Is humankind ready for a giant, second leap?

A top scientist has proposed a new way to reconcile the two different ways that our clocks keep time. Meet - wait for it the leap minute

- MATT RICHTEL

DELEGATIONS FROM D AROUND the world will head to the World Radio Conference on November 20 in Dubai to discuss international treaties involving radio frequencies, satellite coordination and other tricky technical issues. These include the nagging problem of the clocks. For 50 years, the international community has carefully and precariously balanced two different ways of keeping time. One method, based on Earth's rotation, is as old as human timekeeping itself, an ancient and common-sense reliance on the position of the sun and stars. The other, more precise method coaxes a steady, reliable frequency from the changing state of cesium atoms and provides essential regularity for the digital devices that dominate our lives.

The trouble is that the times on these clocks diverge. The astronomical time, called Universal Time, or UT1, has tended to fall a few clicks behind the atomic one, called International Atomic Time, or TAI. So every few years since 1972, the two times have been synced by the insertion of leap seconds pausing the atomic clocks briefly to let the astronomic one catch up.This creates UTC, Coordinated Universal Time. But it's hard to forecast precisely when the leap second will be required, and this has created an intensifying headache for technology the world's timekeepers.