Scientists Puzzled by Earth’s Rotation Speed Suddenly Increasing, Leading to Unexpectedly Short Days

“The cause of this acceleration is not explained.”

Spin Cycle

The Earth’s rotation is about to accelerate significantly.

According to scientists, July 9, July 22, and August 5 of this year will be some of the shortest days in recent memory as a result, slicing well over a millisecond off the usual 24 hours, Timeanddate.com reports.

That’s despite the Earth’s full rotation taking almost exactly 86,400 milliseconds, the equivalent of 24 hours.

The short upcoming days buck a decades-long trend. Since 1972, scientists have sliced a “leap second” from the clock a whopping 27 times thanks to a steady deceleration.

Our planet’s sudden — and significant — acceleration caught scientists by surprise.

“Nobody expected this,” Moscow State University astronomer Leonid Zotov told Timeanddate.com. “The cause of this acceleration is not explained.”

“Most scientists believe it is something inside the Earth,” he added. “Ocean and atmospheric models don’t explain this huge acceleration.”

Slicing Seconds

Scientists have long found that numerous factors can influence the speed of the Earth’s rotation, from changing sea levels to the Moon steadily increasing its orbit away from our planet.

Using atomic clocks, we’ve been able to keep extremely close tabs on how these influences are affecting how we measure time on Earth. While its rotation had been steadily declining, the Earth reversed the trend in 2020, beating 60-year-old records for the shortest days 28 times.

One possible explanation is that the Moon could be at its furthest point from the Earth’s equator, as IFLScience explains.

Another culprit could be powerful earthquakes knocking the Earth off its already tilted axis. In 2011, scientists found that a 9.0 earthquake in Japan may have been ferocious enough to shorten days on Earth by offsetting its axis by roughly 6.5 inches.

But whether the Earth will continue its surprising trend of spinning faster and faster remains a subject of debate.

“There is a general consensus the Earth will slow down again (deceleration will win), but there is a risk that acceleration may be effective for a few decades,” Geoscience Australia scientist Oleg Titov told The Guardian.

More on Earth’s rotation: Scientists Build Device to Generate Electricity Using the Earth’s Rotation