The Answer To Why The Earth Has A Solid Center Despite Very High Temperatures And Pressure

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Feb 15, 2017

The Earth’s center is extremely hot and the temperatures are hotter than that of the sun. Theoretically, gases and liquids exist at such high temperatures but the inner core of the Earth remains solid. Why? Scientists think that this could be due to the atomic structuring of the crystallized iron ball in the center of the Earth. They suggest that this core could be the reason why the center remains solid despite such high temperatures and pressures.

The Earth and it’s never ending mysteries

A team in Sweden from the KTH Royal Institute of Technology used ‘Triolith’ to create atmospheric processes that may be taking place in the Earth’s center, around 6,400 km below the Earth’s surface. The atomic structures of metals change with temperature and pressure. At room temperature and pressure, iron is in a body-centered cubic (BCC) phase but when exposed to high pressures it goes into a hexagonal close packed (HCP) phase. These phases or terms represent the arrangement of atoms that affect the properties of the metal.

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It was believed till now that within the Earth’s center conditions were too unstable for the BCC phase to exist and hence the iron core was in an HCP phase. According to the new research,however, the conditions at the centre don’t break the BCC arrangement but actually strengthen the arrangement. One of the researchers, Anatoly Belonoshko said, “Under conditions in Earth’s core, BCC iron exhibits a pattern of atomic diffusion never before observed.”

The interesting thing is that the instability destroys the BCC phase at lower temperatures but at higher temperatures it makes the BCC arrangement much stronger. Belonoshko used the card of decks analogy and said that like in a deck of cards being shuffled, cards are re-positioned but the deck remains intact. In the same manner the atoms are being shuffled at great speeds but the overall arrangement doesn’t change.

Scope of the research

The forces that the iron core is exposed to, so deep in the Earth include 3.5 million times the pressure we experience at the surface and temperatures of around 6000 degrees Celsius higher than those we experience. According to the data from Triolith, the core of the Earth is most probably made of 96% iron whereas the rest of the 4% is attributed to light elements like nickel.

The latest research can also solve the mystery of why seismic waves travel much faster between the poles than through the equator. This feature is referred to as ‘anisotropy’. The research suggests that the conditions in the center could create large scale anisotropic effects that can open room for more discussion and research in the future. However, it must be added that these hypotheses are based on simulations and different models.

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Till it can be figured out how to get instruments so deep within the core, we can never be entirely sure about these conclusions. The research is, however, extremely important and can help us predict various geological changes. “The ultimate goal of earth sciences is to understand the past, present and future of the Earth,” says Belonoshko, “and our prediction allows us to do just that.”