Sharjah24 – Reuters: Earth’s inner core grows 1 millimeter in radius per year, but its east side, beneath Indonesia, is growing faster than its west, beneath Brazil, because it is cooling at a faster rate, causing more iron crystals to form, according to a study in Nature Geoscience.”
“The Conversation explains that when Earth was formed a lot of heat was captured within the planet, and as this has slowly escaped, the inner core’s temperature has dropped below the melting point of iron, causing the formation of the crystals.”
“Because of lower temperatures around the east side, iron crystals form more quickly. However, Earth’s spherical shape is maintained by constant spinning and the force of gravity, which redistribute the extra mass evenly, according to Popular Mechanics.”
“To establish the disparity, scientists combined the fact that seismic waves travel much faster from north to south through the core than from side to side, with estimates of how iron alloys behave at high pressure, according to The Conversation.”
“Popular Mechanics attributes the disparity to Indonesia being covered by a mix of islands and expansive sea floor, which is a key place for heat to be shed. The study’s lead author said cold tectonic plates diving below Earth's surface may be a cause.”
“Heat loss in Earth’s inner core is important because it drives the flow of liquid iron in the outer core, which in turn creates Earth’s magnetic field. According to The Conversation, in billions of years, cooling will lead to the whole core to become solid, which will leave Earth without its protective magnetic field and leave us exposed to solar and cosmic radiation.”
“One question the study brings up is if lopsided cooling in the core could already be affecting the strength of Earth's magnetic field. We already know from the ESA that Earth’s magnetic field has lost nine percent of its strength over the last two centuries.”
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