sun rays piercing over earth's horizon

Scientists baffled as Earth spins faster than usual – making days shorter

Scientists have discovered the Earth is spinning faster than usual. This is making days shorter; in fact, June 29, 2022, is the shortest day ever recorded, with the Earth’s full rotation taking 24 hours minus 1.59 milliseconds. If this rapid rate continues, scientists warn that we may need to remove a second from our clocks. 

As astrophysicist Graham Jones reported, “If Earth’s fast rotation continues, it could lead to the introduction of the first-ever negative leap second. This would be required to keep civil time — which is based on the super-steady beat of atomic clocks — in step with solar time, which is based on the movement of the sun across the sky. A negative leap second would mean that our clocks skip one second, which could potentially create problems for IT systems.[1]

The Longest Recorded Day

In general, the Earth’s speed fluctuates over long periods of time, taking a couple of milliseconds or so longer or shorter for one rotation. Still, the length of a day is determined by how long it takes for Earth to spin completely on its axis, which takes 86,400 seconds or better known as 24 hours. Until a few years ago, in fact, many believed the Earth was slowing its rotation. The International Earth Rotation and Reference Systems Service (IERS) even started adding sporadic leap seconds to make up for the slowed pace. But the last leap second occurred on December 31, 2016.

While the Earth might be slowing down overall, it has certainly picked up speed over the last few years. In 2020, there were 28 shortest days recorded since the 1960s, when timing using atomics clocks started. The shortest day in 2020 was July 19 with negative 1.47 milliseconds.

In 2021, the Earth still turned quickly but the shortest day of the year was still longer than the ones in 2020. But in 2022, June 29 set the record for the new shortest day at negative 1.59 milliseconds. And that record was almost beaten on July 26, with the length of the day coming to negative 1.50 milliseconds. 

Read: 50 Years Ago NASA Sent a Map Into Space to Help Aliens Find Earth—Now They’ve Got An Awesome Update

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What is making the Earth spin faster? 

Well, scientists do not know, and neither can they make confident predictions on how long days will be next year, but there are some theories. One involves the melting of the glaciers that could be reducing the weight on the north and south poles. Another attributes it to motions in the Earth’s inner molten core. One involves seismic activity, and yet another involves gravity from the moon.

But Leonid Zotov, a professor of mathematics, popularized the theory that the Earth is spinning faster due to the “Chandler wobble.” This wobble was first discovered in the 1880s by astronomer Seth Carlo Chandler, who noticed the poles wobbled over 14 months. This periodic movement slowed down in the 2000s, disappearing between 2017 to 2020. However, Zotov’s theory has yet to be peer-reviewed. [2]

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Why does the Earth’s speed matter?

It’s impossible for people to notice a day is shorter by a millisecond or two without proper equipment. Still, the Earth spinning faster could have real-life consequences. Essentially, atomic clocks, which are used in GPS satellites, don’t change depending on the Earth’s rotation. In short, satellites can become useless. An increase in speed means the Earth is returning to the same position earlier, and half a millisecond can mean a shift of 10 inches or 26 centimeters at the equator. Similarly, smartphones, computers, and communication systems synchronized with Network Time Protocol (NTP) servers can run into similar consequences. [3]

To solve this, timekeepers may need to add a negative leap second, also known as a drop second, to keep up with the revolving planet. Of course, doing so opens its own can of worms, such as reevaluations on how we define time, and if there’s a better method of doing it. However, it’s likely no change will be needed, aside from celebrating June 29, 2022, as the shortest day in history — for now. [4]

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Sources

  1. “Earth Sets New Record for Shortest Day.” Time and Date. Graham Jones and Konstantin Bikos. July 27, 2022
  2. “June 29 was the shortest day in recorded history — a ‘wobble’ in the Earth’s spin shaved off 1.59 milliseconds.Business Insider. Marianne Guenot. August 1, 2022
  3. “Earth Is Suddenly Spinning Faster. Why Our Planet Just Recorded Its Shortest Day Since Records Began.” Forbes. Jamie Carter. July 28, 2022
  4. “Oh my days! Midnight comes a fraction sooner as Earth spins faster.The Guardian. Ian Sample. August 1, 2022
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