
- Plotnick, Roy E. (1 January 1980). "Relationship between biological extinctions and geomagnetic reversals". Geology 8 (12): 578. Bibcode:1980Geo.....8..578P. doi:10.1130/0091-7613(1980)8<578:rbbeag>2.0.CO;2.
Further reading
- Behrendt, J.C., Finn, C., Morse, L., Blankenship, D.D. "One hundred negative magnetic anomalies over the West Antarctic Ice Sheet (WAIS), in particular Mt. Resnik, a subaerially erupted volcanic peak, indicate eruption through at least one field reversal" University of Colorado, U.S. Geological Survey, University of Texas. (U.S. Geological Survey and The National Academies); USGS OF-2007-1047, Extended Abstract 030. 2007.
- Okada, M., Niitsuma, N., "Detailed paleomagnetic records during the Brunhes-Matuyama geomagnetic reversal, and a direct determination of depth lag for magnetization in marine sediments" Physics of the Earth and Planetary Interiors, Volume 56, Issue 1-2, p. 133-150. 1989.
External links
|title= (help)end quote from:
geomagnetic reversal
Pole shift hypothesis - Wikipedia, the free...
en.wikipedia.org/wiki/Pole_shift_hypothesisCachedThis article is about the hypothesis of pole shift in its historical context. For a description of the modern scientific understanding, see true polar wander.Pole shift hypothesis
From Wikipedia, the free encyclopedia"Polar Shift" redirects here. For the Clive Cussler novel, see Polar Shift (novel). For the Antarctica benefit compilation, see Polar Shift (album).This article is about the hypothesis of pole shift in its historical context. For a description of the modern scientific understanding, see true polar wander.For magnetic poles, see Geomagnetic reversal.The cataclysmic pole shift hypothesis suggests that there have been geologically rapid shifts in the relative positions of the modern-day geographic locations of the poles and the axis of rotation of the Earth, creating calamities such as floods and tectonic events.[1]
There is evidence of precession and changes in axial tilt, but this change is on much longer time-scales and does not involve relative motion of the spin axis with respect to the planet. However, in what is known as true polar wander, the solid Earth can rotate with respect to a fixed spin axis. Research shows that during the last 200 million years a total true polar wander of some 30° has occurred, but that no super-rapid shifts in the Earth's pole were found during this period.[2] A characteristic rate of true polar wander is 1° or less per million years.[3] Between approximately 790 and 810 million years ago, when the supercontinent Rodinia existed, two geologically rapid phases of true polar wander may have occurred. In each of these, the magnetic poles of the Earth shifted by ~55°.[4]
Contents
Definition and clarification
From 1982 to 2005, the pole drifted southeast toward northern Labrador, Canada, at a rate of about 2 milliarcseconds —or roughly 6 centimetres — per year. But in 2005, the pole changed course and began galloping east toward Greenland at a rate of more than 7 milliarcseconds per year.[citation needed] The geographic poles of the Earth are the points on the surface of the planet that are intersected by the axis of rotation. The pole shift hypothesis describes a change in location of these poles with respect to the underlying surface – a phenomenon distinct from the changes in axial orientation with respect to the plane of the ecliptic that are caused by precession and nutation, and is an amplified event of a true polar wander.
Pole shift hypotheses are not connected with plate tectonics, the well-accepted geological theory that the Earth's surface consists of solid plates which shift over a viscous, or semifluid 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,[5] resulting in the gradual emerging and breakup of continents and oceans over hundreds of millions of years.[6]
Pole shift hypotheses are not the same as geomagnetic reversal, the periodic reversal of the Earth's magnetic field (effectively switching the north and south magnetic poles).
Speculative history
In popular literature, many conjectures have been suggested involving very rapid polar shift. A slow shift in the poles would display 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.
Early proponents
An early mention of a shifting of the Earth's axis can be found in an 1872 article entitled "Chronologie historique des Mexicains"[7] by Charles Étienne Brasseur de Bourbourg, a specialist in Mesoamerican codices who interpreted ancient Mexican myths as evidence for four periods of global cataclysms that had begun around 10,500 BCE. In 1948, Hugh Auchincloss Brown, an electrical engineer, advanced a hypothesis of catastrophic pole shift. Brown also argued that accumulation of ice at the poles caused recurring tipping of the axis, identifying cycles of approximately seven millennia.[8][9]
In his controversial 1950 work Worlds in Collision, Immanuel Velikovsky postulated that the planet Venus emerged from Jupiter as a comet. During two proposed near approaches in about 1,450 BCE, he suggested that the direction of the Earth's rotation was changed radically, then reverted to its original direction on the next pass. This disruption supposedly caused earthquakes, tsunamis, and the parting of the Red Sea. Further, he said near misses by Mars between 776 and 687 BCE also caused the Earth's axis to change back and forth by ten degrees. Velikovsky included in his work references to historical records. His reading of the historical records has been disregarded, and his scientific arguments have been disproven.[10]
Charles Hapgood is now perhaps the best remembered early proponent. In his books The Earth's Shifting Crust (1958) (which includes a foreword by Albert Einstein)[11][12] and Path of the Pole (1970), Hapgood, building on Adhemar's much earlier model,[citation needed] speculated that the ice mass at one or both poles over-accumulates and 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, Hapgood argued that each shift took approximately 5,000 years, followed by 20,000- to 30,000-year periods with no polar movements. Also, in his calculations, the area of movement never covered more than 40 degrees. Hapgood's examples of recent locations for the North Pole include Hudson Bay (60˚N, 73˚W), the Atlantic Ocean between Iceland and Norway (72˚N, 10˚E) and Yukon (63˚N, 135˚W). However, in his subsequent work The Path of the Pole, Hapgood conceded Einstein's point that the weight of the polar ice would be insufficient to bring about a polar shift. Instead, Hapgood argued that the forces that caused the shifts in the crust must be located below the surface.[13] Hapgood wrote to a Canadian librarian, Rand Flem-Ath, encouraging him in his pursuit of scientific evidence to back Hapgood's claims and in his expansion of the hypothesis. Flem-Ath published the results of this work in 1995 in When the Sky Fell co-written with his wife.[14]
In 1974 Flavio Barbiero, an engineer and explorer, theorized that shifting of the Earth's axis took place 11,000 years ago and caused what was subsequently recorded in myth as the destruction of Atlantis and Mu. He suggested that shifting was probably caused by the impact of a comet on the Earth's surface and that the current position of Atlantis has to be sought under the Antarctic ice sheet.[15]
Recent conjectures
The field has attracted a number of authors offering a variety of evidence.
