Why do the geomagnetic poles of the earth's north and south poles change every 50 million years?

Will the earth's magnetic poles reverse? Not long ago, some foreign media reported that experts believe that the two poles of the earth are currently in a reversal stage, but when it will happen is still uncertain. Once reversed, life on earth will be exposed to the solar wind with the ability to penetrate the ozone layer, and may even bring disaster to mankind. Once every half a million years? As early as the end of 16, william Gilbert, a British physicist, grinded a magnet into a sphere and tested the magnetic force distribution on the sphere with a small magnetic needle. As a result, he found that the inclination of the small magnetic needle was very similar to that measured on the ground at that time. From this, he asserted that the earth itself is a huge spherical magnet, and the magnetism of the earth emanates from the inside of the earth. In the past few years, the theory of reversal of the earth's magnetic field was one of the rumors of the theory of earth destruction. The so-called "geomagnetic reversal" is a mechanism within the earth, which makes the south pole change to the north pole and the north pole change to the south pole. In fact, scientists have long known that the earth's magnetic poles will drift and reverse. 183 1 year, when British scholars arrived at the north pole, they found that the north pole was separated from the magnetic north pole by a certain distance and set the position of the magnetic north pole. But in 1904, when Norwegian scholars re-measured the magnetic north pole, they found that it moved 50 kilometers from its original position. Now it is known that the magnetic north pole has been drifting at an accelerated rate of 100 years in the 20th century, with an average annual movement of about 10 km, and the magnetic fields at the two poles are also weakening. If this continues, the geomagnetic field will reverse. "Sooner or later, the earth's magnetic pole will reverse. Through previous observations, we can know that the earth's magnetic poles will have the phenomenon of north-south pole exchange, but this cycle is very long and can never be completed in a short time, so it is impossible to encounter such a thing in our lifetime. " Zhu Jin, director of the Beijing Planetarium, once said. Dr Andy Jackson, a geomagnetism expert at the University of Leeds in the United Kingdom, said that the earth's magnetic pole reversal usually happens every 500,000 years, but it has not happened for 750,000 years since the last time. In recent years, many geologists also believe that in the past 76 million years, the earth's magnetic pole has reversed at least 17 1 time, because many countries have found evidence of geomagnetic reversal from geological surveys. Li Jing, a researcher at the National Astronomical Observatory of the Chinese Academy of Sciences, also pointed out that during the10.6 billion years when dinosaurs existed, at least three times the North Pole turned into the South Pole and the South Pole turned into the North Pole, but it did not lead to devastating events such as biological extinction, at least it did not lead to the extinction of dinosaurs. The earth is a layered solid sphere, which is divided into crust, mantle, outer core and inner core. Humans live on the surface of the earth. "The existing drilling technology, even less than ten thousand meters underground. Human's scientific understanding and ability to the center of the earth are greatly limited, and there are still many unsolved mysteries inside the earth. " Xue Bingsen, a researcher at the National Space Weather Monitoring and Early Warning Center and the stationmaster of the space weather forecasting station, said that so far, scientists have not fully understood how the earth's magnetic field is generated, the reasons for its changes and the timetable for these changes. "Deep in the earth, an active lava core generates a magnetic field that can resist the destructive solar wind." This theory of the earth's magnetic field is an easily accepted hypothesis at present. Some foreign scientists say that in the past 200 years, the earth's magnetic field has weakened by 15%, which may be a sign that the earth's magnetic pole will reverse. Xue Bingsen pointed out that only in the last forty or fifty years have relevant instruments and equipment been able to accurately observe the changes of the earth's magnetic field. At present, the geomagnetic field intensity in some areas is indeed decreasing, but whether it means that the geomagnetic field intensity will continue to decrease and reverse in the next thousand years is still controversial in the scientific community. At present, there is no actual data to prove that the earth's magnetic field is collapsing or reversing. (According to Beijing Daily) Source: Invention and Innovation (Comprehensive Edition)