Earth’s core ‘cooling faster than thought’

The Earth may be losing its internal heat at a faster rate than previously estimated, according to scientists at the federal technology institute ETH Zurich. Researchers devised a laboratory experiment for measuring the amount of heat being radiated from the planet’s core of molten iron and nickel to the surface. The heat is conducted through a mineral in the Earth’s mantle, called bridgmanite, which comes into direct contact with the outer core. The transfer of heat powers volcanic activity and the movement of tectonic plates. The experiment employed an “optical absorption measurement system, in a diamond unit heated with a pulsed laser”, to simulate bridgmanite’s thermal conductivity at a depth of 3,000 kilometres at temperatures of up to 6,000 degrees Celsius. “This measurement system let us show that the thermal conductivity of bridgmanite is about 1.5 times higher than assumed,” said ETH Zurich professor Motohiko Murakami. “Our results could give us a new perspective on...