Quantum Mechanics Could Shake Up Our Understanding of Earth’s … – Gizmodo

Earths magnetic field does way more than guide our compasses and cause occasional worry. Its part of the reason theres life at all on this planetit protects us from harmful solar radiation that might otherwise blow our ozone layer away.

But theres still a lot about the magnetic field scientists dont understand. Most importantly, theyre having trouble figuring out why its so strong. One team decided to take a closer look at the role of the individual elements inside the planet that are thought to influence the field. Turns out, the way nickel behaves at the smallest scales might help explain the magnetic fields strength, to the point that some existing models would need to be rethought. And understanding the Earths magnetic field has implications for everything that relies on it, including activities that require drilling underground.

This is a new idea put into the geophysics research line that nickel has been neglected for the explanation of the geodynamo, the mechanism for creating the magnetic field, study author Giorgio Sangiovanni from the Institute for Theoretical Physics and Astrophysics at the University of Wrzburg in Germany told Gizmodo.

At its most basic level, the Earth probably gets its magnetic field from temperature gradients in the outer core causing metal to convectthis is more or less the way water moves around in a pot of boiling water. Metals can conduct electricity. So, moving metals combined with Earths rotation could create tubes of electric current that point to the poles. Loops of electric current generate magnetic fields through them, so the entire Earth ends up looking like a magnet where the poles align with the tops and bottoms of the tubes.

The problem, which people have been talking about for a while now, is that theres another way for heat to transfer between elements around the core, conduction, that doesnt require metals to physically move. In that case, the energy just gets passed between the atoms as they bump into one another, like how heat travels down the handle of the pot of water youre boiling. But if the outer core loses too much heat through conduction, then theres not enough energy to drive the convection creating the magnetic field. Scientists think that might be the case, and are looking for a source of extra energy that could generate the magnetic field they observe.

Sangiovanni and his colleagues decided to make calculations about the metals in the inner core, to see if they could find some of the missing energy. But unlike the outer core, which is mostly iron, the inner core is 20 percent nickel. The team decided to examine how nickel and irons specific quantum mechanical properties in the Earths solid core impact the magnetic field.

These properties arent fundamental enough to require you to bend over backward imagining Schrdingers cat. They describe the structure of nickel and iron atoms at high temperatures, how electrons interact in collections of these atoms, and how these elements behaviors change at high pressures. It turns out that nickels shape in a solid slows its electrons down. The electrons also interact and scatter off of each other, preventing nickel from being a good conductor of heat, according to the paper published yesterday in Nature Communications. Iron, meanwhile, has a high conductivity at the temperatures and pressures found in the inner core.

In short, the researchers think nickel could reduce the overall conductivity of the core, causing it to retain extra energy that drives convection. And this new insight might have a large enough effect that models of the Earths magnetic field need some reconsidering.

But the researchers findings cant be taken as fact yetthey still need to calculate other properties relating to how nickel conducts heat. But it is promising, said Sangiovanni. Well see after we calculate other important observables, like the thermal and electrical conductivity.

Sangiovanni said that others he spoke to were surprisedmany folks are looking at how lighter elements like silicon influence the physics of Earths core. I would say that people for a long time have discussed the possible presence of nickel in the Earths core, Dario Alf, physics professor at University College, London told Gizmodo, but no one has really discussed it in the way Giorgios paper points out, the effect of nickel on the conductivity of the core.

All that being said, just take solace in the fact that if you dont think you understand the Earths magnetic field, scientists arent completely sure how it works, either.

[Nature Communications]

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Quantum Mechanics Could Shake Up Our Understanding of Earth's ... - Gizmodo