Scientists Vote to End Leap Seconds, Severing Link Between Earth's Rotation and Digital Clocks

Scientists have voted to end the leap second, a decision that will sever the tight link between Earth's rotation and modern digital clocks in the largest shakeup for timekeeping in half a century. The International Bureau of Weights and Measures, or BIPM in French, made this move by majority vote today. They agreed to scrap the practice entirely.

When the leap second started back in 1972, scientists added twenty-seven extra seconds to Coordinated Universal Time, known as UTC, to keep our clocks locked exactly with the planet's spin. That era is over now. Moving forward, UTC and astronomical time, called UT1, are allowed to drift apart by up to one hour. That gap equals 3,600 seconds. Over a very long stretch of years, any clock set to UTC will slowly lose sync with the Earth's actual rotation. This means dawn, noon, and dusk could occur up to an hour earlier or later than your watch says they should.

The resolution passed at the General Conference on Weights and Measures meeting in Versailles, France. A majority backed it there. The change officially starts May 20, 2027, which happens to be World Metrology Day. Dr Setnam Shemar from the National Physical Laboratory told the Daily Mail that this is a good move overall. He noted that leap seconds have given way to what he calls a leap hour to protect systems relying on accurate time. Humanity keeps its connection to Earth's rotation, but it will be looser now.

Clocks started syncing to Greenwich Mean Time in 1884 and stayed that way for over a century without major issues. High-precision computing changed everything though. Today, atomic clocks measure time by counting tiny natural vibrations inside atoms, making them incredibly consistent. The Earth does not spin at a steady pace. Gravity from the moon and shifting ice caps at the poles cause it to wobble, speed up, and slow down. This creates small inconsistencies between lab clocks and the timing set by the sun overhead.

A delay of even one second is fatal for many modern systems. Data centres handling cloud computing use time synchronization to distribute work across different servers. Financial markets like high-frequency trading need precise timestamps to execute orders and create audit trails for regulations. Without this accuracy, things break. The shift allows these critical infrastructure pieces to function without constant manual adjustments, even if it means our civil time slowly detaches from the planet beneath us.

The Earth spins at a changing pace, which means its natural time slowly drifted away from Greenwich Mean Time over the years. To fix this mismatch, the 69 member states of BIPM, an intergovernmental group that sets measurement standards, voted to insert 'leap seconds' into the clock. This move kept Coordinated Universal Time and astronomical time in lockstep for a long stretch, yet it carried heavy downsides. The biggest issue is that throwing in an extra second throws off computer systems built with no expectation of such interference.

Dr Shemar noted that organizations struggled to put these changes in reliably. Timing glitches from software bugs hit data centres and networks hard. A leap second added in 2012 triggered widespread trouble, bringing some websites down completely. Reddit suffered a major outage lasting 40 minutes because the servers' precision timers got confused. LinkedIn went offline briefly, and Qantas flights faced delays. In 2016, Cloudflare customers saw outages or delays when their servers could not handle the shift.

Meta has spoken loudly about scrapping the leap second, calling them 'a major source of pain for people who manage hardware infrastructures' in a blog post. Scientists now worry they might need to add a 'negative leap second' by 2029, which could be far more disruptive than anything before it. Since 1971, experts added 27 leap seconds to keep Coordinated Universal Time aligned with astronomical time (UT1). Now, these clocks are allowed to drift by up to an hour without correction.

Usually, the Earth's rotation slows because of the moon's gravity. But in the mid-2010s, the planet began spinning faster, pushing engineers toward a point where they would have to subtract a second from UTC to balance things out. That meant setting every digital system back one second at once, something many machines could not do. Worry grew so much that engineers warned of a 'mini Y2K' event, echoing the panic over the Millennium Bug in 1999. Stopping that disaster was a key reason for letting UTC and UT1 pull apart by a wider margin.

Under the new plan, BIPM will only act when the gap widens enough to need a leap hour, though that won't happen for at least 1,000 years. Until then, systems using atomic clocks can keep following UTC without worry. Dr Shemar explained that the main gain is sparing global systems and national infrastructure from the chaos of wrongly applied leap seconds. The decision today clears up uncertainty for anyone in charge of time-dependent infrastructure around the world. Who wants their servers tripping over a clock adjustment?