www.timeanddate.com By Graham Jones and Konstantin Bikos
Many of us wish we could get through this difficult year as quickly as possible. Seems the Earth feels the same way—it has been spinning unusually fast lately. 2020 included the 28 shortest days since 1960.
Earth set a new record for the shortest day of the atomic-clock era on June 29, 2022. Read our latest story.
Atomic Clocks Expose Earth’s Irregular Speed
The Earth is an excellent timekeeper: on average, with respect to the Sun, it rotates once every 86,400 seconds, which equals 24 hours, or one mean solar day.
But it is not perfect. When highly accurate atomic clocks were developed in the 1960s, they showed that the length of a mean solar day can vary by milliseconds (1 millisecond equals 0.001 seconds). These differences are obtained by measuring the Earth’s rotation with respect to distant astronomical objects, and using a mathematical formula to calculate the mean solar day…
