International Standards Group Votes to Kill the Leap Second

Credit: Erik Mclean/Unsplash

(Credit: Eric Mclean/Unsplash) Time can be tricky to measure, whether you’re rocketing through space at relativistic speed or just sitting on the surface of a spinning planet. Fifty years ago, scientists invented leap seconds to make sure clocks didn’t get out of sync with the Earth’s rotation, but there’s increasing pressure to do away with these snippets of added time. Now, the International Bureau of Weights and Measures (BIPM) has voted to kill the leap second — just not right this second.

Leap seconds were first implemented in 1972 to serve the same basic purpose as the leap days with which people are more familiar. A full solar year is slightly longer than a calendar year, so we add a day every four years to make up the difference. Leap seconds make up for the natural slowdown of the Earth’s rotation (well, usually). At the leap second’s inception, scientists added 10 of them; a further 27 have been tacked on in the years since. The goal is to keep the differential between Earth’s rotation and UTC to less than 0.9 seconds.

However, technologies like satellite navigation didn’t exist in the early 1970s, and computer networks were rudimentary compared with what we have today. There can be errors when two networks need to talk to each other but use different methods to account for leap seconds. Leap seconds have become a point of failure in computer systems, which can affect astronomical observations, aviation, financial transactions, and more.

Accurate time is essential to a whole host of technologies and industries, but our home planet just doesn’t cooperate.

The BIPM has come to agree with those who feel the current approach to leap seconds just isn’t worth the trouble. The vote, held in November 2022, means that leap seconds will no longer be added beginning in 2035. Of course, the planet’s rotation will continue to slow down, adding a minute to the rotational day in the next century. Instead of adding leap seconds on a continuous basis to maintain accuracy, these seconds will be added up and then added to the clock every century or so.

The average clock-watcher won’t notice any changes in their daily life — a second here or there barely registers on the most precise clocks in the world. Still, when 2035 rolls around, perhaps the computers we use to run our lives will break a little less often. Just remember to set your clock ahead one minute in 2135.

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