Unraveling Earth's Core: A Decades-Long Mystery Solved

The rotation of Earth's inner core is not aligned with the rotation of the mantle, causing a wobble that affects the motion of the poles and the length of days. The misalignment, with a tilt of 0.17 degrees, suggests a slight difference in density between the northwestern hemisphere of the inner core and the rest. Researchers discovered this through the analysis of polar motion and day-length fluctuations, indicating a periodic variation of 8.5 years. The study highlights the complexity of Earth's core-mantle system and its impact on our planet's dynamics.