PLANET EARTH
Earth’s rotating inner core is slowing down
WORDS HARRY BAKER
Decades of repeating earthquake data show that Earth’s inner core has been rotating more slowly over the last 14 years
© Alamy / Getty / Shutterstock
Did you know?
Earth’s inner core is 1,500 miles thick
The heart of our planet has been spinning unusually slowly for the past 14 years. And if this mysterious trend continues, it could potentially lengthen Earth’s days, though the effects would likely be imperceptible to us. Earth’s inner core is a roughly Moon-sized chunk of solid iron and nickel that lies more than 3,000 miles below our feet. It is surrounded by the outer core, a superhot layer of molten metals similar to those in the inner core, which is surrounded by a more solid sea of molten rock known as the mantle, and the crust. Although the entire planet rotates, the inner core can spin at a slightly different speed as the mantle and crust due to the viscosity of the outer core.