The Earth's magnetosphere doesn't just endow our planet with magnetic north and south poles. It also protects us from solar wind and cosmic radiation. However, this invisible power is rapidly weakening. And so much so that scientists even begin to say that after some time the magnetic field may turn over, and the poles of the planet will change places.
As crazy as it sounds, this has happened before. The last time the inversion took place was about 780,000 years ago and, according to some scientists, may occur again in about 40,000 years. With the latter, scientists are not sure, and it is this uncertainty that makes them look for answers. At the same time, the researchers say that even if this reversal of polarity does happen in the future, it will not happen quickly, but over several thousand years.
Of particular interest to scientists at the moment is the so-called South Atlantic Anomaly (SAA) - a huge area of the planet's magnetic field, stretching from Chile to Zimbabwe. It is this phenomenon, according to scientists, that is now causing the Earth's magnetic field to weaken. Here its strength is so weak that it poses a threat to orbiting satellites that may pass through it. The researchers shared their work in the journal Geophysical Review Letters.
Imagine that the Earth's magnetosphere is an orange peel. Everything that is under this skin is protected from harmful influences from the outside. SAA, in turn, is a deep dent in this skin. All satellites in low Earth orbit of the Earth are also under the skin, but, passing through the SAA (dent in the skin), go out from under its protection, and their electronics becomes defenseless against the destructive streams from space. That is why all vehicles suspend their work when flying over the SAA.
“We have known for a long time that the magnetic field in this area changes. But we didn’t know if this was always typical for this region or if it was a particular phenomenon,”says physicist Vincent Hare of the University of Rochester (USA).
One of the reasons why scientists know little about the history of the magnetic field in this region of the Earth is the lack of archaeomagnetic data - physical evidence about Earth's magnetism that could be preserved in archaeological relics of the past.
Nevertheless, one such evidence from the past has survived, and it is associated with the ancient African people who lived in the valley of the Limpopo River, stretching across the territories of Zimbabwe, South Africa and Botswana - regions currently located within the South Atlantic anomaly.
Life in Africa has always been difficult. But about 1000 years ago, when the inhabitants of these places faced special environmental difficulties, they performed sacred rituals. During especially dry seasons, people burned their clay dwellings and grain storage, thus trying to appease the gods and convince them to give the long-awaited rains. Certainly these ancient Africans did not even suspect that with their rituals they would create an invaluable ground for scientific research for those who will live several centuries after them.
Promotional video:
Clay, like everything that exists on Earth, has a pronounced energy and has its own information field, which, among other things, can contain information about the planet's magnetic field.
“When you heat clay to a certain temperature, you actually stabilize the magnetic minerals it contains. In these minerals, the 'imprinted' information about the magnetic field is erased and overwritten with the current state of the field,”explains geophysicist John Tarduno.
In other words, the analysis of these clay artifacts allows scientists not only to find out more about the cultural characteristics of ancient peoples who lived thousands of years ago in South Africa, but also to learn about what the Earth's magnetic field was at that time.
“We looked for signs of repetitive behavior because we believe that they are the reason for the existence of the South Atlantic anomaly today. And we really found them. This information helps us to contextualize the current changes in the magnetic field,”says Tarduno.
The study showed that the current weakening in the SAA is not a separate phenomenon in the history of the Earth, but has occurred several times in the past. Similar changes, scientists say, should have been observed in 400-450 years. n. BC, 700-750 BC n. e., as well as in 1225-1550. n. e. And this information indicates that the location of the South Atlantic Anomaly is not a simple geographic fluke.
“We are beginning to receive strong evidence that Africa has something unusual. Something that can have an important impact on the overall state of the Earth's magnetic field,”adds Traduno.
There is an assumption that the weakening of the planet's magnetic field, which has been observed for about the last 160 years, is caused by the so-called "African low-velocity mantle provinces" or African superplumes (hot mantle flows moving from the base of the mantle at the core of the Earth, regardless of convective currents in the mantle) located at a depth approximately 2900 kilometers under the African continent.
“This geological feature must be several tens of millions of years old. It stretches for thousands of kilometers, but has very distinct boundaries,”scientists say.
These dense currents exist in the boundary layer between the mantle and the core of the planet and, according to some assumptions, may somehow cause disturbances in the intraterrestrial sources that generate it. But before we can know everything for sure, it will take more than a dozen large-scale scientific research.
Experts say that, according to the idea of a change of poles, the beginning of this event will be initiated by processes occurring directly in the very core of the planet, but the results of the latest study suggest that everything that happens to the magnetic field around the Earth is strongly associated with phenomena occurring in certain areas. border area between the core and the mantle. If this is really so, then hardly anyone would have thought that we would owe the solution of this complex riddle to an ordinary ancient ritual that was practiced a millennium ago. However, scientists are not yet ready to answer the question of what all this means for our future.
“We now know that these changes in the magnetic field have occurred several times in the past. And the last of them has been observed for the last 160 years. Based on this, we can conclude that all these events are part of one whole, something larger,”the researchers say.
"But it is too early to say whether these changes will actually lead to a change in the planet's poles."
Nikolay Khizhnyak