Clock ticking for leap second: Why timekeeping could change forever

The world’s timekeepers are meeting on Thursday near Paris to decide whether to scrap the “leap second”, which could disconnect the clocks we use from the Earth’s rotation and realign timescales. The world’s clocks are designed on the idea that the Earth completes one rotation on its axis in exactly 24 hours. But it actually wobbles, making the time the Earth takes to rotate less exact. And over time, the Earth’s rotation is gradually slowing. To compensate for that, since 1972, timekeepers have added a leap second every few years – the last one was added in 2016 – to keep clocks and Earth’s rotation in synchronisation.