The Washington PostThe Washington Post

Earth's inner core seems to be slowing its spin

By Carolyn Y. Johnson

23 Jan 2023 · 4 min read

Editor's Note

The Earth’s inner core is a superheated ball of iron that spins. That spinning is now slowing, and scientists are at odds over what this exactly means for the planet. The Washington Post reports.

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.

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