Produced by: Manoj Kumar
Earth’s day length is not fixed, fluctuating by milliseconds due to internal and external forces, scientists reveal.
New research from ETH Zürich links subtle shifts in Earth’s molten iron core to variations in its rotation.
Every thousand years, day length changes by 3-4 milliseconds, attributed to core-mantle boundary activity.
Scientists painstakingly subtracted known fluctuations, such as lunar pull and ice mass shifts, to isolate the core's impact.
Using neural networks, magnetic field data from rocks, and modern measurements, researchers traced core-driven fluctuations.
Historical data from lunar eclipses and occultations dating back to 720 BCE provided crucial insights into Earth’s rotation.
Shifts in ice and water volumes affect Earth's spin, though their impact is smaller than previously thought, says the study.
Fluid motion in Earth’s outer core, as explained by magnetohydrodynamics, aligns with millennial day-length variations.
While findings confirm the core’s role, researchers emphasize the need for better models to fully understand Earth’s rotational quirks.