- Day length drifts by a few milliseconds over decades, scientists say
- Gravity between the inner core and the mantle is the main driver, the study finds
- Electromagnetic and topographic forces push the other way, like a tug-of-war
Earth’s core is quietly changing the length of your day, study finds
A new Nature study says a gravitational tug-of-war between Earth's inner core and mantle drives tiny, decades-long shifts in the length of a day.
A day lasts 24 hours, right? Almost. Earth's spin is not perfectly steady, and a new study helps explain why. Scientists have long known that the length of a day drifts by a few milliseconds over decades. Geophysicists track this by measuring Earth's position against distant objects in space. The changes are far too small for you to notice, but…