Named the shortest day of the year

Earth accelerates rotation: on July 10, 2025, the day shortened by 1.36 milliseconds. This is reported by the authoritative scientific publication Space.com, citing data from international monitoring services that use ultra-precise atomic clocks to track the rotation speed of our planet.

The standard duration of a day is exactly 86,400 seconds, but in recent years, the scientific community has increasingly registered microscopic deviations from this norm. According to expert calculations, on July 5, 2025, our planet also demonstrated accelerated rotation — a complete revolution around its axis was completed 1.25 milliseconds earlier than the scheduled time. It is expected that on July 22, a similar anomaly will occur: the duration of the day may decrease by 1.34 milliseconds.

The most significant reduction was recorded on July 5, 2024, when Earth completed a full rotation a whole 1.66 milliseconds faster than standard time. Such high-precision measurements became available since 1973, when atomic clocks capable of registering the smallest changes in the rotation speed of our planet were introduced.

Despite the fact that the reduction of the day by thousandths of a second is imperceptible in everyday life, scientists are closely observing this phenomenon. According to specialists, the acceleration of Earth's rotation may indicate complex processes occurring in the depths of the planet.

"The reason for this acceleration is not revealed," commented Leonid Zotov, a leading specialist in Earth rotation.

He indicated that a possible explanation could be the redistribution of masses inside the planet, tectonic processes, or changes in the core. Zotov also emphasized that in the future, Earth may begin to slow down again, as its rotation speed is unstable and depends on a whole complex of internal and external factors.

To date, the decrease in the duration of the day does not affect everyday life, however, in the future, it may be necessary to adjust Coordinated Universal Time (UTC), which is currently maintained by adding or excluding so-called "leap seconds".