geomagnetic flip
... plates grew apart. This caused Europe and America to gradually drift apart from each other. As the tectonic plates are formed, their lava solidifies to basalt, causing the atoms to become magnetized. When the magnetic field reverses, the magnetizing effect causes the atoms aligning in the basalt to reverse. As scientists examine the patterns of magnetized basalt, they observed that the rock exhibited alternating alignments. This suggests there were times in the past when the poles were roughly interchanged. As does a tape recorder, the bottom of the ocean recorded the geomagnetic field. This recording contained a record of 50 million years of magnetic reversal. Tectonics is the science of the shaping of the Earth's crust; the process described as the moving of our planet’s crust is the essence of plate tectonics. Earth's crust consists of distinct plates that are continually rearranged. The entire motion is driven by the Earth's internal heat. After further research it was brought to attention of scientific community that the magnetic poles of the earth reverse on an average of about every 500,000 years. The last change was about 700,000 years ago. The evidence suggests we may be over due for a change. Experts worry that during magnetic reversals, the Earth would receive a higher dosage of high-energy ions and electrons called radiation. This might have an affect on living creatures on our planet. This is not so! Even today, the magnetic shield is not effective near the magnetic poles; moreover, radiation received on the ground is only slightly higher than anywhere else. The reason is, the magnetic field of the Earth is not our main shield against such particles. The atmosphere, equivalent to some 10 feet of concrete, serves as the planet’s protection. During the reversal, the magnetic field does not go away; it only gets weaker and develops several more magnetic poles at unpredictable locations. When the change occurs, it will be gradual. The field will not drop to an overall field strength of zero during this change. If the change in field strength were to drop to zero, it would mean that the magnetic energy of the Earth had been converted or dissipated. Right now, the main (dipole) field is getting weaker at a rate of about 7% per century. The energy of the field has hardly changed. What has happened is that the more complicated parts of the field (equivalent to several magnets in different directions) have gotten stronger while the main two-pole ("dipole") field has lost its strength. The polar field of the Sun seems to reverse about every eleven years. However, the Sun's magnetism is different; it has foci directly on its surface in the form of sunspots. Is the Earth's field getting weaker? The answer is yes and no. The magnetosphere is often viewed as being a two-pole ("dipole") structure similar to that of a small bar-magnet at the center of the Earth. Its inclination is approximately 11 degrees variant to the rotation axis of Earth. Therefore, the magnetic poles are not the same as the geographic ones. The magnetic charts note the mapping deviations between magnetic north and true north. The magnetic field is more complicated. It contains additional complex fields. The generated fields originate in the Earth's core, which is about half the radius of the planet. If we could go to the surface of the core, the strength of the magnetic field would be greater. The field weakens more rapidly with distance, so at the surface of the Earth, the field is quite weak. The magnetic field of the Earth changes all the time. Therefore, magnetic charts have to be redrawn from time to time. In the three hundred and sixty three years since the first careful mapping of the Earth's field, the dipole has become weaker by about 8% (the rate may have sped up in 1970). If one drew a straight line through the points, one would find that perhaps 1200 years from now, the line would spike through the zero point. It is possible that the magnetic field will go through a field-strength of zero...