GoKawiilStudy links decades-long shifts in Earth's day length to inner core gravity
Researchers Hao Zhang and Mathieu Dumberry report in Nature that gravitational coupling between Earth's solid inner core and its mantle explains multidecadal changes in day length of a few milliseconds. They combined seismological data on inner-core rotation with a model of outer-core flow derived from magnetic field measurements to reach this conclusion.
GoKawiil's interpretation of the reporting above, not reported fact.
The finding could resolve long-standing uncertainty about which mechanism drives angular momentum exchange between Earth's core and mantle, since several competing explanations had previously been proposed. Better understanding of these dynamics may help refine models of Earth's rotation, magnetic field evolution, and deep interior structure.
- New Nature study attributes decadal day-length variation to gravitational coupling between inner core and mantle.
- Method combined seismological rotation data with magnetic-field-based flow modeling.
- Findings could help settle debate among competing theories of core-mantle angular momentum transfer.
Source: nature.com — Jault, 2026-09-23
Published there as: “Gravitational forces inside Earth drag some decades out — and make others fly by”
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