A new study has found that the Earth's core is cooling at a faster pace than scientists had previously estimated. A team of researchers from ETH Zurich studied the thermal conductivity of bridgmanite, a common mineral found between the Earth’s core, and mantle.
"We found the bulk thermal conductivity at core-mantle boundary becomes ∼1.5 times higher than the conventionally assumed value, which supports higher heat flow from core, hence more vigorous mantle convection than expected. Results suggest the mantle is much more efficiently cooled, which would ultimately weaken many tectonic activities driven by the mantle convection more rapidly than expected from conventionally believed thermal conduction behavior," the researchers explained in the journal Earth and Planetary Science Letters.
The discovery raises new questions about how much the Earth's core has cooled since the planet formed billions of years ago and how long until the core becomes inactive.
"Our results could give us a new perspective on the evolution of the Earth’s dynamics," ETH Zurich professor Motohiko Murakami, the lead author of the study, said in a press release. "They suggest that Earth, like the other rocky planets Mercury and Mars, is cooling and becoming inactive much faster than expected."
While the finding doesn't have any ramifications in the near or distant future, it could shed some light on when the Earth's core will become inactive.
Once the Earth's core cools down, the planet will lose its magnetic shield, which protects the surface from harmful solar radiation. Without the shield, life on Earth will die out, turning the planet into a lifeless rock. Scientists estimate that won't happen for another 1.75 to 3.25 billion years.