Earth's magnetic poles will soon remain in place

Scientists have long found that the magnetic poles of our planet are relatively often interchanged. The magnetic south pole becomes north and vice versa. Such changes in the past happened more than once, and experts believe that the inversion will continue in the future. The last "substitution" occurred about 800 thousand years ago. Since the beginning of observations of the dynamics of the Earth’s magnetic field, scientists have noted a slight shift of the north and south magnetic poles and a slight change in the configuration of the field itself. Does this mean the beginning of a new offset period? Most likely no.

An international group of researchers studied inversions that happened millions of years ago. The periods between changes were also analyzed. Conclusion - now there is little that portends the next cycle of the "changing of the guard" by the poles, people can sleep peacefully.

But how can one understand what happened to the poles millions of years ago? For this it is necessary to study volcanic rocks. During their formation, the magnetic field of the Earth affects the magnetic particles inside the rocks. They get a kind of "magnetic signature", fixing the configuration of the Earth's field at the time of its formation. By the way, heating rocks to a certain level removes the “residual” configuration, reducing it to the current position of the poles.
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Earth’s magnetic field is heterogeneous. In some regions it is stronger, in others it is weaker. In order to obtain a single configuration of the magnetic field of the planet, scientists need to analyze the mass of data, which are then reduced to a global model.

So, after studying various rock samples, it turned out that in the period from 30,000 to 50,000 years ago, the magnetic poles of the Earth changed in an unusual way. Generally speaking, when the polarity changes, the magnetic field lines of our planet first take on a complex shape, and the magnetic field itself weakens - up to 10% of the initial value. At the same time, additional poles are formed, some of which can move towards the equator.

As it turned out, 41,000 years ago there was a very short-term (by geological measures) change of polarity. This event was called “the event lamp” , it lasted less than a thousand years. For 250 years, then the direction of the magnetic field of the planet also changed.

All this is interesting, but what does the “Lashamp event” or the inversion of the magnetic poles of 800 thousand years ago have to do with modernity? The good news is that no - that is, the modern configuration of the magnetic field does not look like that was thousands of years ago. Yes, there is a slight weakening of the magnetic field of the planet, but the overall configuration of the lines of this field does not change, moreover, there are no signs of the possible appearance of additional poles. And this, as scientists have found out, the main signs of an imminent pole shift.

The weakening of the Earth’s magnetic field has already taken place in the past. The cases closest to us are 48,500 and 46,300 years ago. In the first case, the magnetic field in the southern hemisphere weakened, in the second - a similar phenomenon occurred near South America. But there were no additional poles, no changes in the magnetic field vector or a pole shift, gradually the characteristics were corrected to the previous values ​​or parameters close to them.

The authors of the study in question believe that the forerunners of inversion are far from not only the weakening of the Earth’s magnetic field, but many other factors that are not present now.

If things are as scientists say, then this is really good news. The fact is that the Earth is protected by the magnetic field of the planet from rigid cosmic radiation. If the inversion had happened in our time, this would lead to numerous equipment malfunctions, from near-earth satellites to electronic devices on the surface of the Earth. In addition, this kind of radiation is harmful to living organisms. Probably, the global economy would have lost tens and hundreds of billions of US dollars, and problems in society would have started - wars, famines and similar “satellites” of the crisis.

Interestingly, scientists still do not know exactly why there is a magnetic field of the Earth. In our system, besides her, there is a magnetic field in Mercury, the Earth, four gas giants and Ganymede. Most likely, the magnetic field is generated by a metal core in the center of the planet (in the case of the Earth) with a relatively solid center and a liquid shell. The theory of the generation of a magnetic field by a nucleus is called a magnetic dynamo . It is generally accepted, but this does not mean that it has no flaws. The fact is that over time, the dynamo effect should die out and the core of the planet should gradually cool down.

DOI: 10.1073 / pnas.1722110115