{"id":1656,"date":"2026-09-30T15:57:00","date_gmt":"2026-09-30T15:57:00","guid":{"rendered":"https:\/\/flatplanplus.io\/bbc-sciencefocus\/?p=1656"},"modified":"2026-09-30T15:57:01","modified_gmt":"2026-09-30T15:57:01","slug":"dangerous-experts-may-soon-have-to-delete-a-second-from-time-and-it-could-cause-chaos","status":"publish","type":"post","link":"https:\/\/flatplanplus.io\/bbc-sciencefocus\/2026\/09\/30\/dangerous-experts-may-soon-have-to-delete-a-second-from-time-and-it-could-cause-chaos\/","title":{"rendered":"‘Dangerous’: Experts may soon have to delete a second from time \u2013 and it could cause chaos"},"content":{"rendered":"\n
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TIME crisis<\/p>\n\n\n\n

\u2018Dangerous\u2019: Experts may soon have to delete a second from our clocks \u2013 and it could cause chaos<\/h1>\n\n\n\n

The Earth is spinning faster than usual, and it may make computers lose track of what time it is<\/p>\n\n\n\n

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By STEPH SANTOS PAULO<\/p>\n\n\n\n

–<\/p>\n<\/div>\n<\/div>\n\n\n\n

\"Picture
Credit: Getty<\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n\n\n

For more than half a century, scientists have been secretly messing with time. Since 1972, they\u2019ve added 27 extra seconds \u2013 known as leap seconds \u2013 to all our clocks, roughly once every year or two.<\/p>\n\n\n\n

This may sound like an elaborate prank. But these extra seconds kept our clocks in step with the Earth\u2019s rotation, which for decades was \u2013 ever so slightly \u2013 slowing down. Without them, our clocks would have slowly fallen out of sync with the Sun in the sky, by around a minute every century.<\/p>\n\n\n\n

The trouble is, computers hate leap seconds. Websites, power grids, and transport networks all rely on computers agreeing on the precise time, and a sudden extra second can throw them into glitchy chaos.<\/p>\n\n\n\n

If this sci-fi thriller plot sounds familiar, you may be remembering the \u2018Y2K bug<\/a>\u2019 where the whole world held its breath at the turn of the millennium, expecting the world\u2019s computer systems to suddenly break when the calendar switched to the year 2000.<\/p>\n\n\n\n

But now the planet has thrown timekeepers a curveball. Earth\u2019s spin has started speeding up \u2013 so much so that scientists think we may soon need, for the first time ever, a negative leap second: skipping a second rather than adding one.<\/p>\n\n\n\n

And according to experts, there\u2019s a chance it could cause chaos.<\/p>\n\n\n\n

\u201cA negative leap second poses a high risk of disruption to national infrastructure,\u201d says Dr Setnam Shemar<\/a>, principal scientist at the National Physical Laboratory\u2019s Time and Frequency Department.<\/p>\n\n\n\n

So, what exactly<\/em> would happen if we all lost a second of time? Could we just ditch leap seconds altogether? And, most importantly, who will actually decide what time it is?<\/p>\n\n\n\n

\"Neon
The Year 2000 (Y2K) problem, also known as the millennium bug, caused widespread panic about disruption it was predicted to cause for computer-reliant infrastructure all over the world. Credit: Getty<\/figcaption><\/figure>\n\n\n\n

Without a leap second, timescales would start to drift apart<\/h2>\n\n\n\n

Leap seconds may sound like an easily avoidable human-made problem, and that\u2019s partly because they are. <\/p>\n\n\n\n

The leap second was invented in 1972 as a compromise between two ways of measuring time. <\/p>\n\n\n\n

\u201cThe people who wrote the rule book for time decided that seconds should all have the same length defined by atomic clocks,\u201d explains Dr Markus Kuhn<\/a>, associate professor of computer science at the University of Cambridge.<\/p>\n\n\n\n

Atomic clocks, which were invented in the 1950s, keep time with frightening accuracy by monitoring the consistent frequency at which atoms absorb and emit radiation. <\/p>\n\n\n\n

They are much more reliable than the old-school timekeeping method: looking at the Sun\u2019s position in the sky. Time measured in this way can fluctuate depending on how fast the Earth is spinning, which affects where we see the Sun at a certain time of day. <\/p>\n\n\n\n

That\u2019s where the leap second comes in handy. <\/p>\n\n\n\n

\u201cThis additional second gets added every now and then, so that official time doesn\u2019t get out of sync with the rotation of the Earth,\u201d says Kuhn. <\/p>\n\n\n\n

This is the timekeeping system that the whole world has so far agreed to use. We call it Coordinated Universal Time (UTC). <\/p>\n\n\n\n

Thanks to this international agreement, a flight can take off in London at 08:00 UTC, and air traffic controllers around the world can all agree on exactly what that means.  <\/p>\n\n\n\n

If we decide to get rid of the leap second altogether, the world will start to shift in subtle ways.<\/p>\n\n\n\n

The Prime Meridian<\/a>, for example, a famous line that passes through Greenwich in southeast London, would lose its status as the reference point for UTC. <\/p>\n\n\n\n

\u201cThe line would start accelerating eastwards,\u201d says Kuhn. \u201cIn 600 years or so it will be about half an hour off, moving 7.5 degrees eastwards to somewhere near the French-German border.\u201d<\/p>\n\n\n\n

\"A
The Prime Meridian line at Greenwich in London divides the eastern and western hemispheres of the Earth, and marks the baseline of Coordinated Universal Time (UTC+0). Credit: Getty<\/figcaption><\/figure>\n\n\n\n

For astronomers, in particular, getting rid of the leap second would be a real pain. <\/p>\n\n\n\n

Standard clock times would no longer be tied to the motions of planets and stars, so would be of no use in helping them decide when and how to point their telescopes towards space. <\/p>\n\n\n\n

Ultimately, says Kuhn, those in favour of scrapping the leap second are likely to win this battle, simply because \u201cthere are far more computer practitioners worrying about these things than there are hobby astronomers\u201d.<\/p>\n\n\n\n

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Read More:<\/h3>\n\n\n\n