In the 1970s and 1980s a series of books not intended as fiction by former Washington newspaper reporter Ruth Shick Montgomery elaborates on Edgar Cayce readings.[16]
In 1997 Richard W. Noone published 5/5/2000, ICE: The Ultimate Disaster. This book argued that a cataclysmic shift of the Earth's ice cap covering Antarctica caused by a planetary alignment and solar storms, would lead to crustal displacement on May 5, 2000.[17]
In 1998 retired civil engineer James G. Bowles proposed in Atlantis Rising magazine a mechanism by which a polar shift could occur. He named this Rotational-Bending, or the RB-effect. He hypothesized that combined gravitational effects of the Sun and the Moon pulled at the Earth's crust at an oblique angle. This force steadily wore away at the underpinnings that linked the crust to the inner mantle. This generates a plastic zone that allows the crust to rotate with respect to the lower layers. Centrifugal forces would act on the mass of ice at the poles, causing them to move to the equator.[18]
Books on this subject have been published by William Hutton, including the 1996 book Coming Earth Changes: Causes and Consequences of the Approaching Pole Shift (ISBN 0876043619), which compared geologic records with the psychic readings of Edgar Cayce and predicted catastrophic climate changes before the end of 2001. In 2004 Hutton and co-author Jonathan Eagle published Earth's Catastrophic Past and Future: A Scientific Analysis of Information Channeled by Edgar Cayce (ISBN 1-58112-517-8), which summarizes possible mechanisms and the timing of a future pole shift.
Scientific research
Main article: True polar wanderWhile there are reputable studies showing that true polar wander has occurred at various times in the past, the rates are much smaller (1° per million years or slower) than predicted by the pole shift hypothesis (up to 1° per thousand years).[2][3][19] Analysis of the evidence does not lend credence to Hapgood's hypothesized rapid displacement of layers of the Earth.[20] Data indicate that the geographical poles have not deviated by more than about 5° over the last 130 million years, contradicting the hypothesis of a cataclysmic polar wander event.[21] More rapid past possible occurrences of true polar wander have been measured: from 790 to 810 million years ago, true polar wander of approximately 55° may have occurred twice.[4] There is no physical evidence of more rapid shifts occurring at any point during Earth's history.
See also
- Doomsday event
- Earth Changes
- Geomagnetic reversal
- North Magnetic Pole
- South Magnetic Pole
- Tollmann's hypothetical bolide
Notes
- Kiger, Patrick J. Ends of the Earth: Shifting of the Poles. National Geographic. Retrieved 2009-11-22.
- Tarduno, John A.; Smirnova, Alexei V. (January 15, 2001). "Stability of the Earth with respect to the spin axis for the last 130 million years". Earth and Planetary Science Letters 184 (2): 549–553. Bibcode:2001E&PSL.184..549T. doi:10.1016/S0012-821X(00)00348-4.
External links
- Alleged “Evidence” of Earth Crustal Displacement (Pole Shift) Analysis of specific evidence used to argue for geologically recent Pole Shift
- Fingerprints of the Gods (1995) by Graham Hancock, an analysis of arguments made for a Late Pleistocene Pole Shift, based on the ideas of Rand Flem-Ath by Heinrich, Paul V. "The Wild Side of Geoarchaeology Page". Archived from the original on 2011-05-25. Retrieved 28 July 2013.
- “The Day the Earth Fell Over” at LiveScience
- Charting Imaginary Worlds: Pole Shifts, Ice Sheets, and Ancient Sea Kings
- Minds in Ablation Part Five Addendum: Living in Imaginary Worlds More about interpreting ancient maps and ideas of Charles Hapgood.
- The Kerplop! Theory: Acme Instant Ice-Sheet Kit (Some Assembly Required)
- A Corruption of European History - Buache's Map of 1739, About.com European History
- Mason, Betsy (30 August 2006). "Earth's Poles May Have Wandered". ScienceNOW. Archived from the original on 2013-01-17.
- “What is that pole shift thing?", Daily Common Sense blog
- end quote from:
Pole shift hypothesis - Wikipedia, the free...
No comments:
Post a Comment