What happens when the earth's magnetic poles are reversed

Magnetic pole reversal

     This entry is reviewed by the "Science China" Science Encyclopedia entry compilation and application work project.

No matter where the magnetic needle is on the earth, its two ends always point to the north and south directions respectively, indicating that the earth is a huge magnetic field. However, the earth’s magnetic field is not immutable. Its north and south magnetic poles have changed positions. That is, the north pole of the geomagnetism changes into the south pole of the geomagnetism, and the south pole of the geomagnetism becomes the north pole of the geomagnetism.

Principle conjecture

      There are two kinds of conjectures: accidental phenomena and inevitable phenomena. Except for the inner core of the earth, which is solid (caused by high pressure), the rest is liquid, which is liquid iron. Since the above-mentioned conjecture generated by the magnetic field is that "the circulating flow of molten iron produces electromagnetism", then some convection may suddenly cause a loop, the loop is derived to the ground to produce an anti-loop, and finally the entire magnetic field is reversed. The entire process lasts from 30,000 to 1 million years. The geomagnetic field is first completely chaotic, then fades in about 10,000 years, and then strengthens in the opposite direction. Some people think that this problem can be solved within a few thousand years. However, some people think it is inevitable, it is regular and predictable, but it has not been grasped by human beings. American scientists studied the sedimentary rocks at the bottom of Lake Minnesota and showed that the earth has not changed its magnetic poles for 700,000 years, but in the past 4,000 years, the magnetic field has been rapidly weakened, losing half its strength. It can be seen that the earth has entered the eve of the reversal of the magnetic field.

Consequences

    If the magnetic poles are reversed... Let's first understand the solar wind. The solar wind is the huge energy that the sun transmits in the form of charged particles at a high speed, reaching hundreds of kilometers per second. The huge space between planets in the solar system is dominated by the solar wind.

If the magnetic poles are reversed... there will be a period of time when the earth has no magnetic field at all. The "Earth Flip" that everyone is worried about will not happen, but just "no magnetic field" is scary enough.

1) Low-latitude artificial satellites will be destroyed by the solar wind. Human communication is paralyzed.

2) Due to the loss of biological orientation, leading to mass extinction of organisms.

3) Because the earth loses the protection of the geomagnetic field, the ozone layer cannot be attached to the surface of the earth under the action of the geomagnetic field, so that the earth without the protection of the ozone layer is exposed to cosmic rays and solar particle radiation, which will have a fatal impact on the earth's climate and human life . Some scientists even believe that the existence of ancient human civilization was destroyed due to the inversion of the magnetic poles.

However, scientists are not yet pessimistic. They are monitoring on the one hand, and researching on the other. It is hoped that in the future, an instrument to control the earth's magnetic field can be developed. The earth is our home, and we can’t give it up casually.

Reversal period

     Earth’s magnetic pole reversal took 7,000 years

     Clement, a geologist at Florida International University in the United States, discovered through research that the time required for the reversal of the earth's magnetic field is about 7,000 years, and the time for magnetic reversal in low latitudes is shorter than that in high latitudes.

Clement said that in the history of geology, the earth's magnetic field often changed drastically from time to time, and the magnetic field lines would completely change the direction. This kind of magnetic pole conversion provides important clues for understanding the formation process of the magnetic field. In the past few years, the International Ocean Drilling Program funded by the National Science Foundation has enabled scientists to find new magnetic pole reversal "records" from the natural world, and it is possible to determine the important characteristics of this reversal.

Clement pointed out that the scientific community generally believes that during the reversal of the magnetic poles, the earth’s magnetic field is weakened to about 10% of all magnetism, the direction of the magnetic field changes nearly 180 degrees, and the magnetism is then strengthened again in the reversed direction. But how long this process will take has been uncertain, and scientists can only answer vaguely "thousands of years."

Through the study of deep-sea sedimentary cores, Clement found that the average time required for the reversal of the earth's magnetic field is 7,000 years, but there are certain differences with latitude. The time required for the magnetic field to change direction in low latitudes is half that of mid-high latitudes. This conclusion is exactly the same as that predicted by the magnetic field reversal geometric model.

cause

     The magnetic field is a very important attribute of the earth. People invented the compass based on the phenomenon of magnetic poles, but the magnetic poles of the earth are not always constant, but often inverted.

     There is no definite answer as to why the magnetic poles reverse. Since the creation of the earth, the direction of the magnetic field has been changing, but it is relatively slow.

     There are many theories about the reversal of the magnetic poles, and the more dominant ones are: the reversal of the magnetic poles is because the earth is in the large magnetic field of the Milky Way, and the reversal of the earth's magnetic poles is transformed by the reversal of the magnetic poles of the Milky Way. There is also: the result of continuous collisions of matter inside the earth, which causes the magnetic field inside the earth to constantly change. Also: the impact of a meteorite on the earth caused a change in the magnetic field. No matter what is said, it is a conjecture, and human beings will never stop exploring the earth and the universe.