It seems like we will have to wait an extra second to ring in the new year 2006, and that’s because a “leap second” is being added to the last minute of the last hour of 2005.
Leap seconds are used to synchronize precise atomic clocks with the more variable rotation of the Earth.
Although the Earth’s rotation with respect to the sun has been used since ancient times to know the time of day, it is not like clockwork, and can speed up or slow down by a few thousandths of a second a day. This means that every day is not precisely 24 hours, or 86,400 seconds.
Without leap seconds, Coordinated Universal Time would slowly get out of sync with the time it feels like on Earth.
Leap seconds were first added in 1972, and a body called the International Earth Rotation and Reference Systems Service, in Paris, decides when one is needed.
The last leap second was added in 1998. This will be the 23rd one.
[Source: The Globe and Mail]