The inner core of the Earth is solid but softer than previously thought | Technology and science | Science

The inner core of the Earth is solid but softer than previously thought according to a recently published study in Australia that wants to help understand how our planet was formed.

Seismological expert Hrvoje Tkalcic and doctoral candidate Than-Son Pham, of the Australian National University (ANU), were able to detect calls J waves or waves of Osborn in the inner core of the Earth, which move only toward "If our results are accurate, it turns out that the inner nucleus shares some similar elastic properties with gold and platinum "said Tklacic in a statement from the ANU.

"The nucleus of the Earth is like a time capsule, and if we understand it well, we will understand how the planet was formed and how it evolved."

The J waves of the inner core of the Earth are even tiny and weak, which can not be observed directly, so that being able to detect them has always been a challenge for seismologists since that scientists declared for the first time in the 1930s and 1940s that it was solid .

In an attempt to detect them, scientists have applied the so-called wave field correlation method which observes the similarities between the signals arriving at two different receivers after a powerful earthquake instead of observing the waves. arrive directly.

This is a technique that the same team used to measure the thickness of the ice cap in Antarctica.

"We threw the first three hours of the seismograph and focused on what happened between three hours and ten hours after an earthquake, and we wanted to avoid the most important signals," he said. scientist.

Scientists, who work with a global network of stations, compared the seismic observations of each pair of observatories for each major earthquake in order to detect their similarities.

From these similarities, we construct an overall correlogram, that is to say a kind of fingerprint of the Earth, "said the expert.

The research, published in the journal Science Magazine, can serve to demonstrate the existence of J waves and deduce the speed of shear waves, also called shear waves or S waves, in the inner core of the Earth, which holds many mysteries.

"For example we still do not know what is the exact temperature in the inner core of the Earth or its age or rapidity of solidification, but with these new advances in global seismology, we can achieve this, "said the seismologist. [19659002] Tklacic He emphasized that the understanding of the Earth's core had direct consequences on the generation and maintenance of geomagnetic fields because without them, there would be no life on the surface of the Planet, adds the release.

In 2015, scientists at the University of Illinois (United States) and Nanjing (China) developed studies suggesting that the inner core of the Earth contains different alignment crystals, formed under different conditions, and that the planet could have undergone a dramatic change during this period.

The central sphere of the Earth, which extends over more than 5,000 kilometers, began to solidify about a billion years ago and continues to grow about 0, 5 millimeters a year.

Source: EFE