The Earth has nearly lost its magnetic field

(shoo_arts / Getty Images) It's thanks to the magnetism of the planet, combined with its rotational motion, that there is the atmosphere, layer of air that prevents us from being completely roasted by the radiations and from undergoing the influence of solar winds – charged particles that the Sun emits. Without this protective shield, the Earth would become a vast open space, as Mars, for example, is today.

Sounds like a distant scene, is not it? But very little did not happen. This is at least what researchers at the University of Rochester in the United States are advancing in a new study published in the journal Nature .

According to the group, the Earth's magnetic field was ten. lower than the current at the end of the Ediacaran period (between 630 and 542 million years ago). About 565 million years ago, however, a phenomenon prevented its definitive collapse: the solidification of magma in the Earth, which resulted in the formation of the planet's nucleus.

Previous research has always brought out the idea that the inner core of our planet would be relatively new. In the early years of the Earth, 4.5 billion years ago, its interior was essentially made up of magmatic rocks in the liquid state. However, due to the decreasing temperature of the Earth and the resulting heat loss, the layer of rock we now call the crust and mantle has increased, leaving the magma crushed deeper.

This is due to the fact that, some scientists believe that it has pbaded between 2.5 billion and 500 million years – the iron and nickel of the interior of the Earth began to cool, giving birth to the central core. The solidification of the core resulted in the expulsion of the center elements such as silica, magnesium and oxygen, creating a convection motion.

This flow of metals in the center of the planet keeps the electrically charged particles in constant motion, generating an electric current, per table, the terrestrial magnetic field. It is this movement of rocky fluids that explains the existence of magnetism to this day.

"As the Earth began to form, the energy required to maintain the convection process gradually decreased to reach the critical point of 565 million years ago, when the magnetic field had an extremely low intensity. ", said John Tarduno, co-author of the study, in an interview with Newsweek . "The growth of the inner core of the Earth provides a new source of convection and reconnects the" geodynamics "of the planet.

565 billion years ago, the natural movement of minerals at 39 Inside the Earth almost stopped, the appearance of the cooling of the nucleus gave the necessary little boost to the Earth.This restarts the system and regulates the convection movement for it to work again, shaping thus the Earth's magnetic field until it reaches its current strength.

But as you can see from an event that occurred there are nearly 600 million people in the world. years, reader, you must ask.To estimate this date, scientists badyzed particles of sand the size of a crystal, extracted from a rock located near Sept-Iles, l & # 39; Canada, Quebéc, having formed the same geological epoch. 9007] The minerals of this rock are: plagioclase (cousin of feldspar) and pyroxene (of the silicate family), even millions of years later, are therefore a means of mapping the Earth's magnetic field. In their composition, they carry iron particles in the form of a needle. Here is the key: they align on the rock a pattern that obeys the orientation of the magnetic field at the time of its formation – a complete plaque to understand the behavior of terrestrial magnetism at the time.

When badyzing samples using a device called magnetometer, used to measure the intensity, direction, and direction of magnetic fields, scientists have determined that the particle charge was very low. The researchers estimate that the strength of the Earth's magnetic field at the time would be precisely ten times lower than the current current, the lowest ever recorded by geologists over the 4.5 billion years of the Earth's history. history of the planet.

The Earth has been losing heat since. This is why, in a few billion years, the magma crust of the planet tends to become smaller and smaller by the process of cooling and solidification, disrupting the magnetic field again. That, unless another phenomenon of this kind counts for the ups and downs of the minerals of the terrestrial interior to return to the axes. As it always happens when it comes to geological scales, we should not be here to see history repeat itself, of course.