The world time system decided to change due to the rotation of the Earth
The new rules will take effect in 2027, but the first adjustment at once by an hour may not be necessary for thousands of years. Reform to protect computer systems from failure
Representatives of 69 countries at the conference of the International Bureau of Weights and Measures in France voted to replace the leap second with a leap hour when adjusting world time. This is reported by The Guardian.
The decision was made on October 15 at a conference in Versailles. The new system is due to start operating in 2027. It will allow UTC to diverge from astronomical time by up to one hour. At the same time, the first adjustment for an hour, according to experts, may be necessary only after thousands of years.
The reform is designed to reduce the risk of failures in computer systems, telecommunications, power grids and satellite navigation. These systems depend on the exact time, and adding or deleting one second can disrupt their performance. “After 30 years of discussion, the leap second is giving way to the leap hour,” said Setnam Shemar, lead researcher at the UK’s National Physical Laboratory.
He explained that the change would reduce risks to technical systems and national infrastructure while maintaining the link between world time and the Earth’s rotation.
The need for reform is due to the fact that atomic clocks count time with high accuracy, while the speed of the Earth's rotation changes under the influence of natural processes. Since 1972, 27 leap seconds have been added to synchronize world time with astronomical time. However, in the last decade, the Earth began to rotate faster. Because of this, for the first time, it may be necessary not to add, but to remove one second from UTC. According to experts, the probability of such an adjustment in the next ten years is about 30%.
Shemar recalled that even adding a second already led to technical problems. After adjusting the time in 2012, some servers froze and crashed. Deleting a second could be even riskier, he said, as some of the software has never been tested for negative leap seconds.
Earlier, the UK opposed the abandonment of leap seconds due to the historical connection of the time system with the Greenwich meridian. Russia also objected to the changes, fearing repercussions for the GLONASS satellite navigation system.
The Financial Times wrote last month about preparing to consider finally detaching the world-time standard from the physical rotation of the Earth. Markus Kuhn, a computer scientist at the University of Cambridge who opposes the idea of a leap hour, explained that a negative leap second should theoretically cause fewer problems than a positive one, since a computer clock would simply miss a second rather than add an extra one. “This should cause fewer disruptions because it does not violate the relative sequence of events with time stamps,” he said.
Astrophysicist Vladimir Surdin previously explained to RBC that satellite navigation systems use precise time to determine the location, so sharp adjustments can complicate their work. At the same time, physicist Nathan Eismont considered the fears exaggerated and noted that the transition would require additional technical work.
