Ditching the leap second would mean decoupling clock time from the Earth’s rotation – from day and night itself

Dava Sobel in Aeon:

ScreenHunter_249 Jul. 27 21.58In 2015, leap seconds will come up for international review. Four decades of use have allowed time for certain factions to find fault with the leap second, and to question whether periodically resetting all the clocks in the world is actually worth the bother.

I can certainly sympathise with that sentiment. The semi-annual switch between standard time and summer time all but undoes me. Only one of my clocks picks up the radio signal telling its hands when to ‘spring forward’ or ‘fall behind’, and I resent having to fiddle with all the others. Then, too, I find the single hour’s time difference more disturbing to my equilibrium than a multi-time-zone dose of travel-induced jet lag, probably because the seasonal change is imposed upon me. Nothing would please me more than to see my government abolish daylight-saving time, which is already widely ignored by other countries. It is ignored with impunity even by individual states and counties within the continental United States. Ending it at a stroke would not cause the slightest wrinkle in time.

The leap second, on the other hand, though only one-60th of one-60th of one hour, is not so easily dispatched. Neither the US Congress nor the British Parliament wields the clout to topple it. A leap second doesn’t just reset the clock; it changes the length of a minute. Leap seconds are persistent, too. Eliminating future ones will not expunge the 25 already in existence. Embedded in a wealth of time-stamped data sets, their presence will be felt indefinitely, like 25 peas under the mattress of history.

More here.