You may have heard that the Earth spins so fast, if it were to slow down, we’d all fall off. That’s not only false according to a new study, but the Earth’s inner core appears to have recently slowed its spin, appearing from Earth’s surface that it’s reversing.

Scientists from Peking University in China have been tracking the movements of our planet’s layers using data on seismic waves from earthquakes. They started collecting changes in these waves in the early 1960s.

Despite such research, Earth’s inner workings remain mysterious and debatable. It’s made up of four primary layers: the outer crust, the mantle, the liquid metal outer core, and the inner core made of iron and nickel. Because the inner core is separated from the rest of Earth by the liquid outer core, it’s able to rotate at different speeds relative to those on the surface.

Scientists have different theories about how the inner core moves. Last year, research suggested that the speed of Earth’s inner core rotation oscillates, gently swaying and swirling from one direction to another in a cycle.

“From our findings, we can see the Earth’s surface shifts compared to its inner core, as people have asserted for 20 years,” John E. Vidale, study co-author and Dean’s Professor of Earth Sciences at USC Dornsife College of Letters, Arts and Sciences, said in a statement. “However, our latest observations show that the inner core spun slightly slower from 1969-71 and then moved the other direction from 1971-74.”

Up on the surface, we’re hardly aware of the Earth’s core movements. However, they affect magnetic fields, causing the North Magnetic Pole to move approximately 1,200 east since the early 19th century. That, and we’ve managed to stay upright despite slower spinning speeds.