The Earth's magnetic field is a kind of invisible superhero: it is always there, to protect us from radiation, ready to deflect the most harmful particles from the Sun. Like all superheroes, however, he too has moments of crisis. Some clues really suggest that we are about to undergo an epochal revolution: a new reversal of the magnetic field.
The mystery of magnetic reversal
We still don't have a definitive explanation as to what causes the magnetic field to reverse. However, scientists think that the phenomenon may be linked to the dynamics of terrestrial core: in particular the outermost one, which is in the molten state. This moving nucleus gives birth to something called geodynamo, a phenomenon that generates our magnetic field.
Over time, the geodynamo undergoes variations. Alterations that lead the magnetic field to weaken and move chaotically until it reaches a complete inversion, with the north and south magnetic poles exchanging places.
Hints of an impending reversal
Why do scientists think we are about to see a reversal of the magnetic field? There are two main clues that led them to this conclusion.
First, an anomaly we told you about some time ago. It is an area of weak and expanding magnetic field, called South Atlantic anomaly, which covers approximately 20% of the Earth's surface. This phenomenon is usually a warning sign of an impending reversal.
Second, the last reversal was 780.000 years ago, a period more than double the average between two events. In other words, we would even be "late" on the expected times for this phenomenon to occur.
A… multipolar future
No, I'm not talking about geopolitics. Scientists' analyzes believe it is probable that even more magnetic poles will be created before the magnetic field inversion, and this aspect is very worrying.
Why? The effects could weaken our natural shield: a sort of "kryptonite" for our superhero, the magnetic field, which would make him lose up to 90% of his ability to shield us.
The consequences? Strong increase in the effects of solar winds, with a consequent increase in cases of cancer, technological malfunctions (many of our satellites and telescopes could suffer irreparable damage) and areas of the Earth that would become uninhabitable.
When will it happen? And how long?
It's frustrating not knowing exactly when it will happen, but this phenomenon somehow hangs over us: scientists do well to prepare for this eventuality, by studying the phenomenon and trying to predict its effects.
We only have a vague inkling of the impact of something like this. It comes to us from the study of an "episode" from over 40.000 years ago called Laschamps excursion. A relatively rapid reversal (250 years) with catastrophic effects. Let's hope it's nothing like this: after all, second another study the reversal of the magnetic field that occurred 780.000 years ago took 20.000 years to complete.
If so, better slowly.
