Scientists have observed that Earth’s rotation is briefly accelerating this summer, resulting in slightly shorter days. On July 9, July 22, and August 5, the planet is expected to complete its spin about 1.3 to 1.5 milliseconds faster than the usual 24-hour period.
Though a millisecond — one-thousandth of a second — may seem insignificant, experts say such changes are closely monitored using atomic clocks, which track time with astonishing accuracy. These clocks, used in satellite systems, communications, and even military technology, are capable of detecting minute deviations in Earth’s rotational speed.
In recent years, Earth has recorded some of its shortest days since atomic clocks were introduced in the 1950s. The record-holder came on July 5 last year, when a day was shortened by 1.66 milliseconds. Another notably short day was observed in June 2022.
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Researchers believe the moon’s position may be influencing these shorter days. During these dates, the moon is near its farthest point from Earth, known as apogee. While this typically causes Earth’s rotation to slow, scientists note that the moon’s tilted orbit—currently near its steepest angle—might be accelerating the planet’s spin instead.
Earthquakes, shifting mass, and even climate change can affect rotation too, but none of these seem to be the cause this time. NASA-backed studies have shown that melting glaciers and rising sea levels usually slow down Earth’s spin rather than speed it up.
