Le noyau interne de notre Planète a joué un rôle important dans le maintien de son champ magnétique protecteur. Lui évitant de finir aussi sèche que la planète Mars. © dimazel, Adobe Stock

Why didn’t Earth have the same fate as Mars?

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[EN VIDÉO] A Reversal of Earth’s Magnetic Field May Have Changed Our History
According to The Guide of the Galactic Traveler written by Douglas Adams, the answer to everything is to be found in the number 42. And researchers from the University of New South Wales (Australia) wink at him by revealing that a reversal of the magnetic field of our Earth which occurred 42,000 years ago had important consequences on the environment of our ancestors. She may even have led Neanderthal to his downfall. (in English) © University of New South Wales

The planet Mars is now desert. Somewhere in its past, it lost the water that flowed over its surface. She also lost a lot of her atmosphere. In question, according to astronomersthe dissipation of the Magnetic Field, magnet and field…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/6/a/a/6aa47f5f22_85914_champ-magnetic.jpg” data -url=”https://news.google.com/science/definitions/physics-magnetic-field-3878/” data-more=”Read more”>magnetic field which until then protected it from This wind is not very dense (10 particles per cubic centimetre), but very fast (400 to 800 km/s). It’s a supersonic wind (it moves faster than waves…” data-url=”https://news.google.com/sciences/definitions/univers-vent-solaire-2445/” data-more =”Read more”>solar winds.

Our Earth remains sheltered from its own magnetic field. It is the result of the movements of liquid iron bubbling some 2,900 kilometers below our feet. In what scientists call the outer core. Movements of convection on a very large scale that produce a Electric power. It is this electric current which generates a magnetic field by dynamo effect.

But about 565 million years ago, the intensity of this magnetic field dropped by about 10%. Before suddenly returning to normal. Just before what researchers call thecambrian explosion. One of the most significant events in the history of life on Earth. The sudden appearance of multicellular life forms.

Note that, when geologists evoke a process which occurred “all of a sudden”, it must be understood that it took a few tens of millions of years… only. Of the University of Rochester scientists (USA) now show that the process in question coincided with the formation of the Earth’s solid inner core.

A story to read in the rocks

“Just before the inner core begins to expand, the Earth’s magnetic field was about to collapse. But as soon as the inner core grew, the magnetic field regenerated.”underlines John Tarduno, geophysicist, in a statement from the University of Rochester.

To determine how the magnetic field and the core of our Earth have evolved over time, the researchers relied on an analysis of minerals brought to the surface and containing tiny magnetic particles that record the direction and strength of the magnetic field as the minerals cool. They were thus able to fix two new important dates in the history of the inner core of our planet.

550 million years ago, the Earth’s magnetic field renewed itself after a near collapse only 15 million years earlier. A renewal related to the formation of a solid inner core which has somehow recharged the outer core in The melting point of water, in other words the temperature at which the ice…” data- image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/7/d/0/7d0df59f3c_82086_fusion.jpg” data-url=”https://news.google.com/sciences/definitions/ physics-fusion-15305/” data-more=”Read more”>merger ; and 450 million years ago a boundary was formed between the innermost inner core and the outermost inner core. An evolution which coincides with changes in the structure of the The mantle, however solid, is animated by convection currents which…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal /7/4/6/7466fb8049_50004180_terre-270907.jpg” data-url=”https://news.google.com/planete/definitions/structure-terre-terrestrial-mantle-2495/” data-more=”Read the more”>coat underlying, due to the Drift of…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/9/f/c/9fcec5bdc0_45137_plates-tectonics-wikimediacommons- dp.jpg” data-url=”https://news.google.com/planete/definitions/geologie-tectonique-plates-970/” data-more=”Read more”>tectonic plates.

Better understand the inner core dynamics and the magnetic field allows us to better understand the past of our Earth. But also, to consider its future. “Difficult to know if our Earth would have ended up like Mars if the When this collapse concerns coherent rocks, we can also speak of a rockslide.
The result of this…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/f/6/7/f678fd3677_50035322_eboulement-cmic-blog-cc-nc-2.jpg ” data-url=”https://news.google.com/planete/definitions/sustainable-development-landfall-6515/” data-more=”Read more”>collapse of its magnetic field had continued. But it is almost certain that our planet would be much drier today. What to show the importance of an inner core growing to maintain a magnetic field throughout the lifetime of a planet »
concludes John Tarduno.

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