Planet Earth had, on June 29, the shortest day since scientists started using atomic clocks to measure the speed of rotation.
On Wednesday, June 29, the Earth completed the spin, which was supposed to be 24 hours, with 1.59 milliseconds less.
This is the latest record in a series that Earth’s speed has reached since 2020 — the previous record being -1.47 milliseconds, on July 19.
In July, the planet almost surpassed the record again, on July 26, 2022, when it completed a revolution on its axis with -1.50 milliseconds.
When the length of the day increases, it means that the Earth is rotating more slowly. On the other hand, when it is decreasing and becomes a negative number, the Earth is rotating faster.
The planet makes two movements: rotation and translation.
Rotation is what the Earth does around itself—and what makes the Sun rise and set every day. That moment is completed in 86,400 seconds, or 24 hours.
Translation is a full revolution around the Sun, which characterizes the year (made in 365 days).
Generally speaking, scientists have observed that every century, the Earth takes a few milliseconds or more to complete one rotation (where 1 millisecond is equal to 0.001 second).
However, the speed at which the planet completes the movement varies. From one day to the next, the time it takes the Earth to complete one rotation increases or decreases by a fraction of a millisecond.
Why Earth is “in a hurry”
In recent years, the Earth has accelerated. In 2020, TimeAndDate reported that Earth has reached its shortest 28 days since accurate daily measurements using atomic clocks began in the 1960s.
The Earth continued to spin rapidly in 2021, even though the shortest day in 2021 was slightly longer than in 2020.
Now, in 2022, the rotation has accelerated again. According to Leonid Zotov, and the scholars Christian Bizouard and Nikolay Sidorenkov, the current decrease in day length may have something to do with the “Chandler wobble”.
This means that there is a small irregular movement of the geographic poles of the planet across the surface of the globe.
Scientists are expected to present the hypothesis next week at the annual meeting of the Asia Oceania Geosciences Society.
According to the researchers, the decrease in day length could be related to processes in the Earth’s inner or outer layers, oceans, tides or even weather. But this is still uncertain.
For Zotov, no one knows for sure whether the length of the day will continue to decrease or we have already reached the minimum.
“I think there’s a 70% chance that we’re at the minimum,” he said, “and we won’t need a negative leap second,” he said.
A negative leap second would mean that our clocks would skip a second, which could create problems for IT systems.
Source: CNN Brasil
