As we all know, our days last 24 hours because it is how long it takes for the Earth to turn around itself , and our measure of time was established with respect to these movements. Until 1972, in fact, we used the GMT time standard (Greenwich Mean Time), which was governed by the mean solar time measured at the Royal Observatory in Greenwich (UK).
However, the appearance of atomic clocks , much more precise, led to the definition of a new standard, Coordinated Universal Time (UTC) , which calculates time based on a weighted average of the signals from these clocks, located at about 70 laboratories around the world.
The problem is that, while the atomic seconds are extremely precise, the rotational and translational movements of our planet undergo slight variations over the years, due, among other things, to the gravitational attraction of the Moon and the Sun. , there is a phase shift between UTC and the Earth’s rotation . To avoid this, the so-called ‘ leap seconds ‘ have been created, which are preferably added in June or December (until now they have always been added, never subtracted, although it is also contemplated to do so if necessary).
“This extra second makes it possible to align astronomical time , which is irregular and determined by the Earth’s rotation, with Coordinated Universal Time , which is extremely stable,” reports the Paris Observatory in a statement. This observatory houses the International Service for Earth Rotation and Reference Systems , responsible for time synchronization. In Spain, the Time Section of the Royal Institute and Observatory of the Navy in San Fernando is responsible, among other things, for the insertion of these leap seconds.
Since 1972, 26 leap seconds have already been used, and the last one was added in June 2015. The next one will be incorporated on December 31 at 23 hours 59 minutes and 59 seconds Coordinated Universal Time . This means that in the regions that are in that time zone, such as the United Kingdom and Ireland, the last minute of the year will have an extra second, while for the rest, the moment will be determined by the time zone in which they live with relative to UTC.
In our country, people who receive the new year in the Canary Islands will also have that second addition to eat the grapes, while in the peninsula, in reality, 2016 will not be the year that has an extra second, since we have a lag of one hour with respect to UTC and, for practical purposes, the increase will occur in 2017.
