Earth’s Inner Core: Its Rotation Is Now Officially Slowing

A new study has confirmed that Earth’s inner core rotation has indeed slowed, raising questions about the central dynamics of our planet and potential impacts on us.

Researchers from the University of Southern California (USC) believe this alteration in the core’s rotation might slightly lengthen our days, though only by fractions of a second—so there’s no need to reset your watches just yet.

Puzzled by Initial Seismograms, Evidence of Change Became Irrefutable

“The initial seismograms suggesting this change left me puzzled,” says John Vidale, an Earth scientist at USC. But with over two dozen further observations showing the same trend, the evidence became irrefutable.

“This marked the first significant slowdown of the inner core in many decades. Although recent studies have proposed different models, our new research offers the most compelling resolution.”

Unraveling Earth’s Deep Mysteries

Deep within the Earth, the inner core is a blazing, ultra-dense sphere of iron and nickel, approximately two-thirds the size of the Moon. At a depth of over 3,000 miles (or just over 4,800 kilometers), it is far from easy to study. Yet, understanding it could illuminate much about Earth’s history.

Vidale and his team studied 121 recurring earthquakes recorded between 1991 and 2023 near the South Sandwich Islands in the South Atlantic, along with data from multiple nuclear tests.

Each event caused notable reverberations throughout the planet.

By observing the changes in speed and interaction of these waves, researchers can estimate the inner core’s position and motion.

Causes of the Apparent Reversal Since 2010

The core’s apparent reversal relative to the surface, which seems to have started around 2010, may result from the continuous motion of the liquid iron outer core, which generates Earth’s magnetic field, or the influence of gravitational forces.

As for what this means: it’s still uncertain. Variations in speed, reversals, and wobbles of the inner core are not uncommon, so there’s no indication that an apocalyptic event is imminent, unlike in sci-fi scenarios. Any changes in the length of days would be very slight.

“It would be very difficult to notice, likely a thousandth of a second, almost lost in the noise from the oceans and atmosphere,” Vidale points out.

The study certainly enhances our understanding of deep geological mysteries, and the inner core’s rotation will remain under close scrutiny by scientists.

“The inner core’s movements might be even more intricate than we know so far,” Vidale says.

Read the original article on: Science alert

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