Inner Core Gravity May Explain Millisecond Changes in Earth's Day
A Nature study links gravity from Earth's inner core to small variations in rotation speed, reproducing observed changes from 1964 to 2019.
Earth's day length shifts by a few milliseconds over time, and a new study in Nature suggests gravity from the inner core plays a role in those small changes. The inner core does not rotate at the same rate as the rest of the planet, and researchers modeled how its interaction affects Earth's spin.
The team reconstructed the effect on Earth's rotation from 1964 to 2019. Their model reproduced both the timing and magnitude of gradual rotation changes observed during that period, according to the study.
Mathieu Dumberry, a geophysicist at the University of Alberta, is listed among the researchers. The work points to inner core gravity as a driver of the subtle variations in day length, WIRED en Español reported.
Quick answers
What did the Nature study find about Earth's rotation?
It proposes that inner core gravity drives small changes in Earth's rotation speed and reproduced the timing and magnitude of observed gradual changes from 1964 to 2019.
Does the inner core rotate with the rest of Earth?
No. The inner core does not rotate at the same rate as the rest of the planet.