The Earth is spinning so fast — the consequences of timekeeping could be unprecedented

our house The planet is in a hurry. On June 29, 2022, Earth completed the shortest day since scientists began keeping records in the 1960s, making a full rotation 1.59 milliseconds faster than usual.

Rushing to the ground is a trend. In 2020, the planet had its shortest 28 days on record, and it continued to spin rapidly until 2021 and 2022. Before scientists could even verify that record day of June 29, our world had almost outgrown itself: It was on fire until July 26, 2022 , 1.50 ms ahead of time.

We’re likely to see more short days as the Earth continues to accelerate, says Judah Levine, a professor at the University of Colorado Boulder and a long-time expert at the National Institute of Standards and Technology (NIST). He says shortening Earth days is not a cause for concern, because the actual time difference is down to milliseconds throughout the year. But the strange thing is that while scientists know that changes in the Earth’s inner and outer layers, oceans, tides, and climate can affect how fast it spins, they don’t know what’s driving the current acceleration.

no one is perfect – Not even our planet. On average, the Earth rotates on its axis every 24 hours, or every 86,400 seconds. But for various reasons, from the imperfect shape of the planet to its complex interior, each day is not quite the same length as the previous one.

Moreover, a day lasting exactly 24 hours is just a benchmark we expect Immediately. The Earth’s long-term rotation is slowing down thanks to the moon’s pulling back on our world. Only a few hundred million years ago, for example, Earth’s day was only 22 hours long. In the next millennia, Earth Day will last much longer.

So what results from the shorter late days, which go against the long-term trend? One hypothesis that has been put forward so far has to do with “Chandler’s wobble”. Discovered in the 19th century, this phenomenon explains how a not perfectly round Earth oscillates slightly, like a rotating top as it slows down. Leonid Zotov told that the oscillation mysteriously disappeared between 2017 and 2020, which could help Earth end the day a little faster.

Another idea is that climate change may affect how quickly the planet rotates. When ocean glaciers melt, the shape of the land changes slightly, becoming flatter at the poles and bulging at the equator. But Levine says this effect cannot explain why the planet suddenly rotates faster because melting glaciers should have the opposite effect: The planet’s moment of inertia will increase, which will slow us down.

For Levine, the likely culprit is a more mundane one.

“One possibility is the exchange of momentum between the Earth and the atmosphere,” he says. The sum of these two numbers is constant, which means, for example, if the atmosphere slows down, the Earth is accelerating. Or, conversely, if the velocity of the atmosphere accelerates, then the Earth slows down. ”

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The same thing could happen deep in our world: the deep core and the mantle – the large layer between the core and the surface – could move at slightly different speeds. There may be an exchange of angular momentum between the Earth’s deep core and the mantle, it is speculated.

“Both of these effects … can pump velocity into the Earth’s surface, or out from the Earth’s surface,” Levine says. But the dynamics of the atmosphere and the interior of the Earth are so complex that it is impossible, at least for the time being, to point to one of these factors as the sure cause of the fast pace of the planet.

Nature does not always abide To the hardness of a watch or calendar, planetary time regulators have made some adjustments. A leap year exists, for example, because we need an extra day every four years to keep the 365-day calendar in sync with the Earth’s revolution around the sun. As the day gets longer over time as the speed of Earth’s rotation slows, timekeepers are tossing in a leap second now and then to keep human time keeping pace with the solar system.

As the Earth accelerates, we are faced with an unprecedented possibility: the addition of a “negative leap second.” In other words, Levine says, if the planet continues to rotate too fast, then by the end of the decade, watchkeepers may need to delete an entire second. For example, they might have the clocks skip from 23:59:58 on December 31, 2029 to 00:00:00 on January 1, 2030.

If you ask me about the negatives [leap second] Five years ago, Levine says, “I would have said, ‘Never.'” But over the past year or two, the Earth has definitely been accelerating. Now, if that acceleration continues — there’s something big. if There – then we may need negative progression in second place in about seven years, maybe eight years.”

This has not been done before. Some scientists wonder if doing so could trigger an annoying hiccup in computer systems. Given the way our world continues to surprise us, Levine is not yet convinced that the time will come.

“You must remember, this requires extrapolation over six years—and we’ve been burned before about extrapolation. So, I wouldn’t be willing to bet the farm.”

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