A rare phenomenon is set to occur on July 22 when the Earth will spin faster than usual, creating one of the shortest days in history. The planet has been rotating at its fastest since records began in 1973, and this speed increase will be barely noticeable – a difference of just 1.34 milliseconds from the standard 24 hours.
The trend is part of a puzzling acceleration in Earth’s rotational behavior that started in recent years. If it continues, atomic clocks may need to account for a negative leap second by 2029, a concept that has never been implemented before.
Scientists have been studying this phenomenon, with some attributing it to the redistribution of mass due to melting polar ice and rising sea levels. However, others believe that changes in Earth’s liquid core might be responsible, redistributing angular momentum to make the mantle and crust spin faster.
Leading expert Leonid Zotov predicts that Earth’s rotation may soon slow down again if his theory is correct. The sudden speeding-up could be a temporary anomaly in the planet’s long-term trend towards slower rotation and longer days.
The study of Earth’s rotational behavior is complex, with many factors at play. Scientists are still working to understand the cause of this acceleration and how it will affect our understanding of timekeeping.
Source: https://www.space.com/astronomy/earth/earth-will-spin-faster-on-july-22-to-create-2nd-shortest-day-in-history