Scientists have finally confirmed the theory that the Earth has a solid core after uncertainty lingered over the topic for more than 80 years.
The issue has finally been put to bed by re-purposing a technique that was first used to measure the thickness of the Antarctic ice sheet.
Researchers built a ‘fingerprint’ of our planet from the echoes of earthquakes and found that the innermost region of the planet is indeed solid.
Associate Professor Hrvoje Tkalčić from the Australia National University (ANU) studied shear waves, or ‘J waves’, in the Earth’s inner core.J waves are produced by earthquakes and only travel through solid objects.
Inner shear waves can not be directly observed as they are of such little energy so the researchers looked for a creative way to detect them.
To do this they looked at the similarities between the signals received at different locations after major earthquakes.
A version of this method has been used to calculate the thickness of the ice-shelf in Antarctica.
The Researchers then turned their method in a way that helps them understand the Earth’s innermost secrets. ‘We’re throwing away the first three hours of the earthquake and what we’re looking at is between 3 and 10 hours after a large earthquake happens,’ Dr. Tkalčic said.
These earthquake ‘echoes’ were compared to many others from different readings of the same earthquakes and this produced a ‘fingerprint of the Earth’.
Dr. Tkalčic continued his explanation by saying ‘The inner core is indeed solid and it is like the inner core of a time capsule, if we understand it we’ll understand how the planet was formed, and how it evolves.’
Source: Daily Mail