Scientists recently discovered that Earth‘s inner core, which was long regarded as an unmoving ball of solid metal, is perhaps lots less rigid than we expected. Now, a brand new study suggests this surprising softness could also be brought on by hyperactive atoms that move around inside their molecular structure far more than we realized.
The inner core is a large spherical lump of metal, predominantly iron, that spans roughly 760 miles (1,220 kilometers) and dates back to no less than 1 billion years ago. The inner core is enveloped by the outer core — a sea of swirling liquid metals — that’s in turn surrounded by a large layer of molten rock, referred to as the mantle, which sits slightly below the solid crust we live to tell the tale.
The pressure at the guts of our planet is immense, so experts initially believed the core have to be completely solid and that the iron atoms inside it, that are arranged in a large hexagonal lattice, have to be permanently held in place.
Related: Earth’s inner core could also be slowing down in comparison with the remaining of the planet
But in 2021, seismic waves from earthquakes revealed that there have been numerous inconsistencies inside the inner core, which led some scientists to explain it as a “mushy hidden world.” Subsequent studies suggested this could also be brought on by swirls of liquid iron being trapped contained in the core or that the core exists in a “superionic state,” where atoms from other elements like carbon and hydrogen are continuously sloshing through the core’s massive lattice of iron atoms.
The brand new study, published Oct. 2 within the journal Earth, Atmospheric and Planetary Sciences, provides an alternate explanation for what is occurring contained in the inner core.
The researchers recreated the extraordinary pressure inside the inner core within the lab and observed how the iron atoms behaved under these conditions. The scientists then fed this data right into a computer-learning program to create a simulated virtual core that they dubbed the “supercell.” Using the supercell, the team was in a position to see how the iron atoms moved inside their supposedly rigid structure.
The outcomes suggest the atoms contained in the inner core can “move far more than we ever imagined,” study co-author Jung-Fu Lin, a geophysicist on the University of Texas at Austin, said in a statement.
The supercell simulations show that a few of these atoms can move around in groups, taking on other positions within the lattice without compromising its overall shape — type of like how dinner guests change seats at a table without adding or removing chairs, researchers wrote within the statement. This kind of movement is referred to as “collective motion.”
“This increased movement makes the inner core less rigid [and] weaker against shear forces,” Lin said. This might explain why the inner core is “surprisingly soft,” he added.
The researchers consider that the brand new findings could also reveal recent insights into other inner core mysteries, like the way it helps to generate Earth’s magnetic field.
“Now, we all know concerning the fundamental mechanism that may help us with understanding the dynamic processes and evolution of the Earth’s inner core,” Lin said.