The Earth’s rotation is accelerating unexpectedly, causing three remarkably shorter days this summer. Normally, each day on our planet lasts about 86,400 seconds, but from July 9 to Aug. 5, the clock will be shaved off by up to 1.51 milliseconds.
Scientists attribute the shortening of days to the Moon’s position, as it affects the rate of Earth’s rotation. The shortest day since 2020 was recorded on July 5, 2024, when it fell to 1.66 milliseconds shorter than average.
Experts are baffled by the sudden acceleration, with Moscow State University’s Leonic Zotov stating that “Nobody expected this.” While ocean and atmospheric models cannot explain the huge change, most scientists believe it is related to something within the Earth.
As a result, Earth’s timekeepers might need to introduce a “negative leap second” in 2029. According to a study published last year, this drastic measure would ensure that our clocks remain aligned with the planet’s rotation.
Source: https://nypost.com/2025/07/02/science/summer-2025-will-have-three-of-the-shortest-days-on-record-as-earths-rotation-unexpectedly-accelerates