Crust, mantle, outer core and inner core. These are the layers of the Earth that we have all learned in school. However, new research by a team of scientists from the Australian National University (Australia) affirms that, as if it were a Russian doll or we were going back to a novel worthy of Jules Verne himself, the inner core has another core hidden inside.
The researcher states that although this new layer is difficult to observe, its distinctive properties may point to a dramatic and unknown event in Earth’s history.
This is not a new hypothesis. In fact, the idea of the presence of a distinct layer in the Earth’s core was initially proposed a couple of decades ago, but the data was never entirely clear. “We solved this by using a very clever search algorithm to crawl thousands of models of the inner core,” Stephenson clarifies.
Thus, the experts used a search algorithm to track and match thousands of models of the inner core with data observed over many decades on how long it takes for seismic waves to travel through the Earth, compiled by the International Seismological Center.
One inner core, two layers
The inner core of iron and nickel is almost as hot as the surface of the Sun (exceeds 5,000 ° C), with a radius of about three-quarters that of the moon, and is located about 6,400 to 5,180 kilometers below the surface of the Earth rotating faster than the rest of the planet. The pressures in the core are more than 3 million times greater than at the surface of the Earth and constitute 1% of the total volume of the planet.
Previous research indicated that this other deeper inner core appears to occupy half the diameter of the general inner core and has iron crystals that point in an east-west direction, unlike the outer inner core, whose crystals point north to west. south, something that puzzles scientists.
Consistent data
“We found evidence that may indicate a change in the structure of iron, suggesting perhaps two separate cooling events in Earth’s history, ” explains Joanne Stephenson, study leader in the Journal of Geophysical Research. “The details of this great event are still a bit mysterious, but we have added another piece of the puzzle when it comes to our knowledge of the inner core of the Earth.”
These new findings could explain why some experimental evidence has been inconsistent with our current models of Earth’s structure. It is clear that it could have some important implications for us, among other things, we would have to rewrite the textbooks we study in schools …
Referencia: J. Stephenson et al. Evidence for the Innermost Inner Core: Robust Parameter Search for Radially Varying Anisotropy Using the Neighborhood Algorithm, Journal of Geophysical Research: Solid Earth (2020). DOI: 10.1029/2020JB020545
