Researchers Confirm Earth’s Inner Core Is Solid

'We found the inner core is indeed solid, but we also found that it's softer than previously thought.' (Image: nohaggerty via Pixabay)

A new study by researchers at The Australian National University (ANU) could help us understand how our planet was formed. Associate Professor Hrvoje Tkalčić and Ph.D. Scholar Thanh-Son Phạm are confident they now have direct proof the Earth’s inner core is solid.

They came up with a way to detect shear waves, or “J waves,” in the inner core — a type of wave that can only travel through solid objects. Associate Professor Tkalčić said:

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Inner core shear waves are so tiny and feeble they can’t be observed directly. In fact, detecting them has been considered the “Holy Grail” of global seismology since scientists first predicted the inner core was solid in the 1930s and 40s. So the researchers had to come up with a creative approach.

Their so-called correlation wavefield method looks at the similarities between the signals at two receivers after a major earthquake, rather than the direct wave arrivals. A similar technique has been used by the same team to measure the thickness of the ice in Antarctica, Dr. Tkalčic said:

J waves in Earth’s inner core

The study shows these results can then be used to demonstrate the existence of J waves and infer the shear wave speed in the inner core. While this specific information about shear waves is important, Dr. Tkalčić says what this research tells us about the inner core is even more exciting:

The research has been published in Science Magazine.

Provided by: Australian National University [Note: Materials may be edited for content and length.]

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