Earth's core might be cooling faster than anticipated, study reveals. Read here

Earth’s heat may dissipate sooner than previously thought, researchers at ETH Zurich have found in a study recently.

ETH Professor Motohiko Murakami and his colleagues from Carnegie Institution for Science have developed a measuring system that enables them to measure the thermal conductivity of bridgmanite in the laboratory, under the pressure and temperature conditions that prevail inside the Earth, said the study.

The paper was recently published in Earth and Planetary Science Letters adds that this cooling can weaken many tectonic activities.

The evolution of the Earth is a story of its cooling. According to the study, 4.5 billion years ago, the surface of young Earth was covered by magma and over the years, the planet’s surface has cooled to form the outer crust.

The researchers also mentioned that the enormous thermal energy emanating from the Earth’s interior set dynamic processes in motion, such as mantle convection, plate tectonics and volcanism.

This said, the researchers are yet to discover the rate at which Earth's core is cooling and if the core will cool down completely. 

The researchers at ETH Zurich have studied a mineral commonly found at between the core and mantle layer of Earth's interior, known as bridgmanite.

“This boundary layer is relevant because it is here that the viscous rock of the Earth’s mantle is in direct contact with the hot iron-​nickel melt of the planet’s outer core. The temperature gradient between the two layers is very steep, so there is potentially a lot of heat flowing here. The boundary layer is formed mainly of the mineral bridgmanite. However, researchers have a hard time estimating how much heat this mineral conducts from the Earth’s core to the mantle because experimental verification is very difficult,” the study reads.

The international team measured the radioactive thermal conductivity of bridgmanite in the laboratory. The core-mantle boundary of Earth is rich in bridgmanite.

"This measurement system let us show that the thermal conductivity of bridgmanite is about 1.5 times higher than assumed,” Murakami says. This suggests that the heat flow from the core into the mantle is also higher than previously thought.

“Our results could give us a new perspective on the evolution of the Earth’s dynamics. They suggest that Earth, like the other rocky planets Mercury and Mars, is cooling and becoming inactive much faster than expected,” Murakami explains.

The results showed that the thermal conductivity of bridgmanite was about 1.5 times higher than assumed. These findings also suggest that other rocky planets may be cooling and becoming inactive faster than expected.

However, he adds that it is challenging to track how long it will take for the cooling to happen which will ultimately stop the convection currents in the mantle.