The earth's magnetic field can protect us from the solar wind and cosmic radiation, so that life on earth can survive. But every 10 years or so, the earth's magnetic field always makes some "clean and jerk behaviors". "Geomagnetic mutation" refers to the sudden change of the intensity of the earth's magnetic field. Some magnetic field changes are gradual and will last for hundreds of thousands of years, but this drastic intensity change will only last for a few years at most, and only change the magnetism of a specific part of the earth at a time. For example, one of the first geomagnetic mutations recorded by humans occurred in 1969, which changed the magnetic field in western Europe briefly.

From then on, every 10 years or so, people will detect the sudden change of geomagnetic field somewhere in the world. But scientists still don't know the reason for this phenomenon. Many geomagnetic phenomena (such as auroras) are caused by the charged solar wind violently hitting the earth's magnetosphere, but scientists believe that geomagnetic sudden changes may originate from the deep core of the earth. The earth's magnetic field itself is formed by hot and constantly stirring liquid iron. However, the exact mechanism of this sudden change remains a mystery.

However, a new study published in the journal Nature Geoscience on April 22nd provides a possible explanation for this phenomenon. A new computer model of the physical behavior of the earth's core shows that geomagnetic sudden change may be caused by floating molten material released from the deep core.

Who is "making trouble"?

In this latest research, through unremitting efforts, researchers have established a set of computer models that can reproduce the physical conditions of outer nuclear. After 4 million hours of calculation (thanks to a French supercomputer, the calculation speed is greatly accelerated), the geomagnetic mutation produced by the simulation core is quite consistent with the actual mutation observed in the past decades.

These simulated geomagnetic abrupt changes will cause slight disturbance to the magnetosphere every 6 to 12 years. However, these mutations seem to stem from the buoyancy anomaly that occurred in the earth's core 25 years ago. When bubbles formed by molten substances float to the outer surface of the earth's core, they will produce powerful waves and spread rapidly along the magnetic lines near the earth's core, resulting in "drastic changes" in the liquid flow that dominates the earth's magnetosphere. Eventually, these sudden changes in the ground will appear at the height of the ground in the form of magnetic field disturbance.

"The sudden change of geomagnetic field is a big obstacle for us to predict the behavior of geomagnetic field in the next few decades." The author wrote in the paper, "If geomagnetic mutation can be reproduced in digital form, it will provide us with a new way to explore the physical characteristics of the deep earth."

The researchers pointed out that although the simulation results can't be confirmed by the actual observation of the core (the temperature and pressure near the core are extremely high and inaccessible), having such a model that can more accurately reproduce the geomagnetic sudden change in history may help us predict the geomagnetic sudden change that will occur in the future.

If we can know the occurrence time of geomagnetic sudden change in advance, it can also help scientists monitor and understand the influence of this phenomenon on other geodynamic processes. For example, a paper published in the journal Nature in 20 13 suggested that the sudden change of geomagnetic field may extend the time of one day. Researchers believe that a sudden change in core liquid flow may slightly change the rotation of the earth, resulting in an extension of one millisecond every six years and one day. According to the researchers' report, the extension of Earth Day does seem to be related to several well-known geomagnetic mutations.