Earth’s magnetic field is older than previously thought: Swiss scientists

The calculations by the Zurich scientists were carried out in part on the Piz Daint supercomputer in Lugano, southern Switzerland. EPA European Southern Observatory/Keystone

Scientists at the Swiss federal technology institute ETH Zurich have reconstructed the history of the Earth's magnetic field. In collaboration with a Chinese team, they show in the journal Nature that the protective magnetic field already existed more than a billion years ago, much earlier than previously thought.

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Using complex computer simulations, the authors were able to demonstrate for the first time that an entirely liquid Earth core, as it existed before the crystallisation of the inner core, could also generate a stable magnetic field.

The work was based on a model that reproduces the dynamics of the Earth’s interior under realistic physical conditions. The calculations were carried out in part on the Piz Daint supercomputer in Lugano, southern Switzerland.

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“Until now, no one had been able to carry out such calculations under such correct physical conditions,” Yufeng Lin, the lead author of the study, is quoted as saying in a press release on Thursday. In his view, the viscosity of the Earth’s core does not have a decisive influence on the processes by which the magnetic field is formed.

Protection against cosmic rays

The Earth’s magnetic field protects the planet from harmful cosmic rays and is therefore a central factor in life on Earth, both in the geological past and in modern civilisation.

According to the ETH Zurich, this new knowledge could not only help us to better understand the Earth’s ancient history, but also allow us to draw conclusions about the magnetic fields of other celestial bodies, such as the Sun or Jupiter.

In the long term, it is essential to understand the mechanisms behind the formation and modification of the Earth’s magnetic field. This is particularly important in light of recent observations, such as the rapid shift of the North Magnetic Pole towards the geographic North Pole in recent decades.

Translated from French with DeepL/gw

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