Earth’s fastest spin: July 9 2025 to be shortest day ever recorded, scientists eye rare negative leap second

Earth is spinning faster, making July 9, 2025, the shortest day since 1960 by 1.3 to 1.6 milliseconds, primarily due to the Moon’s alignment. While imperceptible in daily life, this speedup may necessitate a negative leap second in 2029 if the trend continues. Scientists are closely monitoring these changes to refine climate models and satellite navigation.