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.