The Earth's core threatens to “steal” a second of hours

An almost imperceptible change in the speed of the Earth's rotation threatens to throw off its measuring system Of time All over the world, but just for a second.

A few years from now, the planet's clocks may have to “lose” a second, as the planet begins to spin a little faster than it did before. Clocks could be required to skip one second by 2029, according to a study published in the journal Nature on Wednesday.

“This is an unprecedented situation and a big deal,” said study lead author Duncan Agnew, a geophysicist at the Scripps Institution of Oceanography at the University of California, San Diego.

“It's not a major change in the Earth's rotation that will cause some kind of catastrophe or anything, but it's a wonderful thing. This is another indication that we're in a very unusual time.”

“Brakes” at the poles

Agnew said the melting of ice at Earth's poles offsets the increase in the planet's rotation speed and is likely to delay developments by about three years.

“We're headed for one Negative againDennis McCarthy, retired director of timing systems at the US Naval Observatory, who was not involved in the study, confirms. “It's a question of when,” he adds.

It takes the Earth about 24 hours to make a complete revolution on its axis, and for thousands of years it has generally tended to slow down, explain Agnew and Judah Levine of the National Institute of Standards and Technology's Time and Frequency Division.

McCarthy points out that the slowdown is mainly due to the tidal effect caused by the Moon's pull. “Sometime between 2016 and 2017 or perhaps 2018, the rate of deceleration slowed down so much that the Earth actually started accelerating,” Levin said.

The secret of the essence

The Earth is accelerating because its hot, liquid core acts in unpredictable ways, with varying eddies and flows, Agnew said, estimating that the Earth's core has been causing an acceleration trend for about 50 years. But the rapid melting of the polar ice caps since 1990 has overshadowed this trend.

Agnew explains that melting ice transfers mass from the poles to the bulge center, slowing the planet's rotation, just as a skier slows down when she extends her arms out to the sides. Without the effect of melting ice, Earth would need this negative second in 2026 instead of 2029, according to his calculations.

McCarthy disputes that the trend necessitating the “negative second” is clear, but he thinks it has more to do with the Earth becoming rounder due to geological shifts since the end of the last ice age.

Again, Levin doesn't think a negative second will eventually be needed, insisting that the general trend of tidal slowing has been around for centuries and continues, while smaller trends in the Earth's core are transient.

“This is not a process where the past is a good basis for predictions,” he says. “Anyone who makes a long-term forecast is on very shaky ground.”

With information from the Associated Press