The world may abandon the "leap second"

The world may abandon the "leap second"

For centuries, people have determined the length of a day based on the Earth's rotation.

Previously, one second was considered to be 1/86,400 of a solar day.

However, with the advent of highly precise atomic clocks in the 1960s, the method of measuring time changed. In such clocks, time is determined through the vibrations of cesium atoms.

According to the current definition, one second is the time equal to 9,192,631,770 periods of vibration associated with the cesium-133 atom. Time measured on this basis is called atomic time.

Since 1972, UTC — Coordinated Universal Time — has been used worldwide. It is based on atomic clocks, but in practice, it is periodically adjusted so as not to drift too far from astronomical time, which depends on the Earth's rotation.

The problem is that the Earth does not rotate at an absolutely constant speed. Its rotation rate can slightly speed up or slow up during different periods.

For this reason, a discrepancy arises between atomic time and the time based on the Earth's actual rotation.

To eliminate this discrepancy, a leap second — an extra second — has been introduced into UTC.

Since 1972, such an extra second has been added 27 times.

In recent years, the situation has changed. During certain periods, the Earth has begun to rotate faster than before.

As a result, to correct the problem, the need may arise not to add an extra second, but on the contrary, to subtract one second, that is, to introduce a "negative leap second."

Such a situation has never been observed in history.

Therefore, the concern of experts is mainly related not to time itself, but to modern technologies.

One second is almost imperceptible to a human. However, in fields such as computer networks, telecommunications, databases, financial systems, and satellite navigation, synchronizing time with very high precision is of vital importance.