Magnetic poles of the Earth will not turn over in the coming years, say scientists

© Fotolia / Petrovich12Магнитные poleMagnetic poles of the Earth will not turn over in the coming years, say scientists© Fotolia / Petrovich12

A further weakening of Earth’s magnetic field is unlikely to lead to a dramatic upheaval of its poles in the vicinity of the anomalies recently found by geologists in South Africa, say scientists in an article published in the journal PNAS.

«Recently people often say that the Earth will soon experience the next revolution of the poles. The study of two recent events showed that none of them like the changes in the magnetic shield of the planet that capture scientists today. It is therefore extremely unlikely that something similar will happen in the near future,» said Richard Hill (Richard Holme) from the University of Liverpool (UK).

The position of the poles and the direction of the compass needle is a permanent feature of the planet. Periodically, about once in 450 thousand or a million years, the North and South poles of the planet changed places, the traces which the scientists discovered the structure of ancient clay and volcanic rock. For example, about 40 thousand years ago, the North needle of a compass would point to the South pole and South to North.

Two years ago, geologists from the University of Rochester (USA) made an amazing discovery, they were able to detect extremely unusual magnetic anomaly in South Africa from the banks of the Limpopo river, where the magnetic field strength fell sharply and fallen to critically low values in the XIII-XVI centuries of our era.

This is the first time pointed to the fact that the upheavals of the Earth’s poles do not occur randomly, but at specific points with anomalous properties, where mantle rocks close to surface and thus interfere with the normal circulation of substances in the core of the planet.

Such a perspective has led scientists to verify any changes in the strength of the magnetic field of the Earth in this point and in other time periods — the Antiquity, the Middle ages and the last two centuries. As it turned out, the Earth’s magnetic field drastically weakened at this point of Africa at least three times during the fall of the Roman Empire and at the beginning and end of the Middle ages.

Hill and his colleagues have tested, it seems if the current weakening of the magnetic field at this point South Africa that took place 40 and 36 thousand years ago when the pole was last interchanged or was close to it. To do this, scientists have collected samples of minerals, occurred shortly before these disasters, and checked which side was «rotated» field, trapped in crystals of iron and other magnetic materials in the strata of these rocks.

This allowed geologists to reconstruct the history of how varied the strength of the magnetic field of the Earth and how to change the position of the poles directly in front of these revolutions, and compare that with what happened with the Earth in the last half century, creating a computer model of the ancient magnetic field of the planet.

As shown by these calculations, between the last change of the poles of the Earth and the current weakening of its magnetic field have almost nothing in common. In particular, the shield of the planet is weakening too slow to ensure that its magnetic axis flipped in the next few thousand years.

Most likely, the field strength will continue to fall for another few centuries or thousands of years, after which it will smoothly start to grow, without causing large-scale changes in the bowels of the Earth. Where it leads and when it will begin, geologists do not yet know.