Scientists discover new fifth layer deep inside Earth’s core
- Researchers confirm the existence of an ‘innermost inner core’, in addition to the traditional crust, mantle, outer core and inner core
- The layer’s presence may point to an unknown, dramatic event in our planet’s history
Scientists have discovered yet another layer deep inside the core of the Earth, a new study suggests.
“Traditionally we’ve been taught the Earth has four main layers: the crust, the mantle, the outer core and the inner core,” said Australian National University geophysicist and study lead author Joanne Stephenson.
Now a team of researchers from the university has confirmed the existence of what it’s calling the Earth’s “innermost inner core”.
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To study Earth’s core, the team used a search algorithm to trawl through and match thousands of models of the inner core with observed data across many decades about how long seismic waves take to travel through the Earth, ScienceAlert reported.
By analysing how the different layers cause the sound waves to slow, scientists can catch a glimpse of what lies below, Discover magazine said.
Though this new layer is difficult to observe, its existence may point to an unknown, dramatic event in Earth’s history, according to the study.
“We found evidence that may indicate a change in the structure of iron, which suggests perhaps two separate cooling events in Earth’s history,” Stephenson said in a statement. “The details of this big event are still a bit of a mystery, but we’ve added another piece of the puzzle when it comes to our knowledge of the Earth’s inner core.”
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The idea of another distinct layer in the core has been around for a couple of decades, but the data has been unclear until now. “We got around this by using a very clever search algorithm to trawl through thousands of the models of the inner core,” Stephenson said.
She added that investigating the structure of the inner core can help us understand more about Earth’s history and evolution.
“It’s very exciting – and might mean we have to rewrite the textbooks,” she said.
The study was published in the Journal of Geophysical Research: Solid Earth, a publication of the American Geophysical Union.
