They discover why the magnetic north pole moves so fast towards Siberia

For some years now, more and more scientists have been wondering why the magnetic north pole (not to be confused with the geographical north pole), is moving rapidly towards Siberia at a rate of about 50 km per year . Are we perhaps at the beginning of a polarity reversal, during which the north and south (magnetic) poles exchange their positions?

Now, a team of researchers from the British University of Leeds believe they have found the solution to the puzzle. Based on the analysis of 20 years of satellite data, the position of the magnetic north pole largely depends on the titanic competition between two lobes with different magnetic force at the boundary separating the core from the Earth's mantle, just below Canada. The finding has just been published in Nature Geoscience .

A North Pole on the Run

Unlike our geographic north pole, which is in a fixed location, magnetic north moves continuously from one place to another. This fact has been known since it was first measured in 1831 and it was verified, over time, how this site slowly drifted from the Canadian Arctic to Siberia and at an average speed of 15 km per year.

But since the early 90s that slow drift has inexplicably become a kind of crazy race , moving at speeds ranging from 50 to 60 km per year. This sudden change of pace has had, and has, global consequences. In fact, the Global Magnetic Model, on which, for example, the GPS systems of ships and planes are based or the smart maps of our phones, must be continually updated. Otherwise, we and the world's main means of transportation would literally lose the north.

The dynamo of the heart of the Earth

The Earth's magnetic field exists thanks to the rotation of a true ocean of liquid iron (the outer core) around the solid (also iron) core of the Earth. Like the dynamo of a bicycle, all that moving iron creates electric currents, which in turn generate our magnetic field.

Models based on measurements from space have allowed scientists to make global maps of that field . The ongoing changes, moreover, help them understand how liquid iron is moving "down there."

According to Phil Livermore , first signatory to the paper, "By analyzing the magnetic field maps and how they change over time, we can now determine that a change in the flow pattern of the flow below Canada has caused a patch in the magnetic field to stretches on the edge of the core, deep in the Earth. And that has weakened the Canadian patch and caused the pole to shift to Siberia. "

The decline of the Canadian patch

In other words, historically the Canadian patch was the strongest in this war, and so the magnetic north pole was centered in Canada. But in recent decades, the Canadian patch has stretched and lost strength compared to the Siberian patch , which has strengthened. This explains why the pole has accelerated and suddenly abandoned its historical position.

The big question, and that still has no answer, is whether the pole will ever end up returning to Canada or whether it will continue to move away and move south. According to Livermore, "The models of the magnetic field suggest that, for at least the next few decades, the pole will continue to move towards Siberia . However, since the position of the pole is governed by this delicate balance between the Canadian and Siberian patches, a slight adjustment in the core would suffice to send the pole back to Canada.