20 Jan 2012

Decision on abolishing leap second deferred

2:33 pm on 20 January 2012

Experts meeting in Switzerland have deferred a decision on whether to abolish the leap second.

Leap seconds are occasional one-second adjustments to the world's time that keep very accurate modern clocks in synch with the rotation of the Earth.

The proposal to eliminate them was being discussed at the International Telecommunication Union (ITU) in Geneva.

The experts were unable to reach a consensus, so moved the matter to a meeting in 2015, the BBC reports.

Some countries such as the United States want to abolish the adjustments, saying they create problems for services that require a continuous time scale, such as the internet, the BBC reports.

But Britain and others warn such a change would see the time recorded on the Earth's clocks and that based on the Earth's rotation drift increasingly far apart.

An ITU spokesman said that Canada, Japan, Italy, Mexico and France all supported the United States' stance on losing the leap second, while Germany, like the UK, wanted the extra second to stay.

The Earth speeds up and slows down as it spins, which means that while one rotation is one day, some days end up being a few milliseconds longer or shorter than others, the BBC reports.

As a result, leap seconds were established in 1972 to keep the time told by atomic clocks and the Earth's time in phase.

They are added once the International Earth Rotation Service, which monitors the Earth's activity, has found that the two have drifted out of time by 0.9 seconds.

Six month's notice is given for these incremental additions.

Those who want to abolish the leap second say these one-second jumps are becoming increasingly problematic for navigation and telecommunication systems that require a continuous time reference.

These include satellite navigation, financial services, the internet, flight control and power systems.