The world's timekeeping system is changing: "leap second" to be abolished

Representatives of 69 countries around the world have voted to abandon the leap second used in timekeeping and introduce a new system instead. The changes are scheduled to take effect in 2027. This was reported by The Guardian.

The decision was made on October 15 at a conference organized by the International Bureau of Weights and Measures in Versailles, France. According to the new system, the difference between Coordinated Universal Time (UTC) and astronomical time based on the Earth's rotation will be allowed to reach up to one hour. However, the need to correct such a difference may not arise for thousands of years.

In the current time system, a second is added to UTC when necessary to account for changes in the Earth's rotation. This is called a "leap second." But such minor changes can cause malfunctions in computer systems, communication networks, satellites, and power grids.

For example, after a leap second was added in 2012, problems arose in some computer systems. Outages were observed on Reddit and LinkedIn, and delays occurred in Qantas flights.

Scientists explain that the Earth's rotation speed is not constant. It changes under the influence of natural factors such as the planet's internal structure, and processes in the oceans and atmosphere. In the long term, the Earth's rotation slows down, but in recent years periods of acceleration have also been observed.

Therefore, experts have expressed concern that in the future there might be a need not to add, but to remove a second to adjust the time. This is called a "negative leap second" and has not yet been applied in practice. Scientists estimate the probability of such a need arising in the coming decade at approximately 30 percent.

The main goal of the new system is to eliminate frequent minor adjustments in timekeeping and reduce the risk of failures in digital infrastructure. This allows the gap between astronomical time and official time to grow larger, with necessary corrections made only when the one-hour limit is reached.

For reference, in 1967 the definition of a second was established based on the oscillations of a cesium-133 atom. Since 1972, a total of 27 leap seconds have been added to UTC to maintain synchronization with the Earth's rotation. The last such change was made on December 31, 2016.