Earth is set to complete its rotation in a notably shorter time on July 22, 2025, marking it as one of the shortest days ever recorded. The planet will finish a full spin approximately 1.34 milliseconds quicker than the standard 24 hours, a change that, while imperceptible to most, forms part of an intriguing trend in Earth’s rotational behavior observed over recent years.
This acceleration in Earth’s rotation is not a new phenomenon. Historically, a day once lasted around 19 hours during a significant portion of the planet’s early history. According to a study published in 2023, this was largely due to the interplay between solar atmospheric tides and lunar ocean tides. Over eons, however, tidal friction caused by the moon has gradually slowed Earth’s rotation, leading to longer days as the moon moves further away from the planet.
Understanding the Recent Acceleration
From the inception of atomic clock measurements in 1973 until 2020, the shortest day recorded was 1.05 milliseconds less than the standard 24-hour cycle, according to data from Timeanddate.com. Since then, the Earth has consistently set new records for shorter days. The fastest rotation ever measured occurred on July 5, 2024, when the Earth completed its spin 1.66 milliseconds faster than usual.
Looking ahead, scientists anticipate that other dates in 2025, specifically July 9, July 22, and August 5, may also yield notably short days. Recent data indicates that July 10 has emerged as the shortest day thus far in 2025, clocking in at 1.36 milliseconds less than 24 hours. On July 22, Earth is expected to finish its rotation 1.34 milliseconds ahead of schedule, making it the second-shortest day of the year.
Exploring Possible Causes
Despite the intriguing acceleration in rotation, the reasons behind this phenomenon remain unclear. While a study in 2024 proposed that melting polar ice and rising sea levels might influence Earth’s spin, it suggested this redistribution of mass could be moderating the acceleration rather than driving it. A more likely explanation involves the dynamics of Earth’s liquid core, which may be altering angular momentum and influencing the speed of the mantle and crust.
Leading expert on Earth rotation, Leonid Zotov from Moscow State University, commented on the situation, stating, “The cause of this acceleration is not explained. Most scientists believe it is something inside the Earth. Ocean and atmospheric models don’t explain this huge acceleration.” Zotov also speculated that Earth’s rotation may soon decelerate once again. If this prediction holds true, the current speeding up of Earth’s rotation could be a temporary anomaly in the long-term trend of increasingly longer days.
As Earth prepares for another of its shortest days, scientists continue to monitor these changes, seeking to unravel the complexities behind our planet’s shifting rotation.
