For precise timing every ‘leap’ second matters

There is unlikely to have been anyone who wondered why the evening of June 30 was longer than usual when a ‘leap second’ was added to the clock. These are the ever so tiny adjustments that are made to the atomic clocks to keep them in sync with the Earth’s rotation. The correction would not have been necessary if the period that the Earth takes to revolve round its axis did not vary because of the effects of tides and earthquakes. Since it does, resulting in a slowing down of the rotation, the super-accurate clocks have to be tweaked to ensure that they do not fall of step with the turning of the Earth. If such fine-tuning was not done, then over thousands of years, the rising of the Sun would shift from dawn to noon to night.

The slowing of the rotation has another consequence far more fearful than the time of the sunrise. It is the Earth’s slow descent into the Sun. Since that will take billions of years, only science fiction writers need to take cognisance of it for the sake of their story lines. For the rest, it is the correctness of the time through the addition of ‘leap’ seconds, and of the seasons with the addition of the ‘leap’ years, which are of consequence.

The importance of these alterations lies in making the general public aware not only of the awesome nature of the astronomical phenomenon, but also of the magnificence of the scientific achievement that monitors these changes and ensures that the clocks and calendars remain in sync with the Earth’s rotation round its axis and journey round the Sun.

The International Earth Rotation and Reference Systems Service, established in 1987 and located in Paris, France is responsible for keeping track of the gap between atomic and planetary time and issuing directives on the addition of leap seconds.