A new chapter of the Earth’s history may be about to be written after boffins discovered evidence there may be another layer at the heart of our planet – where temperatures exceed 5,000C
The story of our planet’s history is told by its layers and research suggests a new chapter may be about to be written. Boffins have found evidence that the Earth’s inner core has another smaller core within it.
Conventional knowledge suggests our planet has four main layers; the crust (where we live), the mantle, the outer core and the inner core. Scientists understand the structure of our planet by analysing the lava that comes from deep within the Earth before erupting from volcanos.
They also asses seismic waves that are generated by earthquakes and other explosive episodes. From these methods, the scientific community estimates the inner core has temperatures hotter than 5,000C and makes up 1% of the planet’s total volume.
Back in 2021, Australian National University geophysicist Joanne Stephenson and her colleagues uncovered signs the Earth’s core may have two distinct layers. She said at the time: “Traditionally we’ve been taught the Earth has four main layers: the crust, the mantle, the outer core and the inner core.
“It’s very exciting – and might mean we have to re-write the textbooks! We found evidence that may indicate a change in the structure of iron, which suggests perhaps two separate cooling events in Earth’s history.”
She added: “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.”
It comes as recent analysis of the Earth’s core suggests that over the last 15 years the centre of our planet has begun to not only slow down but also change shape. American Geophysicist John Emilio Vidale, from the University of Southern California, suggested these findings at the American Geophysical Union as scientists attempted resolve the long-standing debate on what was happening inside Earth’s core.
Due to no instruments existing capable of probing Earth’s inner layer, scientists used earthquakes that occur on the South Sandwich Island, near Antarctica which repose on the opposite side of the planet to instrument arrays in Alaska. Earthquake waves travel through the planet like sonar waves through water and some pass through the inner core on their way to Alaska.
Instruments in Alaska record the waves’ signatures called waveforms which contain information about what the waves encountered in their journey through the earth.
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