GoKawiilStudy links Earth's inner core gravity to decade-scale day-length shifts
Researchers analyzed length-of-day (LOD) records from 1964 to 2019, after removing known effects from the atmosphere, oceans, tides and surface mass changes, to isolate multidecadal variations. They modeled these residual variations using torque equations that account for gravitational pull from the inner core alongside electromagnetic and topographic coupling at the core-mantle boundary, finding that gravitational torque from the inner core contributes to the slow, multidecadal changes in how long a day lasts.
GoKawiil's interpretation of the reporting above, not reported fact.
The findings could refine scientific understanding of how Earth's deep interior, particularly the shifting position of the solid inner core, subtly influences planetary rotation over decades. This may help scientists better separate natural internal Earth processes from other influences on day-length variability, though the researchers frame their conclusions as model-based inference rather than direct observation of the inner core's behavior.
- The study examines length-of-day changes from 1964-2019 after filtering out atmospheric, oceanic and tidal effects.
- Gravitational torque from the inner core is modeled as a contributor to multidecadal Earth rotation variability.
- The approach combines core-mantle boundary coupling forces with inner-core gravitational effects to explain observed rotation changes.
Source: nature.com — Zhang, 2026-09-23
Published there as: “Gravitational torque drives multidecadal variations in length of day”
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