Times are changing. Delegates will gather in Geneva this week to vote on a plan to alter the way we measure the passage of the seconds, minutes and hours that make up the day. If agreed, telling the time will no longer be determined ultimately by the sun's position in the sky. Instead, we will rely on highly accurate atomic clocks as our sole method for determining the length of a day and a year.
The key issue which is to be debated at the International Telecommunication Union conference on January 19 is the proposal - supported by the US and France - to abolish the "leap second". These are added occasionally to the length of the year in order to keep Universal Time in step with the Earth's unpredictable rotation, which is slowing down, - as determined by the position of the sun in the sky -fractionally longer.
It is proposed that at midnight on June 30, the clocks that are used as the basis for Universal Time will display the time 23:59:59 for two seconds rather than one, thus adding a second to 2012.
However, that change could be the last of its kind for the leap second and for our fiddling with time.