NPLs atomic clocks adjusted at midnight
Timekeepers at the NPL will today add one extra second to the atomic clocks that determine the precise time in the UK.
The International Bureau of Weights and Measures at the NPL also acts as the official atomic time keeper for the world – comparing astronomers precise rotation timings to UTC – if these measurements differ by more than 0.9 seconds then the clocks are adjusted.
These rare leap-seconds are added or removed from the final minute of the year to take into account the slight variation in speed of the Earth’s spin caused by changes in the Earths atmosphere and core.
London’s Big Ben will also be adjusted and the BBC will add one extra “pip” to their timing system just before midnight.