Crust, mantle, outer core and inner core are the four layers that make up the innermost part of the Earth. Terre. But new research seems to indicate a greater complexity concerning the inner core, which would contain a 650 kilometer metallic sphere which would contain many secrets regarding the evolution of the planet. The discovery comes fromAustralian National University (Anu) and confirms suspicions that have arisen, and are being investigated by academics, over the past 20 years.
Researchers have studied the seismic waves that crossed the planet during recent earthquakes. After studying the effects caused by some 200 earthquakes, they seem to be able to confirm the presence of this metallic sphere, found thanks to the type of seismic wave rebound on the core found in the analysis.
If this is confirmed, new theories on the evolution of the Earth might see the light of day: concretely, two distinct layers in the inner core might have formed at two different periods of Earth’s formation.. “The inner core acts as a gateway to events from our planet’s past” said one of the researchers, Hrvoje Tkalčić.
We are talking regarding events that happened on the Earth hundreds of millions, even billions of years ago, and that it is now possible to illuminate thanks to modern technologies used to study earthquakes. The vibrations they cause, by propagating from one layer to another in the center of the Earth, provide information on the nature of the materials that make up the core. In particular, the researchers used a new technique to improve the signals recorded by seismological instruments.so that one can see the signals bouncing off the core multiple times.
By observing how these waves have been slowed down or accelerated by the material they pass through, seismologists can determine the nature of the event. material properties found at the center of the Earth. “We have a new way to probe the Earth’s inner core and its most central region. »said another of the researchers, Thanh-Son Pham.
The interesting question now How were the two layers of the inner core formed?. In fact, a very important event may have occurred which led to changes in the structure of the nucleus. “There are still many unanswered questions regarding which Earth’s innermost core might hold the secrets to piecing together the mystery of how our planet was formed. »and declared Tkalčić.
The researchers identified variations in the travel times of seismic waves in the central part of the inner core that would suggest that the structure of the innermost region of the inner core is different from that of the outer core. The core consists of a iron-nickel alloywhile the inner part would present differently organized iron crystals. For more details, we refer you to the publication in Nature.
