(ORDO NEWS) — New measurements of the properties of the mineral from the deep layers of the mantle have shown that the core of the planet is losing heat one and a half times more actively than previously believed.
The history of our planet is in many ways the history of cooling. Billions of years ago, the Earth was hot from the center to the surface, which remained molten.
Gradually, extreme temperatures began to persist only at depth, while the outer layers cooled and hardened. However, the cooling continues, and heat is still rising from the interior, largely determining magma flows, plate tectonics and volcanic activity.
Questions about the rate at which the earth’s interior loses heat and when it finally freezes remain debatable. To find answers, Motohiko Murakami’s team at the ETH Zurich (ETH Zurich) investigated the properties of minerals brought up from deep, from the boundary region between the mantle and the planet’s outer core.
The results of the work are presented in an article published in the journal Earth and Planetary Science Letters .
There is a large temperature difference between the lower mantle and the outer liquid core, and there must be active heat transfer. Therefore, scientists were interested in the heat-conducting properties of the main material of this layer – bridgmanite (silicate perovskite).
Under laboratory conditions, they simulated the temperatures and pressures that exist in the bowels of the planet, at a depth of hundreds of kilometers, and measured the ability of a mineral to conduct heat under such conditions.
This figure turned out to be about one and a half times higher than previously thought. Accordingly, the rate of heat loss from the Earth’s core is higher than previous estimates. Moreover, the pace will only increase: scientists have found that as it cools, bridgmanite changes its structure and begins to transfer heat even more efficiently.
As a result, the planet is cooling faster than scientists thought, approaching the (so far distant) time when the mixing of the mantle will stop and plate tectonics will stop. Once upon a time, this happened to Mars – however, due to the much smaller size of the planet, this happened much earlier.
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