So what will you do with your extra second tomorrow night?

Rare leap second to be added to atomic clocks on Saturday night

Rob Williams
Friday 29 June 2012 16:41
Comments

It oftens feels like there are not enough hours in the day. But are there enough seconds?

The answer is no - according to the impressively named Earth Rotation and Reference Systems Service (IERS).

The IERS, which is responsible for keeping track of the gap between atomic seconds and planetary time will be adding an extra so-called 'leap second' to their atomic clocks this weekend.

On Saturday night, therefore, atomic clocks will read 23 hours, 59 minutes and 60 seconds, before moving onto Greenwich Mean Time at midnight.

The main reference point for how we set out watches are super-accurate atomic clocks. However, the precision of such clocks - which are much more constant than the shifting movement of the earth - can lead to discrepancies.

Uncorrected the leap second would continue to move further ahead leading to, in many years, the sun setting at midday. A leap second performs a similiar function to an extra day in a leap year, which keeps the calendar in time with the seasons.

In recent years a leap second has been added to the atomic clocks every few years, at a slightly more infrequent rate than in the 1970s.

This is despite the long-term slowing of the rotation of the earth caused by earthquakes, tides and other natural phenomena.

"We want to have both times close together and it's not possible to adjust the earth's rotation," Daniel Gambis, head of the Earth Orientation Centre of the IERS said.

Atomic clocks are used to set Coordinated Universal Time, making the adjustments to them more than just a technical oddity.

Time standards on the internet, satellite navigation systems, air traffic control sytems and banking computers are set using the Coordinated Universal Time system.

But the leap seconds are not uncontroversial, and there have been calls for them to be abandoned.

A meeting of the International Telecommunications Union (ITU), the UN agency responsible, failed to reach a decision in January.

People who oppose the leap second want a simpler system, that avoids - they say - some of the costs and margins for error in making the thousands of corrections.

Britain's Royal Astronomical Society says the leap second should be retained until there is a much broader debate on the change.

"This is something that affects not just the telecom industry," said RAS spokesman Robert Massey. "It would decouple time-keeping from the position of the sun in the sky and so a broad debate is needed."

Time standards are important in professional astronomy for pointing telescopes in the right direction but critical systems in other areas, not least defence, would also be affected by the change.

"To argue that it would be pain free is not quite true," Massey said.

Meanwhile people across the UK are unlikely to notice the occurrence of the shortest long weekend this year.

Register for free to continue reading

Registration is a free and easy way to support our truly independent journalism

By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists

Please enter a valid email
Please enter a valid email
Must be at least 6 characters, include an upper and lower case character and a number
Must be at least 6 characters, include an upper and lower case character and a number
Must be at least 6 characters, include an upper and lower case character and a number
Please enter your first name
Special characters aren’t allowed
Please enter a name between 1 and 40 characters
Please enter your last name
Special characters aren’t allowed
Please enter a name between 1 and 40 characters
You must be over 18 years old to register
You must be over 18 years old to register
Opt-out-policy
You can opt-out at any time by signing in to your account to manage your preferences. Each email has a link to unsubscribe.

Already have an account? sign in

By clicking ‘Register’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Join our new commenting forum

Join thought-provoking conversations, follow other Independent readers and see their replies

Comments

Thank you for registering

Please refresh the page or navigate to another page on the site to be automatically logged in