The International Earth Rotation and Reference Systems Service (IERS) is constantly measuring the length of our days to a high level of accuracy.
Scientists use atomic clocks to monitor Earth’s rotation with millisecond precision, and have been keeping records since 1972.
Since 2020, Earth has repeatedly broken its own speed records.
The shortest day ever measured occurred on 5 July 2024, when Earth’s rotation was completed 1.66 milliseconds faster than usual.
According to the IERS, earlier this month, 9 July, was the shortest day recorded this year, clocking in at 1.36 milliseconds less than 24 hours.
Whilst, today – 22 July – Earth is expected to complete its spin 1.34 milliseconds early, making it a close runner-up.
