Today’s rotation is inexplicably accelerating, making it one of the shortest days of the year.
While summer days are certainly longer, July 9th, 2025, will be 1.3 ms shorter than the average.
This speed fluctuates slightly, but it generally takes 24 hours, or 86,400 seconds, for one complete rotation around the axis. To monitor these variations, International Earth Rotation and Reference System Services (IER) continuously tracks the length of the day with remarkable precision.
In 2020, the IER noted that our planet has been spinning faster and has continued this trend since then.
Their data suggests that the shortest days of the year will occur on July 9th, July 22nd, and August 5th, when the moon is at its farthest from the equator.
The moon subtly influences Earth’s rotation through tidal braking, where its gravitational pull slightly distorts our planet.
This phenomenon not only creates tides but also gradually siphons off angular momentum from Earth’s rotation, slowing it down by about 2 ms each century.
This means that during the Triassic period, around 200 million years ago, a day was just under 23 hours long. After another 200 million years, we can expect days to extend to 25 hours.
IERS may implement a second leap second to ensure that high-precision clocks remain accurate. The most recent leap second was added on December 31, 2016.
During times when the moon is far from the equator, the impact on Earth’s rotation is less pronounced, causing these days to be slightly longer. However, the duration seen in recent years is about half of what it was before 2020.
Several events can alter Earth’s rotation, such as the 2011 9.0 magnitude Japan earthquake, which shortened the day by 1.8 microseconds, but the cause of the current accelerating trend remains unknown.
A gradual slowdown is unlikely to have any catastrophic consequences for our planet. The time difference is too minimal for most to notice—you may need to consider skipping a leap second in 2025, with one potentially added again in 2029.
Regardless of the cause, this phenomenon is unlikely to be permanent, and our planet will eventually revert to its long-term rotation pattern.
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Source: www.sciencefocus.com
