Study links Earth's day-length changes to core-mantle torque forces

A study published in Nature reports that small variations in the length of Earth's day, on the order of milliseconds over decades, can be explained by competing gravitational, mechanical and electromagnetic forces between Earth's solid inner core, molten outer core and rocky mantle. Researchers, including geophysicist Mathieu Dumberry, had long suspected core-mantle interactions caused these fluctuations but lacked clarity on which specific forces were responsible.