Unlike the concern raised by global warming, which could cause a climate “apartheid” in the future, the thermal evolution of the Earth’s core could be oriented towards faster cooling than ever before.
Our planet, since its constitution, has faced a constant cooling process that has led to the generation of the earth’s crust and the formation of life. In this sense, research conducted by a team of researchers from the Zurich ETH has set its goal in understanding whether this thermal process has happened in a similar way in the Earth’s core. The study used the thermal conductivity analysis of the minerals at the boundary between the earth’s nucleus and the mantle, with an extremely sophisticated measurement of bridgmanite, an iron-magnesium silicate forming this ‘limite’ layer.
The research group, led by Professor Motohiko Murakami, irradiated a single bridgmanite crystal with laser buttons, highlighting that its thermal conductivity level is at least 1.5 times higher than previously assumed. It follows that the heat flow, and therefore its dispersion, in the boundary area between the outer nucleus and the mantle is larger and faster than was thought. This rapid cooling transforms the same bridgmanite into a post-perovskite mineral, promoting a potential increase in the speed of cooling of the mantle. “Our results could give us a new perspective on the evolution of Earth’s dynamics,” said Murakami. “They suggest that Earth, like other rocky planets Mercury and Mars, is cooling down and becoming inactive much faster than expected.”
However, as the researcher himself points out, we must not be overly concerned about this phenomenon because of the different variables involved. Among these we find, for example, the radioactive decay of the various elements present in the earth’s crust, which autonomously constitutes a source of heat for the planet. In this regard, it is difficult to assume when cooling causes the inactivity of the nucleus, which, among other things, guarantees the presence of the Earth’s magnetic field. In this subject you can read our article on what would happen if the Earth’s magnetic field vanished.