Think of the earth as a geological lollipop. If you looked more than 5,000 kilometers below your feet at the center of the planet, you would see a dense, dense ball of iron, about three-quarters the size of the moon. This iron sphere is the inner core and lies in the liquid outer core of the planet.
The inner core is always growing: its radius is increasing by a millimeter each year as molten iron pieces cool in the outer core and harden into iron crystals. Although the temperature inside the core is high enough for molten iron, the intense pressure deep within the planet keeps the crystals from melting – think of it like hitting a hard snowball.
Also read – Buried remains of ancient planets can affect Earth’s magnetic field
But according to a recent study published in the journal Natural Sciencesdevelop the inner core in an unbalanced way. The eastern half of the sphere, under the Banda Sea in Indonesia, collects 60% more iron crystals than its western half, which lies beneath Brazil. “The west side looks different from the east side to the city center,” said Daniel Frost, a seismologist at the University of California at Berkeley. He co-authored the new study in a statement. “The only way to explain this phenomenon is for one side to grow faster than the other.”
Asymmetrical growth in the nucleus
Although Earth is more than 4 billion years old, its inner core is younger – according to geologists, it formed between half a billion and 1.5 billion years ago when pieces of molten iron began to crystallize from the outer core. Daniel Frost’s team has created computer models that have followed the growth of the deep core over the last billion years. They found that the asymmetrical nature of the nucleus probably started soon after it was formed.
Of course, if one half has grown faster than the other for a long time, the shape of the inner core should no longer be round. However, this did not happen. Therefore Daniel Frost and his colleagues 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 nucleus to maintain its spherical shape.
Daniel Frost’s team doesn’t know exactly why iron crystals form unevenly on the inside, but he says the answer may be found in the upper layers — both the outer core and the mantle, a hot rock nearly 2,900 kilometers thick above. which tectonic plates float.
“Each layer of the earth is controlled by what is above it and affects what is below it,” Daniel Frost told WordsSideKick. If the iron crystallizes faster on one side of the inner core than on the other, it means that the outer core is cooling faster on the other side. Therefore, the mantle on this side must cool the outer core faster than the mantle on the other side.
According to Daniel Frost, the origin of this cooling chain could be from the Earth’s tectonic plates. If one plate presses against another, it sinks one under the other, this is a phenomenon of subduction. The descending plate cools the mantle in this area of the planet.
Asymmetrical nuclear growth can affect Earth’s magnetic field
The Earth’s core plays an important role in protecting the planet from harmful winds and solar radiation. The rotating iron in the outer core generates a magnetic field that extends from there into the space around our planet. These eddies are caused in part by a process in which warmer, lighter outer core material rises into the overlying mantle. There it is replaced by cooler, denser mantle material that sinks into the lower core. This is called convection.
Convection also occurs between the inner core and the outer core. If different parts of the outer core and inner core cool at different speeds, it can affect the amount of heat exchanged at the boundary, which can affect the rotating motor that drives the earth shield.
“The question is whether it will change the strength of the magnetic field,” Daniel Frost told WordsSideKick. For now, the group isn’t sure, but Daniel Frost says he’s studying the answer.
Original version: Aylin Woodward / Insider
Also read – Earth’s axis is moving faster due to climate change, research finds
–
