our home The planet is in a hurry. On June 29, 2022, Earth completed the shortest day since scientists began keeping records in the 1960s, pulling off a full rotation 1.59 milliseconds faster than normal.
Terrestrial haste is a trend. In 2020, the planet recorded 28 shortest days on record, and it continued to spin faster in 2021 and 2022. Before scientists could verify the timing of that record-setting day of June 29, our world nearly outgrew itself: it had been shining since July 26, 2022, 1.50 milliseconds ahead of schedule.
We’ll likely see more record-short days as Earth continues to accelerate, says Juda Levin, a professor at the University of Colorado-Boulder and a longtime expert at the National Institute of Standards and Technology (NIST). He says that as Earth’s days are getting shorter, this is no cause for alarm, as the actual time difference is equal to fractions of a second over the course of a year. But the strange thing is that, while scientists know that changes in Earth’s inner and outer layers, oceans, tides and climate can affect how fast it spins, they don’t know what the current haste is.
Nobody is perfect – Not even our planet. The Earth rotates on its axis on an average every 24 hours or every 86,400 seconds. But for a variety of reasons, from the planet’s imperfect shape to its complex interior, every day isn’t exactly the same as the day before.
What’s more, a day lasting exactly 24 hours is just the standard we’ve come to expect. immediately, The Earth’s rotation has long been slowing down because of the Moon’s pull on our world. A few hundred million years ago, for example, an Earth day was only 22 hours long. In the coming millennia, Earth Day will last longer.
So what gives with the short days of the late, short the longer term trend? One hypothesis that has been floated so far is related to the “Chandler Wobble”. Discovered in the 1800s, this phenomenon explains how a not perfectly round Earth ever wobbles so little, like a spinning top slows down. Leonid Zotov told timeanddate.com that the wobble mysteriously disappeared between 2017 and 2020, which may have helped Earth speed up the day a bit.
Another idea is that climate change may be affecting the planet’s rotation speed. When glaciers melt in the ocean, the Earth’s shape changes slightly, flattens at the poles and emerges at the equator. But Levine says this effect can’t explain why the planet would suddenly spin faster because melting glaciers should have the opposite effect: The planet’s moment of inertia would increase, which would slow us down.
For Levine, the likely culprit is more mundane.
“One of the possibilities is an exchange of motion between Earth and the atmosphere,” he says. “The sum of those two is constant, meaning, for example, if the atmosphere slows down, the Earth accelerates. Or conversely, if the atmosphere accelerates, the Earth slows down “
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The same thing could happen inside our world: it’s possible for the deep core and mantle – the large layer that exists between the core and the surface – to move at slightly different speeds. They speculate that there may be an exchange of angular momentum between Earth’s deep core and mantle.
“Both of those effects … can either pump momentum into the Earth’s surface, or take momentum from the Earth’s surface,” Levine says. But the dynamics of the atmosphere and Earth’s interior are so complex that, at least for now, it is impossible to pinpoint any one of these factors as a definitive cause of the planet’s rapid motion.
nature doesn’t always obey To the rigors of a clock or a calendar, and planetary timekeepers are accustomed to making some changes. For example, a leap year exists because we need an extra day every four years to keep the 365-day calendar in sync with Earth’s revolution around the Sun. Because the days are getting longer over time as the Earth’s rotation speed slows, a leap is made from time to time to keep humans in step with the solar system.
With the Earth accelerating, we are facing an unprecedented possibility: adding a “negative leap second”. In other words, Levine says, if the planet continues to spin too fast, the clock owner may have to remove a full second by the end of the decade. For example, they might have clocks from 23:59:58 on December 31, 2029 to 00:00:00 on January 1, 2030.
“If you had asked me about the negative [leap second] Five years ago,” Levine says, “I would have said, ‘Never.’ But over the past year or two, the Earth is definitely getting faster. And now, if that speed-up were to continue—and a big If There — then we may need a second negative lead in about seven years, maybe eight. ,
This has never been done before. Some scientists wonder whether doing so could cause annoying hiccups in computer systems. The way our world surprises us, however, Levine isn’t yet convinced that time will pass.
“You must remember, this requires an extrapolation every six years – and we’re already burned out about extrapolation. So, I wouldn’t be willing to bet on the farm.”
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