Earth’s Rotation Unexpectedly Speeds Up — Three Days This Summer Will Be Over One Millisecond Shorter | WPN World People News

Scientists have observed a rare acceleration in Earth’s rotation during the summer of 2025. On three specific dates—July 9, July 22, and August 5—the length of each day is expected to be slightly shorter than the standard 24 hours, with a reduction ranging from 1.3 to 1.51 milliseconds. Experts note that while this change has little impact on daily life, it may have potential effects on precision technologies such as satellite navigation and international communications.

According to data from astronomical observatories and timekeeping institutions, Earth’s rotational speed has shown signs of increasing since 2020. On July 5, 2024, the Earth recorded its shortest day in history, ending 1.66 milliseconds earlier than usual. The three dates in 2025 may surpass this record.

The exact causes of this phenomenon remain unclear. Some researchers speculate that potential factors include the redistribution of Earth’s mass due to melting ice sheets, atmospheric dynamics, changes in the geomagnetic field, and inner core activity. Meanwhile, the Moon’s tidal forces continue to exert a long-term slowing effect on Earth’s rotation, creating a complex and variable balance.

As technology increasingly relies on precise timing, atomic clocks and international timekeeping standards have been tracking these tiny variations. If Earth’s rotation continues to accelerate, timekeeping authorities may, for the first time, consider implementing a “negative leap second”—subtracting one second from Coordinated Universal Time (UTC) to stay aligned with Earth’s rotation. This would be an unprecedented adjustment.

Although each day is currently only shortened by a fraction of a millisecond, experts emphasize that this provides valuable insight into Earth’s internal dynamics and climatic influences, demonstrating that our planet is still undergoing changes. Scientists will continue monitoring these developments to gain a deeper understanding of Earth’s geodynamics.