Earth unexpectedly spins faster, many days are record short in summer 2025

Scientists have just recorded the phenomenon of Earth's rotation accelerating abnormally, making some days in 2025 the shortest since 2020. This development has raised debate about whether the "era of deceleration" governed by lunar tides for millions of years is coming to an end.

Photo Earth unexpectedly spins faster, many days are record short in summer 2025

Record short days since 2020

According to atomic clock data, since 2020, the Earth's rotation speed has tended to increase instead of decreasing as has long been the rule. The most recent record was set on July 5, 2024, 1.66 milliseconds shorter than the standard.

It is forecasted that this year, the three days of July 9, July 22 and August 5 will be shortened by about 1.25–1.51 milliseconds, becoming the shortest days since this phenomenon began.

Unexplained Cause

Researchers have yet to find the exact cause. Some hypotheses have been proposed, including:

Changes in the velocity of the Earth's core,

Seasonal effects of the atmosphere and oceans,

The relative position of the Moon and the equator.

However, none of these hypotheses can fully explain this acceleration trend.

Challenges to the timing system

Each millisecond difference, although too small for humans to perceive, has a major impact on systems that require absolute precision, such as GPS, telecommunications, and data servers. If the trend continues, the world may have to consider negative leap seconds for the first time to synchronize time.

Long-term trend is still slowing

Although the rotation speed is increasing, experts emphasize that in the long term, the lunar tides will still cause the Earth to rotate more slowly, lengthening the day by about 1.8 milliseconds per century. The current acceleration is considered a notable exception to the planet’s natural oscillation cycle.

Sources: GenK, Popular Mechanics, An Giang Online Newspaper, The Sun, Space.