The Earth has set itself a new benchmark in timekeeping by recording the shortest day ever since the passage of seconds, minutes, and hours started to be monitored by highly accurate atomic clocks in the 1960's. 

Whereas many scientists believe that the Earth's rotation is slowing down, (chiefly thanks to the Moon whose orbit creates tidal friction that is gradually slowing both the Earth and the Moon down), the so-called 'Chandler Wobble' may well be behind Earth's recent acceleration of rotation.

The 'Chandler Wobble' is the shifting of the exact positions of Earth's north and south poles and on Wednesday June 29 the Earth managed to complete a 'spin' in under 24 hours, 1.59 milliseconds under, to be precise. This was followed by another fast spin on Tuesday July 26, 1.50 milliseconds under 24 hours, breaking the record for the second-fastest day recorded on Sunday July 19, 2020 at 1.47 milliseconds under 24 hours.

Strangely, 2021 showed no spin anomalies but in 2020 scientists recorded the 28 shortest days since 1960. Situations where milliseconds are lost could require if repeated, the instigation of the first ever "drop second", with the official removal of a second from global time.

Whilst there remains an acceptance that the Earth's spin is slowing, hence the introduction a leap second to our calendars, the last of which was added on December 31, 2016, should the acceleration continue, then it could lead to the first ever negative leap-second.