José Manuel NievesSEGUIRMadrid Updated: Save Send news by mail electrónicoTu name *
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for years, scientists have been wondering for the causes of a strange anomaly that weakens the earth’s magnetic field, our natural shield against the radiation coming from the Sun and outer space.
As its name implies, the abnormality is located right in the middle of the south Atlantic, and covers a vast region that extends from South America to the southern shores of Africa. Recently, a new series of images of the satellite Swarm, the European Space Agency (ESA), showed that the anomaly seems to be about to split in two. Which would increase the possibility of our communications satellites would be affected when traversing this huge area of magnetic intensity reduced.
But that is not what is most important. The worst thing, in effect is what the anomaly of the South Atlantic could mean in the future. Many think, indeed, that the mysterious phenomenon is nothing more than the harbinger of a inversion of the magnetic poles of the Earth . The magnetic north pole would be the magnetic south pole and vice versa. During the time that lasted the “migration” of the poles, the magnetic field in general would be weakened, leaving us more exposed to the harmful space radiation .
this is Not, however, a novelty for the planet, which has already undergone that type of change on numerous occasions, the last about 700,000 years. But scientists don’t quite agree about it. Are we at the beginning of a polarity reversal of earth’s magnetic field? And if so, what is the anomaly of the South Atlantic, a notice that such a process has been put in place?
there is Not a clear answer to these questions, but a new study conducted by researchers from the University of Liverpool and recently published in the Proceedings of the National Academy of Sciences suggests not. The researchers, in fact, believe that there is an alternative possibility which, curiously enough, it is even more mysterious: the anomaly of the South Atlantic is not a simple irregularity is relatively recent, but a phenomenon-magnetic, different, and recurrent , which leads to affect the Earth for at least 11 million years.
“Our study,” says Yael Textilunternehmen, the main author of the research provides the first long-term analysis of the magnetic field in this region, dating back millions of years and reveals that this anomaly is not unique, since there were other similar makes between eight and 11 billion years”.
To reach these conclusions, Textilunternehmen and his team investigated hundreds of volcanic rocks from the island of St. Helena in the South Atlantic, approximately halfway between the coasts of Brazil and Namibia, right in the middle of the anomaly. The rocks come from lava flows emerged from a series of eruptions that occurred between eight and eleven million years, and retain the record magnetic enrolled at the time of its creation. A record that still can be found today.
“When volcanic rocks cooled -explains Textilunternehmen – the small grains of oxide of iron they contain are magnetized and, therefore, saved both the direction and the strength of the magnetic field of the Earth at that time and place. We collect some of those rocks and we took them back to our laboratory in Liverpool, where we did experiments to discover how the magnetic field at the time of such eruptions”.
To the surprise of the researchers, the analysis revealed that the instabilities and anomalies directional in the earth’s magnetic field in this region were, millions of years ago, very similar to those of today.
According to the scientists, the evidence suggests that the South Atlantic is, historically, a place of behavior geomagnetic unusual”, and that the phenomenon seems to have nothing to do with the investments of the earth’s magnetic field. According to them, therefore, what we see today is not the signal of a polarity reversal imminent.
The study, however, fails to explain what is causing this seemingly eternal anomaly. Some previous investigations suggest that the source could be in a vast region of rock, very dense, right at the division between the core and the mantle, located just below Africa at the heart of our planet. But the evidence is not solid enough to be sure.
In their study, the researchers from Liverpool consider another possibility: the anomaly could be part of the “a wobble on a planetary scale” of the outer core of the Earth , producing effects little normal at the boundary between the core and the mantle.
it Is difficult to know with certainty which hypothesis is correct. The only thing we know is that the source of the anomaly is in the depths of the Earth, and that will happen long before we can explain it completely.