World timekeepers wrangle over scrapping leap second

September 20, 2013 by Jonathan Fowler
An old clock is pictured on March 22, 2013, in Angers, western France.

Timekeeping experts failed Friday to reach a decision on scrapping the four-decade-old practice of adding extra seconds to clocks, a system opponents say causes headaches in a hi-tech, interconnected world.

After deferring a decision almost two years ago, members of the 193-nation International Telecommunication Union aim to settle the issue by 2015, but divisions persisted as a week of talks among technical experts wrapped up in Geneva.

The issue of scrapping the "" has been on the table for a decade.

Like a February 29 added to calendars in quadrennial leap years, leap seconds are used to keep in sync with the earth's rotation, which is slowed by the of the Sun and the Moon.

Every time a second is added, the world's computers need to be manually adjusted, a costly practice that boosts the risk of error and raises the spectre of havoc when differently-timed systems communicate.

But without leap seconds, ultra-accurate hi-tech clocks would race ahead of skewed , amounting to a discrepancy of about 15 seconds every 100 years, experts believe.

Leap seconds were created in 1971 in an effort to simplify adjustments to Coordinated Universal Time (UTC), which had been defined by ITU members in 1963 as a successor to Greenwich Mean Time.

They have been added on 24 occasions since then, and are always introduced at midnight on June 30 or December 31.

Breakneck technological change has increase calls for a move to a continuous, global time-scale, given that global navigation or require a continuous, uninterrupted time reference, and Internet communication straddles borders.

"A second today is much larger than it was back in 1971," said Ron Beard, head of the ITU's time signals arm.

"With the Internet and telecommunication systems that we have now, there are hundreds of thousands of interactions and transactions through that network every second. And if that network is one second out, how many transactions can you affect?"

The leap second battle lines do not reflect the traditional international diplomat divisions, with countries including the United States, France and Japan in favour of ditching them, and Britain, China and Canada among those wary of the idea.

"A variety of systems using UTC have been developed over the past 40 years since the introduction of the leap second and proponents argue that UTC should be maintained," said Francois Rancy, head of the ITU's radiocommunication bureau.

"Strong arguments are also made to abolish the leap second in favour of a continuous reference time scale as a measure to increase the reliability of systems that depend on time to reduce costs and avoid unnecessary disruptions," he added.

Explore further: World timekeepers split on scrapping leap second

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5 / 5 (4) Sep 20, 2013
Dear Time Lords,
While you're fixing the leap-second issue, also stop the pointless temporal gymnastics of "daylight-saving time".

Thank you,
1 / 5 (1) Sep 21, 2013
So, we are ready to ditch a very successful system because computer programmers are not clever enough to represent the real world as it exists?...give me a break!
5 / 5 (2) Sep 21, 2013
While you're fixing the leap-second issue, also stop the pointless temporal gymnastics of "daylight-saving time".

Every now and then I use daylight-saving time to test the acumen of people by telling them that extra hour of daylight is, without a doubt, the primarily cause of global warming. An impressive (or should I say depressing) number of people consider that for only a few seconds before agreeing.

By the way here's a suggestion. During those "spring-forward/fall-back" weekends, I lessen the impact on my circadian rhythms by adjusting my clocks by only 5 minutes every few hours. By spreading that hour out over two days you don't notice it as much.
not rated yet Sep 23, 2013
So, we are ready to ditch a very successful system

Successful at ...what exactly?

There's a lot of legacy systems out there where the leap second wasn't considered (programmed in languages that almost no one knows anymore - and certainly not in a state that anyone could review/verify the changes according to the required processes if they were made)

Now such a change in software might not seem like much. But it does introduce a discontinuity in handling states for that one second.
And if we have learned anything in the past it is that hackers are exceedingly clever at using discontinuities to their advantage. (E.g. with the rate of data transfer and computation speeds available today - if you could have full control of stock exchanges for a second then you could crash the global economy, easily)

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