Read, Watch or Listen

Earth experienced its shortest day on record on July 9th, 2025, clocking in 1.3 to 1.6 milliseconds shorter than 24 hours. This is attributed to the moon's gravitational pull and its maximum declination. Scientists predict two more shorter-than-usual days this summer. While Earth's rotation generally slows down over centuries due to tidal friction, shorter-term variations in rotational speed occur. The possibility of a "negative leap second" to account for faster rotation is being considered, a first in history, potentially around 2029.

Prepared by Olivia Bennett and reviewed by editorial team.