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Earth’s inner core is destabilized

06/09/2021 at 1:30 PM CEST

For unknown reasons, the inner core of Earth’s iron has grown faster on one side than the other: something in the outer core or mantle of the Earth in Indonesia dissipates heat from the inner core faster than in the opposite direction under Brazil. , according to research by scientists at the University of California at Berkeley.

The cooling accelerates the crystallization of the iron and the growth of the inner core on this side. According to a press release, this has implications for the Earth’s magnetic field, which protects us from dangerous particles from the Sun. The new study was recently published in the journal Nature Geoscience.

The inner core of the Earth It is a solid sphere of iron and nickel with a radius equivalent to 20% of the total of the planet. It works like the deepest geological layer on Earth: as if it were an onion, from the surface of the planet different layers are superimposed until reaching the deepest, which is precisely its inner core.

As there are no direct samples from this part of our planet, it is possible to analyze it only through the study of the Earth’s magnetic field or seismic waves. Now, the American seismologists in charge of the new study have discovered a phenomenon that causes a more pronounced growth of one side of the Earth’s inner core over the other, generating a destabilization.

Growth imbalance

As explained in the research, the solid core of the interior is growing faster under Indonesia than on the side below Brazil. This would indicate that the molten part of the outer core of the Earth, which is falling inwards as it solidifies, would not be doing so in a homogeneous way as was thought until today: the cooling rate and heat release from the inner core would be different for each sector.

To avoid an even greater imbalance, the force of gravity comes into play: new iron crystals oriented towards the north and south poles are created to reduce the increase in asymmetries. Thanks to this, the inner core of the Earth preserves its spherical shape.

But the problem does not end here, because the solidity of the inner core and its capacity to release heat are what has allowed the Earth to have a magnetic field that protects it from dangerous solar fumes, as well as other possible consequences related to violent variations in space weather.

Related Topic: The Earth’s Core Is Accelerating.

The mystery to be solved

Why does heat dissipate unevenly from the inner core of the Earth? What are the causes of the disproportion shown according to each area of ​​the globe? The researchers will now seek to answer these questions and try to understand a phenomenon that could put the Earth’s magnetic field at risk and, consequently, leave the planet unprotected against possible attacks from space.

In addition, the study has implications for different discussions about the origin of the Earth’s magnetic field and the precise geological age of Earth’s inner core, which would be between 500 and 1.5 billion years old. Some discoveries could change the established notions in this regard and thus explain the causes of the strange phenomenon of asymmetry in the growth of the inner nucleus.

Reference

Dynamic history of the inner core constrained by seismic anisotropy. Frost, DA, Lasbleis, M., Chandler, B. et al. Nature Geoscience (2021) .DOI: https: //doi.org/10.1038/s41561-021-00761-w

Photo: The cut-out of the interior of the Earth shows the inner solid iron core (red) slowly growing by freezing the outer liquid iron core (orange). Seismic waves travel through Earth’s inner core faster between the north and south poles (blue arrows) than through the equator (green arrow). Credit: Daniel Frost.

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