Earth's magnetic field behaves unexpectedly – and defeats scientists | Science and health

Because of its liquid metal core, the Earth operates as a huge magnet with positive and negative poles. The magnetic field is a "layer" of forces around the planet between these two poles.

Known as the magnetosphere, this great layer is extremely important for terrestrial life.

"It's the magnetic field that protects us from particles from the outside, especially the solar wind (which can be very damaging)," says geologist Ricardo Ferreira Trindade, researcher at the # 39; Institute of Astronomy and Geophysics of the University of São Paulo (USP)

The essential magnetic field is generated by the movement of liquid metals constituting the center of the planet. As the flow varies, the field changes.

According to Trinity, the question is that over the past ten years she has "varied at a much greater speed than before".

The North Pole is constantly changing magnetic position, but still within limits. Although the direction of these changes is unpredictable, the speed was constant before.

However, in recent years, magnetic north has moved from Canada to Siberia at a much faster rate than scientists expect.

This change requires geomagnetism specialists to update the global magnetic model, a kind of map describing the magnetic field in space and time.

"It is created from a set of observations made over five years around the world, from which is badembled a global model that changes over time and in space, showing the variability of the field, "says Trindade. . "It's a kind of 4D card."

The model is important because it forms the basis of hundreds of modern navigation technologies, ranging from ships' road controls to Google Maps.

"It's fundamental for geolocation and even satellite positioning," says the geologist.

The latest version of the model was completed in 2015 and is expected to last until 2020, but the speed with which the magnetosphere has changed forces scientists to update the model in advance.

In addition to pole shift, an electromagnetic pulse detected in South America in 2016 caused a change shortly after the model was updated in 2015.

The many unexpected changes have increased errors in the time of the current model.

According to Nature, researchers from Noaa (Center for Oceanic and Atmospheric Administration) in the United States and the British Geological Survey Center realized that the model was so obsolete that it was nearing the limit acceptable – and was about to generate possible errors. navigation.

The new update is scheduled for January 30, 2019, according to Nature, one of the world's most prestigious scientific journals.

The model is also essential for the security of the space.

Since the distribution of the field is not homogeneous, the lower it is, the lower the protection it offers. This means that these areas, especially at very high altitudes, are a little more vulnerable to solar winds.

"We have regions where it is bigger and others where the magnetic field is very weak." Here (in South America) we have a big anomaly that makes the magnetic field of low intensity "explains Ernesto.

"Atmospheric equipment, satellites and telescopes are more likely to be damaged if they fly over these areas," he says.

Scientists strive to understand why the magnetic field changes so rapidly.

"The field is very variable and very unpredictable," says geologist Marcia Ernesto, also a researcher at the Institute of Astronomy and Geophysics at the University of São Paulo (USP).

The displacement of the North Pole could be linked to a jet of liquid iron moving beneath the surface of the Earth's crust in the region under Canada, according to a study by researchers from the University of Leeds published in Nature Geoscience in 2017.

Philip W. Livermore, one of the authors of the study, said that the jet could weaken the magnetic field in Canada, while that of Siberia remains powerful, which " would lead "magnetic north to Russia.

The field is so variable that the magnetic North Pole and South Pole have already been inverted several times since the formation of the planet.

Its current configuration is the same as 700,000 years ago, but can begin to reverse at any time. According to Ernesto, this reversal would take about a thousand years.