As crazy as it may sound, but this has happened before. Last time inversion occurred about 780 000 years ago and, according to some scientists, it may happen again after about 40 000 years. With the latest scientists are not sure, and this uncertainty makes the search for answers. At the same time, the researchers say that even if this change of polarity will really happen in the future, then it will not happen quickly, and within a few thousand years.
Of particular interest to scientists at the moment is the so-called South Atlantic anomaly (UA)– a huge area of the magnetic field of the planet, stretching from Chile to Zimbabwe. It is this phenomenon, according to scientists, causing many to weaken the Earth's magnetic field. Here his power is so weak that it poses a threat to orbiting satellites, which are unable to pass through it. About their work, the researchers shared in the journal Geophysical Review Letters.
Imagine that the magnetosphere of the Earth is the orange peel. All that is under that skin is protected from harmful influences from outside. UAA, in turn, is a deep dent on the skin. All satellites in low earth orbit the Earth, too, are under the skin, but walking through OIA (a dent on the skin), out from under its protection, and their electronics are defenseless against the destructive flows of space. That's why all devices are paused, flying over UAE.
"We have long known that the magnetic field in this region changes. But we didn't know whether this was peculiar to this region or is a private phenomenon," says physicist Vincent hare from the University of Rochester (USA).
One of the reasons why scientists, little is known about the history of the magnetic field in this region is the lack of archeomagnetic data – physical evidence of the magnetism of the Earth which could be preserved in the archaeological relics of the past.
However, one such evidence of the past is preserved, and it is connected with the ancient African people who lived in the valley of the Limpopo river, extending to the territories of Zimbabwe, South Africa and Botswana regions at the moment inside the South Atlantic anomaly.
Life in Africa has always been complicated. But about 1000 years ago, when the inhabitants were faced with particular environmental challenges, they conducted sacred rituals. During particularly dry seasons, the people burned their clay homes and grain stores, thus attempting to appease the gods and convince them to give the long-awaited rains. Definitely these ancient Africans were unaware that by their rites they will create an invaluable ground for research for those who will live a few centuries after them.
Clay, as with everything that exists on Earth has a pronounced energy and has its own information field, in which, among other things, may include information about the planet's magnetic field.
"When you heat the clay to a certain temperature, in fact stabilizarea contained magnetic minerals. In these minerals "printed" information on the magnetic field is erased and overwritten by the data on the current state of the field", explains geophysicist John Tarduno.
In other words, the analysis of these clay artifacts allows scientists not only find out more about the peculiarities of the ancient peoples who lived thousands of years ago in South Africa, but also to learn about what was at that time the Earth's magnetic field.
"We were looking for signs of repetitive behaviors, as we believe that they are the reason for the existence of the South-Atlantic anomaly today. We do found. This information helps us to contextualize the current changes the magnetic field," says Tarduno.
The study showed that the current weakness in UAE is not an isolated phenomenon in the history of the Earth, as happened several times in the past. Similar changes, the researchers say, had to occur in the 400-450 ad, 700-750 ad, and in 1225-1550 ad And this information indicates that the location of the South Atlantic anomaly is not simply a geographical accident.
"We're starting to see conclusive evidence that Africa has something unusual. Something that can have an important impact on the overall state of Earth's magnetic field," adds Traduno.
There is speculation that the weakening magnetic field of the planet, observed for approximately the last 160 years, invoked the so-called "African low-velocity mantle provinces" or African superplumes (hot mantle flows, moving from the base of the mantle from the Earth's core, regardless of convection currents in the mantle), located at a depth of about 2900 kilometers below the African continent.
"That geological features must be several tens of millions of years. It stretches for thousands of kilometers, but has a very distinct border," say the researchers.
These dense flows exist in the boundary layer between the mantle and core of the planet and, according to some assumptions, can somehow cause disturbances of the intracrustal sources that generate it. But before we can find out for sure, you will need to hold more than a dozen large-scale scientific research.
Experts say that, according to the idea of pole shift, the beginning of this event will put the processes occurring directly in the core of the planet, however, the latest research suggests that all that is happening with the magnetic field around the Earth, closely connected with the phenomena occurring in certain areas of the border region between the core and the mantle. If this is true, it is unlikely that someone could think that the solution to this complex riddle, we will have the usual ancient ritual practiced thousands of years ago. However, scientists are not yet ready to give an answer to the question about what it all means for our future.
"Now we know that these changes in the magnetic field arose several times in the past. And the last one observed in the last 160 years. Based on this, we can conclude that all these events are part of one whole, of something bigger," say the researchers.
"But it is too early to say whether these changes will be able to lead to a change of the poles of the planet."