In the period of 20 million years, the polarity has reversed. According to the law of nature, it occurs 200000-300000 years on average every year. However, the latest reversal delayed the future, with the last pole reversal occurring 780000 years ago. Although scientists are not sure, there are still some people who believe that the rotation of the magnetic pole is related to the convection in the outer core. Lighter components such as oxygen, sulfur and silicon will rise to the core mantle boundary. What accumulates is like sediments on the bottom of the sea, which “fall” from the nucleus to the mantle interface. When a large amount of sediment accumulates, it will roll out to the core like an avalanche and cool down. One inference is: “a large-scale core mantle boundary avalanche will destroy the earth’s generator and cause the collapse of the polar magnetic field.”
Scientists have learned from the magnetic properties of rocks and sediments that magnetic poles change positions periodically. Because this reversal will last 200000 years or more, change will last 1000 to 10000 years: it’s not a sudden reversal, it’s a slow process. In this process, the intensity of the magnetic field will weaken first, and then become more complex. Multiple magnetic poles will appear first, and after a period of time, the intensity of the magnetic field will recover, forming a linear shape in the opposite direction.
In the last few centuries, scientists think we are heading for another long-term reversal. Many people think that this process is very harmful to human beings and that the magnetosphere will hardly disappear. Therefore, in the process of reversal, life on earth will still be protected. But if the magnetic field weakens significantly, we’re in trouble. In fact, some researchers believe that “the demise of the Neanderthals was directly related to the weakening of the magnetic field during the same period.”
In recent years, scientists have evidence that pole reversal may occur soon, but it is not clear whether it can complete the pole reversal. In the late 1960s, near the village of La champ in the central French plateau, scientists found some incomplete evidence that the Neanderthals disappeared from Europe 41 000 years ago, and there was a very fast short-term magnetic pole reversal.
Another evidence of rapid reversal was found in 1995 in the solidified magma of the Steens mountains, Oregon. There, magnetic crystals in the rocks show a very fast pole shift, moving at a speed of “six degrees a day, ten thousand times the usual speed.”.
At this rate, a complete pole shift will take months, not tens of thousands of years. So it wasn’t until 2010, when scientists found more evidence that the magnetic field moved 53 degrees in a year, that people began to doubt it. In 2012, scientists discovered the lazanne event again, that is, in the process of detecting sediments in the Black Sea, South Pacific, North Atlantic and other waters. They have amazing performances:
This geometric reversal of the poles of the magnetic field, that is, the lines of force pointing in the opposite direction to today, occurred 440 years ago, when the intensity of the magnetic field was only a quarter of what it is today. And the magnetic field of this process is weaker, only 5% of today’s. As a result, the earth’s resistance to cosmic rays is almost lost, and it is exposed to super intense radiation.
Although there is no direct causal relationship, the core of Black Sea sediments also indicates that there are two other extreme events in the same period: many abrupt climate changes occurred in the last glacial period, accompanied by the volcanic eruption in the northern hemisphere with a ten thousand year return period, and the rapid reversal of the earth’s magnetic field near Naples, Italy.