Timekeeping is about to change forever

Key Points:

• The International Bureau of Weights and Measures is expected to vote to eliminate leap seconds from Coordinated Universal Time (UTC) starting May 20, 2027, replacing them with a leap hour to maintain alignment with astronomical time.
• Leap seconds, implemented 27 times since 1972 to sync atomic time with Earth's rotation, have caused disruptions in telecommunications, satellite communications, and global navigation systems, prompting tech giants like Amazon, Google, and Meta to advocate for their removal.
• Scientists argue that a leap hour, required only once every thousand years, would be less disruptive than leap seconds, which are difficult to implement reliably and can cause failures in critical infrastructure such as mobile networks and electricity grids.
• Despite the change, the link between UTC and astronomical time (UT1) will remain monitored and disseminated for applications like astronomy and celestial navigation, ensuring continued accuracy where needed.
• The decision aims to reduce risks to systems dependent on precise time synchronization, addressing challenges posed by irregularities in Earth's rotation, including the potential introduction of a negative leap second.