GoKawiilStudy: Inner core's gravity pull tied to Earth's shifting day length
Researchers publishing in Nature propose that gravitational interactions between Earth's inner core and mantle help explain decades-long changes in the length of a day. Because the inner core rotates at a slightly different rate than the rest of the planet, it becomes misaligned with mass irregularities in the mantle, and the resulting gravitational pull works against other core-mantle interactions. Geophysicist Mathieu Dumberry and colleagues say this tug-of-war produces small accelerations and decelerations in Earth's spin over time.
GoKawiil's interpretation of the reporting above, not reported fact.
The finding could fill a long-standing gap in understanding how forces deep in the liquid outer core get transmitted to the rest of the planet, since friction alone was known to be too weak. If confirmed, this mechanism would give scientists a clearer model for predicting long-term shifts in day length, which matters for precise timekeeping and satellite navigation systems that depend on Earth's rotation rate.
- Day length varies by milliseconds due to multiple factors including atmosphere, oceans, earthquakes and ice melt.
- A new Nature study points to gravitational interaction between the misaligned inner core and mantle as a decades-scale driver.
- The mechanism could explain how forces from Earth's deep interior are transmitted outward despite weak core-mantle friction.
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Published there as: “A Gravitational Battle Within the Earth Is Changing the Length of Days”
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