Saturday Was Bit Long – by a Second, Actually

The transition from June to July will be extended by circumstances beyond everyone's control.  The last minute on June 30,2012 will be 61 seconds long, as time keepers will add a "leap second" as a compensation just before midnight to make up for a gradual slowdown in the Earth's rotation.  That's 8 pm EDT on Saturday. Universal time will be 11:59:59 and then the unusual reading of 11:59:60 before it hits midnight.

In order to manage the wobbly-wobbly movements of our world, the experts at the International Earth Rotation and Reference System Service make the adjustment when the planet's movement falls out of sync with atomic clocks that measure time.

The planet takes just over 86,400 seconds for a 360-degree revolution. But it wobbles on its axis and is affected by the gravitational pull of the Sun and Moon and the ocean tides, all of which stop the rotation by a tiny sliver of a second. Because of this the Earth gets out of step with International Atomic Time (TAI), which uses the pulsation of atoms to measure time to an accuracy of several billionths of a second.

This week's change comes after nearly four years without a leap second the last one was at the end of December 2008, the 25th overall. It would be only 2015 or 2016 that researchers would make another such similar attempt.

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

RAS spokesman Robert Massey said, "This is something that affects not just the telecom industry. It would decouple timekeeping 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, and would also be affected by the change."