The Earth has been spinning faster than ever in recent years, and scientists still aren’t sure why.
While you might have assumed that the planet we reside on has always taken 24 hours to complete a rotation, the length of day actually fluctuates.
While these changes are minimal, more than a billion years ago the Earth was closer to the moon, causing it to rotate a lot faster than it does now – as such, there were only 19 hours in a day.
As the planet’s position in the solar system has continued to shift, so too has its rotation speed, and today a full spin on its axis takes approximately 24 hours.
We know more about the cycles thanks to atomic clocks, which scientists started to use in the 1960s to take accurate daily measurements of the Earth’s rotation.
Sounding like something straight out of a sci-fi movie, these instruments work by using resonance frequencies of atoms to monitor time with extreme precision.
In recent years, researchers have discovered an unusual trend – Earth has been speeding up, with 2020 seeing 28 of the shortest days since they implemented these clocks.
The shortest day that year was on 19 July, when the Earth span 1.47 milliseconds less than 24 hours.
And on June 29, 2022, a new record was set at 1.59 milliseconds less, demonstrating that our planet very rarely hits the 86,400 seconds it’s said to take for a full spin.
But despite these rising speeds, the overall trajectory demonstrates that, on the whole, the days are getting longer – need I remind you of the 19-hour day?
As outlined by Time and Date, every century Earth takes a couple of milliseconds or so longer to complete one rotation.
So what exactly is causing these fluctuations? Scientist Leonid Zotov thinks the recent downward trend of the length of day could be related to the ‘Chandler wobble’.
The term refers to a small and irregular movement of the geographical poles across the surface of the globe.
“The normal amplitude of the Chandler wobble is about three to four metres at Earth’s surface, but from 2017 to 2020 it disappeared,” Zotov told the outlet.
If the Earth’s rotation continues to speed up in the short-term, it could lead to a negative leap second – a second that is suppressed from our clocks to keep them in sync.
Concerns have been expressed that this change could cause glitches in IT systems, although Zotov reassured: “I think there’s a 70 percent chance we’re at the minimum and we won’t need a negative leap second.”
Other theories put forward suggest the planet’s inner or outer layers, oceans, tides or even climate may have an impact on the Earth’s speed.
But as it stands, there is no definitive answer – as for whether or not the days will continue to change on a larger scale, nobody really knows.