Earth's magnetic poles will probably not turn around after all, scientists predict

Earth’s magnetic poles will probably not turn around after all, scientists predict

Our planet’s protective shell is not quite what it used to be. For the past two centuries, its magnetic force has taken a deep dive, and no one has the dumbest idea why.

At the same time, a disturbingly soft spot in the field called the South Atlantic Anomaly has blown across the Atlanticand has already been shown to be problematic for sensitive circuits on satellites.

Both of these disturbing observations give rise to concern that we may see signs of an imminent reconfiguration that would make the compass points completely unclear in what is called a magnetic pole reversal.

But scientists behind a new study that models the planet’s magnetic field in the recent past warn that we should not be in too much of a hurry to assume that it will happen.

“Based on similarities with the recreated anomalies, we predict that the South Atlantic anomaly will probably disappear within the next 300 years, and that the Earth is not heading for a polarity reversal.” says geologist Andreas Nilsson from Lund University.

Not soon, at least. So now we can breathe easy.

Still, if our geological history is anything to go by, it is likely that the flowing lines of our planetary magnetic field will eventually point in the other direction.

What such a turnaround would mean for humanity is not clear. The last time such a monumental event occurred, just 42,000 years agolife on earth seemed to go through a tough period when a rain of charged particles at high speed tore through our atmosphere.

Whether we humans noticed – perhaps responded by spending a little more time on protection – is a matter of speculation.

But given today’s dependence on electronic technology that can be vulnerable without the protection of a magnetic umbrella, even the fastest field reversals in the foreseeable future would leave us vulnerable.

So geologists are anxious to know who is wobbling, wobbling and hikes in the field heralds disaster, and that involves business as usual.

Much of what we know about the history of the magnetic field coming from the road its orientation forces particles in molten material to line up before being locked in place as they solidify. Digging through layers of mineralized arrows gives a fairly clear picture of which way the compass pointed during the millennia.

Similarly, ceramic artifacts from archeological sites can also provide a recent snapshot of the field, capturing its direction in clay before firing.

In the new study, researchers from Lund University and Oregon State University reconstructed a detailed timeline of our planet’s magnetic shell that stretches back to the last ice age, by analyzing samples of volcanic rocks, sediments and artifacts from around the world.

“We have been mapping changes in the Earth’s magnetic field over the past 9,000 years, and anomalies such as the one in the South Atlantic are probably recurring phenomena linked to corresponding variations in the strength of the Earth’s magnetic field.” says Nilsson.

With thousands of years of perspective, it quickly becomes clear that the South Atlantic soft spot is not completely out of the ordinary. Beginning around 1600 BC, a similar geological change took place, which lasted for about 1,300 years before it went out again.

Assuming the same basic mechanics work, it is likely that the current weakening will soon regain strength and disappear without ending in global reconfiguration. It is even probable that the magnetic field as a whole will bounce back to a force we have not seen since the beginning of the 19th century.

However, this is not proof that a turnaround will occur soon – only new evidence suggests that we should not interpret current anomalies of diminishing strength as strong signs of a polar flip.

Somehow it’s good news. But it leaves us in the dark about exactly what such a massive geological process will look like on the scale of a human lifetime.

Having detailed records like this goes a long way towards building a clearer picture, so if the worst happens we may be prepared for it.

This research was published in PNAS.

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