Earth’s inner core seems to be slowing its spin – By Carolyn Y. Johnson (The Washington Post) / Jan 23, 2023
In the mid-1990s scientists found evidence that Earth’s inner core, a superheated ball of iron slightly smaller than the moon, was spinning at its own pace, just a bit faster than the rest of the planet. Now a study published in Nature Geoscience suggests that around 2009, the core slowed its rotation to whirl in sync with the surface for a time – and is now lagging behind it.
The provocative findings come after years of research and deep scientific disagreements about the core and how it influences some of the most fundamental aspects of our planet, including the length of a day and fluctuations in Earth’s magnetic field.
Three thousand miles below the surface, a scorching hot ball of solid iron floats inside a liquid outer core. Geologists believe that the energy released by the inner core causes the liquid in the outer core to move, generating electrical currents that in turn spawn a magnetic field surrounding the planet. This magnetic shielding protects organisms on the surface from the most damaging cosmic radiation.
Don’t panic. The core’s slowing down isn’t the beginning of the end times. The same thing appears to have happened in the late 1960s and early 1970s, and the study authors at Peking University in China suggest it may represent a 70-year cycle of the core’s spin speeding up and slowing down.
