The earth’s magnetic field is gradually weakening in a huge area that stretches from Africa to South America. Like recent satellite data from the European Space Agency, the development is taking on new dimensions. But what is happening and why do scientists suspect a polar reversal? Let’s find out.
This phenomenon of the so-called South Atlantic anomaly is closely observed by geophysicists since the magnetic field of the earth is vital for our planet. Earth’s magnetic field keeps out cosmic radiation and protects us from solar winds. In addition, the magnetic north and south poles are determined.
Anomaly Is Continuous
On average, the earth’s magnetic field has lost about 9 percent of its strength over the past 200 years. In the area of the South Atlantic Anomaly, the magnetic flux density decreased from 24,000 nanoteslas to 22,000 nanoteslas between 1970 and 2020.
In the meantime, the magnetic field in the southern hemisphere has grown and moved westwards. On average, it moves at a speed of 20 kilometers in a year. Along with that, an additional center of the magnetic field west of South Africa has been developing for 5 years. This could also mean that the South Atlantic Anomaly could split into two magnetic fields in the coming years.
The Second Center Is In Africa
As new measurements show, a second center with minimized magnetic intensity has also been created in the past five years southwest of Africa. The researchers suspect that this suggests that the South Atlantic anomaly could split into two separate regions.
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The original center is located above the middle of South America and the new cell off the coast of Southwest Africa. The new, eastern minimum of the South Atlantic Anomaly has emerged in the past ten years and has developed vigorously in the past few years.
How Is The Magnetic Field Generated
The magnetic field is largely generated by the currents of liquid iron in the outer core of the earth, which begins on average 2900 kilometers below the surface and extends to a depth of up to 5150 kilometers. Hot magma is continuously flushed up to the Earth’s mantle, it cools there and sinks again into the depth, while the Earth’s core rotates.
These overlapping movements lead to a kind of dynamo effect which creates electricity and the magnetic field.
There is speculation that the current weakening of the field is a sign that the earth is heading for a polarity reversal, in which the magnetic north and south poles swap places.
Is a Pole Shift Approaching?
It is now speculated whether the recent redesign of the magnetic fields will result in a polarity reversal of the earth’s magnetic field. The magnetic fields of the north and south poles swap places.
This has happened several times in the history of our home planet, on an average every 250,000 years. The next so-called pole shift is long overdue from a statistical point of view since it last happened about 780,000 years ago.
Malfunctions in Satellites Possible
According to scientists, there is currently no need to worry about the magnetic field shifts. However, satellites and other spacecraft flying over the South Atlantic Anomaly area are likely to experience technical problems because the magnetic field is weaker in this region.
Because of the weak magnetic field, charged particles can penetrate into the low earth orbit more easily.
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Is It Really Polar Reversal or Something Else?
The polar reversal has occurred many times throughout the history of our planet. Given the average speed at which these reversals take place which is about every 250,000 years, the next one would be long overdue. However, the intensity decline now occurring in the South Atlantic is still within the fluctuation level that is considered normal.
Another theory is that the South Atlantic anomaly could be caused by a huge reservoir of dense rock under the African continent. It might be blocking the magnetic field from reaching the earth’s surface and the atmosphere. Though, the real cause is yet to be established.