On 1st Jan 2009, at 7:59:59 Singapore Standard Time, a leap second is to be added to the Coordinated Universal Time (UTC). The Singapore Standard Time, which is 8 hours ahead of the UTC, will be delayed by one second and the adjustment will be done in two seconds at 8am Singapore Time – ie. 7:59:59, 7:59:60, 8:00:00.
The leap second was first introduced in 1972 and this is the 24th adjustment since then. There are two commonly used time scales in the world, one is the UTC based on the worldwide network of highly precise atomic clocks, and the other is astronomical time which is based on the Earth’s rotation. Since the Earth‘s rotation has been slowing down, it is necessary to insert an extra second to the UTC so that the UTC would agree with astronomical time to within 0.9 second. The decision to make the leap second adjustments in the UTC is the responsibility of the Earth Orientation Centre of the International Earth Rotation and Reference System Service (IERS) based in Paris. Under the international pact, the preference for leap second adjustment is usually made on 30 Jun or 31 Dec.
The National Metrology Centre, as the custodian of Singapore Standard Time, is responsible for precise determination and dissemination of time in Singapore. Our time dissemination system will be adjusted to include the leap second correction on 1st Jan 2009. Precise measurements are necessary for telecommunications and other technologies.
