Leap seconds are present in our clocks even if we are not able to notice them. One would think that time is an exact measurement that marks the cycles necessary for us to function on Earth, not only the circadian cycle, but the accounting of time for technology and its devices that require an exact time to be functional. But time as we know it is a measurement invented by man, and as such, it is imperfect.
Humanity has found two different ways to establish the measurement of time. The first is the best known; it is obtained from calculations of rotational motion, i.e., exactly how long it takes for the Earth to spin around itself. The other way is on a microscopic scale, obtained through the so-called atomic clocks that use the vibrations of cesium atoms to measure time incredibly accurately.
The main problem is that the Earth is capricious and complex, and does not always take the same amount of time to rotate around itself. This is where an offset occurs in the clocks that are incredibly timed because although the variations in the length of the days are of course very small, in the long run, they accumulate to a full second.
To avoid these mismatches, the International Bureau of Weights and Measures (BIPM), responsible for the international standard that sets the world’s clocks, has had to invent leap seconds, which are somewhat like the days we add to leap years, hence their name.
When there is an offset between astronomical time and universal time, which is the time we all use, a leap second is added to the clocks. Up to the year 2022, 27 leap seconds have been added in different years, the last one was in 2016.
There will be no more leap seconds
For humans, leap seconds go virtually unnoticed, as it is such a small period that we are not even able to notice them. The problem comes when it comes to satellite or computing devices that require a perfectly timed time to function. Leap seconds can cause mismatches even in technology associated with space travel.
It is for this reason that the International Bureau of Weights and Measures has decided to eliminate leap seconds forever as of 2035. For now, clocks will continue to be increased by one second as needed, but from 2035 onwards there will be no more adjustments between astronomical and universal time.
The decision was taken after the meeting of the 59 member states during the General Conference on Weights and Measures, held last Friday in Paris. The head of the BIPM department told AFP that the decision will make possible “a continuous flow of seconds without the discontinuities currently caused by irregular leap seconds.”
After the stipulated year, the BIPM will let astronomical and atomic time gradually drift apart. It will not be until the next conference, to be held in 4 years, that physicists will decide on the appropriate adjustments to bring the two clocks back into synchronization.
Story originally published in Spanish in Ecoosfera