At midnight on tonight an extra second will be added as recommended by the International Earth rotation and Reference systems Service (IERS). That means for the last minute of 2008 there will 61 seconds.
Leap Seconds have been added nearly every year since the inception of UTC (Coordinated Universal Time) in the 1970’s. The extra second is added to ensure UTC keeps in synch with GMT (Greenwich Meantime or sometimes called UT1). GMT is the traditional 24 hour clock system where a day is defined as the rotation of the Earth which takes 86,400 seconds for a complete revolution.
Unfortunately the Earth can often be a little tardy in its spin and if the extra seconds were no added at the end of the year to compensate eventually the two systems (UTC and GMT) would drift apart. In a millennium the time difference would only be an hour but many argue to a have a time system that does no correspond to the movement of the heavens would be irrational and occupations such as farming and astronomy would be made more difficult.
However, not everybody sees it that way wit some arguing that as te entire world’s computer networks are synchronised to UTC using NTP servers then the fudging of the extra second causes untold amounts of trouble.
Now a group within the International Telecommunications Union, called has recommended abolishing the leap second. Group member Elisa Felicitas Arias, of the International Bureau of Weights and Measures in Paris, France, argues that a timescale that doesn’t need regular tweaking is essential in an increasingly interconnected world. What’s more, she says, ships and aircraft now navigate via GPS rather than the old time system. GPS runs on a version of atomic time.
Next year, member states of the ITU are due to vote on the proposal. If 70 per cent support the idea, an official decision will be made at the World Radio Conference in 2011. According to a report co-authored by Felicitas Arias, most member states support the idea. The UK, however, is against reworking its laws, which include the solar timescale Greenwich Mean Time. Without the UK abolition may be difficult, says Felicitas Arias.
“In theory, adding a second is as easy as flipping a switch; in practice, it rarely works that way,” says Dennis McCarthy of the US Naval Research Laboratory, which provides the time standard used by the US military. Most likely to be affected are IT systems that need precision of less than a second. In 1998 – two leap seconds ago – cellphone communications blacked out over part of the southern US. Different regions of service had slipped into slightly different times, preventing proper relaying of signals.
All quotes attributed to the BBC