A kind of snow cover of iron particles has been hypothesized around the hot core of the Earth in a new study appeared on JGR Solid Earth and carried out by a team of researchers led by Jung-Fu Lin, professor at the Jackson School of Geosciences of the University of Texas at Austin. According to the researchers, around the inner core of the Earth, in an environment where there is immense pressure, there would be a precipitation of tiny iron particles falling from the molten outer core accumulating over the inner core. These particles create batteries up to 200 miles thick.
According to the researchers themselves, the way this sort of semi-liquid section is formed around the inner core is similar to the way rocks are formed inside volcanoes. Jung-Fu Lin himself explains: “The metal core of the Earth functions as a magma chamber that we know best in the crust.
These are theoretical insights simply because the Earth’s core cannot be sampled or studied directly. The only way scientists can find information about this hidden section of our planet is to record and analyze the signals of seismic waves as they travel across the Earth. However, some recent studies have raised questions: these waves move slower than expected when they pass through the base of the outer core and move faster when they pass through the eastern hemisphere of the upper inner core.
To explain this phenomenon, Jung-Fu Lin and the other main author of the study, Youjun Zhang, a professor at the University of Sichuan in China, proposed this theory that the iron “snow” covered core would explain these aberrations. It is a theory in some ways already proposed in the 1960s by the scientist S.I. Braginskii according to which there was a layer of slurry between the inner and outer nucleus.
The new data collected for this study show that a sort of crystallization effect is possible in this area and that about 15% of the lower external nucleus can actually be made of iron-based crystals that eventually fall on the solid internal nucleus. “It’s kind of a weird thing to think about,” admits Nick Dygert, a professor at the University of Tennessee who participated in the study. “You have crystals inside the outer core that snow on the inner core over a distance of several hundred miles.” Among other things, this theory supports the idea that the boundary of the inner core is not represented by a simple and smooth surface, as Zhang himself explains.