Earth’s core is out of balance and growing faster under Indonesia than in Brazil

Think of Earth as a geological tootsie pop.

If you examine the center of the planet more than 3,000 miles below your feet, you will see a solid, solid iron ball about three -quarters the size of the moon. This ball of iron is the inner core, and is located inside the molten outer core of the planet.

The inner core continues to grow: its radius increases by a millimeter each year as the molten iron chips in the outer core cool and harden into iron crystals. Although the temperature in the inner core is high enough to melt iron, the intense pressure deep within the planet keeps the crystals from melting – think of it as a hard snowball.

But according to a recent study published in the journal Nature Geoscience, the inner core develops disproportionately. The eastern half of the sphere, the eastern part under the Banda Sea in Indonesia, contains 60% more iron crystals than the western half, which lies beneath Brazil.

“The west side is different from the east side to the center,” said Daniel Frost, a seismologist at the University of California at Berkeley, a co-author of the new study. in press release siaran. “The only way to explain this is that one side is growing faster than the other.”

Asymmetrical growth in the heart

Although Earth is more than 4 billion years old, its inner core is younger – geologists suspect that it formed between half a billion and 1.5 billion years ago, when chunks of molten iron from the outer core began to crystallize.

The Frost team created computer models that have followed the growth of the core in the last billion years. They found that the unbalanced nature probably started as soon as the nucleus formed.

Of course, if one half had grown faster than the other during that time, the shape of the inner core should no longer be round. But this is not the case. Frost and his colleagues therefore believe that gravity can compensate for the asymmetrical growth by pushing excess crystals from the east side of the nucleus to the west side, thereby helping the core to maintain its spherical physique.

Frost’s team isn’t sure why iron crystals form unevenly in the inner core, but he says the answer likely lies in the layers above — both the outer core and the mantle, a 1,800-mile-thick piece of hot rock on which tectonic plates float.

“Each layer of the Earth is controlled by what is above it and affects what is below it,” Frost said. Live Science word.

If the iron crystallizes faster on one side of the inner core than on the other, it must mean that the outer core is cooling faster on that side. So the mantle on this side, in turn, has to cool the outer core faster than the mantle on the other side.

The origin of this cooling chain, Frost said, could be from Earth’s tectonic plates. When one plate pushes against another, one sinks or sinks under the other. The subducting plate cools the mantle in this region of the planet.

Unbalanced core growth can have an impact on the earth’s magnetic field

The Earth’s core plays a key role in protecting the planet from wind and harmful solar radiation. circling iron in outer core inti generate a magnetic field that extends from there into the space around our planet.

These eddies occur, in part, because of the process by which warmer, lighter material from the outer core rises into the overlying mantle. There, it is displaced by cooler, denser mantle material, which sinks into the core below. This is called convection.

Convection also occurs between the inner and outer core, so if different parts of the outer core and inner core cool at different rates, it can affect the amount of heat exchanged at the boundary – which can impact the rotation of the motor that powers it. earth. sheath.

“The question is, does this change the strength of the magnetic field?” Gel Live Science word.

At the moment, the group isn’t sure, but Frost says he’s investigating the response.

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