Earth’s Accelerating Spin: What Does It Mean for Us?
If you feel that days fly by, it is not just a perception. Our planet is turning faster than ever. On July 22, 2023, Earth is expected to complete its rotation 1.34 milliseconds before the typical 24 hours, marking it as the second shortest day of the year and one of the shortest recorded in history.
Earth Accelerates. Up until 2020, the shortest day on record lasted 24 hours minus 1.05 milliseconds. Since then, each year’s shortest day has exceeded that threshold. In 2020 and 2021, the highest deviation recorded was -1.47 milliseconds; in 2022 it reached -1.59 milliseconds, and in 2023, it rose to -1.31 milliseconds. The shortest day ever documented was on July 5, 2022, only 1.66 milliseconds short of an entire 24-hour period.
2025 Silver Medal. Predictions for the summer of 2025 indicated three key dates when Earth’s rotation might break speed records: July 9, July 22, and August 5. Ultimately, the shortest day of 2025 was on July 10, with a deviation of -1.36 milliseconds. Observations indicate that July 22 will be the second shortest day that year, clocking in at 24 hours minus 1.34 milliseconds. August 5 is projected to be the third shortest, with a deviation of -1.25 milliseconds.
The World Upside Down. The fascinating aspect of this phenomenon is that it contradicts our understanding of Earth’s rotation. For billions of years, the land has been slowing down due to the friction of tides created by the Moon. This satellite siphons rotational energy , causing days to become longer. In fact, during much of Earth’s history, days were approximately 19 hours long.
Why Is This Happening? The reasons for this acceleration remain unclear. Some researchers attribute it to the thawing of polar caps, but the resultant water redistribution near the equator might actually be modulating the acceleration rather than contributing to it.
This strange acceleration of Earth is absent in existing oceanic and atmospheric models, leading the scientific community to search for answers in the depths of our planet. One theory suggests that as the liquid core of Earth slows its movement, angular momentum may be compensated by a slight acceleration of the mantle and crust — the layers we experience on the surface.
The Second Intercalary… Negative. The acceleration of Earth has significant implications for time measurement. Since 1973, atomic clocks have maintained what is known as Coordinated Universal Time (UTC) . Occasionally, an extra “intercalary second” has been added to keep our timepieces aligned with Earth’s rotations, which historically have slowed.
What we face now is a novel scenario: the potential need for a negative intercalary second . If the current trend continues, we might have to subtract a second from atomic time around 2029. This would mark the first time in history this type of correction is made.
Image | NASA
In Xataka | We have known since time immemorial that days last 24 hours. Except when the wind blows.
In summary, the acceleration of Earth’s rotation raises questions that may redefine our understanding of time. Scientists are still piecing together the puzzle, but one fact remains clear: our perception of time might be on the verge of significant change. The implications extend beyond the mere measurement of time, hinting at deeper shifts in our planet’s dynamics that could ripple into various aspects of modern life. As we stand at this unique juncture, it is essential to stay informed and aware of how these changes could affect our daily routines and long-term future on this spinning globe we call home.