Newer info related to leap second distribution and occurrences. Earth’s core has slowed so much it’s moving backward, scientists confirm: https://www.cnn.com/2024/07/05/science/earth-inner-core-rotation-slowdown-cy... Inner core backtracking by seismic waveform change reversals: https://www.nature.com/articles/s41586-024-07536-4 TL;DR: Seismologists confirm ~70 year inner core oscillation cycle. Inner core rotated eastward faster than the planet 2003-2008 and back ~ 2.5* more slowly westward 2008-2023 over the same path relative to the mantle. Mantle density anomalies and mantle and core boundary topography gravitational coupling could explain LoD Length of Day SYO 6 Year Oscillation. Slower core spin, speeds up the mantle, the planet rotates faster, and the LoD shortens by ms. Core rotation should speed up again in 5-10 years if model is confirmed. -- Take care. Thanks, Brian Inglis Calgary, Alberta, Canada La perfection est atteinte Perfection is achieved non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add mais lorsqu'il n'y a plus rien à retirer but when there is no more to cut -- Antoine de Saint-Exupéry