(ORDO NEWS) — The protective shell of our planet is not quite the same as it used to be. Over the past two centuries, its magnetic strength has plummeted, and no one has the slightest idea why.
At the same time, a relatively soft spot in the area, called the South Atlantic Anomaly, suddenly formed over the Atlantic Ocean and already had a negative impact on orbiting satellites, which began to break as they flew over it.
Both of these disturbing observations raise concerns that we may be seeing signs of an imminent reconfiguration that will manifest itself in a reversal of the magnetic pole.
But the researchers behind the new study, which models the planet’s magnetic field in the recent past, warn that it’s far from certain that this will happen.
“Based on the similarity to the reconstructed anomalies, we predict that the South Atlantic Anomaly is likely to disappear within the next 300 years and that the Earth is not moving towards a polarity reversal,” says Andreas Nilsson, a geologist at Lund University in Sweden.
If so, then we can probably breathe easy.
However, judging by our geological history, it is likely that the fluid lines of our planetary magnetic field will eventually point the other way.
The last time this global event occurred (only 42,000 years ago), life on Earth seemed to be going through a difficult period. At that time, a rain of high-speed charged particles tore through our atmosphere.
Given today’s reliance on electronic technology, which can be vulnerable without the protection of a magnetic umbrella, even the most rapid field changes will leave us unprotected for the foreseeable future.
Therefore, geologists are in a hurry to find out which fluctuations and wanderings in the field portend disaster, and which ones make the business move actively.
Much of what we know about the history of the magnetic field has to do with how its orientation causes particles in molten materials to line up before being locked in place as they solidify. Digging through the layers of mineralized needles provides a fairly clear record of which way the compass has pointed over the millennia.
Similarly, ceramic artifacts can also provide a snapshot of the field in more recent times, fixing its direction in clay before firing.
In a new study, researchers at Lund University and Oregon State University have recreated a detailed timeline of the Earth’s magnetic shell extending back to the last ice age by analyzing samples of volcanic rocks, sediments and artifacts from around the world.
“We have mapped changes in the Earth’s magnetic field over the past 9,000 years, and anomalies like the one in the South Atlantic are likely to be recurring phenomena associated with corresponding changes in the strength of the Earth’s magnetic field,” says Nilsson.
Looking back thousands of years, it quickly becomes clear that a soft spot in the South Atlantic is not entirely unusual. Starting around 1600 BC, a similar geological change took place, lasting about 1300 years.
It is likely that the current weakening area will soon regain its strength and disappear without ending with global changes in the Earth’s magnetic field. It is possible that the magnetic field as a whole will return to a strength we have not seen since the early 19th century.
However, this is not proof that a somersault of the magnetic field will soon occur. It is simply evidence that we should not interpret the waning strength anomalies that have been detected as signs of a pole reversal.
In some ways, this is good news, but it leaves us in the dark about exactly what such a massive geological process would look like on the scale of a human lifetime.
Having detailed records goes a long way in creating a clearer picture, as if that happens then we’ll be ready.
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