The Earth's interior is cooling faster than expected

Researchers at the Swiss Federal Institute of Engineering ETH Zurich have demonstrated that a common mineral, located between the Earth's core and mantle, is a good conductor of heat. This leads them to assume that the Earth's heat is rapidly decreasing.

The evolution of the Earth is the story of its cooling. 4.5 billion years ago, the Earth was covered with molten rock (magma) deep in the ocean, creating extreme temperatures common on its surface. Over millions of years, the Earth's surface cools to form a brittle crust.

The process of measuring the Earth's heat takes place in an environment of high pressure and extreme temperature

Massive thermal energy from the Earth's interior as it moves still escapes through volcanism, mantle convection (the viscous rock layer below the crust and above the core) and plate tectonics (Earth's outer crust is divided into several parts called "tectonic plates").

However, for many years, scientists have been searching for answers to the question: How does the Earth cool down so quickly and how long does it take for this continuous cooling process to stop?

Scientists at ETH Zurich have demonstrated that the escape of heat inside the Earth's crust lies in the thermal conductivity of minerals that lie between the boundary between the core and the Earth's mantle.

This boundary layer consists of the viscous rock layer of the Earth's mantle in direct contact with the iron-nickel melting of the core layer. Between the two layers of contact there will be a lot of heat from the Earth's core escaping here.

The mineral Bridgmanite forms this boundary layer. This is a mineral that makes up the majority of the Earth, consisting of a silicate - perovskite compound (ceramic materials with a crystal structure similar to that of the calcium titanate ceramic material, CaTiO3).

However, researchers have had difficulty estimating how much heat this mineral transfers from the Earth's core to the mantle, as experimental verification is nearly impossible.

Professor Motohiko Murakami and colleagues from the Carnegie Institution for Science in Washington state (USA) have developed a sophisticated measurement system that allows them to measure the thermal conductivity of Bridgmanite in the laboratory, under pressure conditions. and the prevailing temperature inside the Earth.

"This measurement system shows us that the thermal conductivity of Bridgmanite is about 1.5 times higher than previously assumed," said Mr. Murakami. This suggests that the heat flux from the core into the mantle is also higher than previously thought.

"The results of our study may provide a new insight into the dynamic evolution of the Earth. The study suggests that Earth, like the other rocky planets Mercury and Mars, is cooling. go," Mr. Murakami explained.