![]() ![]() ![]() He said the deletion of a leap second was also unlikely to affect technology that uses global positioning receivers - unless they were very old.īut software engineers at Meta (previously Facebook) say the deletion of a leap second is untested and could have "devastating" effects. "So you sort of go forward a bit fast, but you don't do anything that's against what you expect." "But probably won't happen for another 8 to 10 years at the current rate of drift." "Leap seconds are only now announced six months in advance, because trying to predict even further than that is very difficult," Dr Wouters says. With the way the Earth wobbles all over the shop, it is hard to predict when this may happen. "We've never had one of these deletion events before," says Michael Wouters, who is in charge of standards, and time and frequency at the National Measurement Institute. If the current rate of drift continues, we may need to delete a second in a few years. "I don't know if we are very much further along the lines of understanding what's going on, but I dare say there's probably something going on in the climate system or in the oceans." What impact will this have on us and our computers? "Given that changes in both of those things can be linked to mass moving around on the surface of the Earth, it's probably not a bad guess that those things are linked in some way," he says. ![]() Professor King is not sure whether the wobble is playing a role in accelerating the planet's spin. LoadingĪs well as speeding up its spin, Earth's axis has been doing some strange things over the past couple of years, Professor King says.Īs the spin increased, the wobble reached an historic minimum. Scientists believe the wobble is influenced by fluctuations of pressure on the seabed caused by changes in ocean circulation. "That's not to say that that's happening in this case, but it's certainly happening." What about the Chandler wobble?Ī similar phenomenon that some scientists have suggested could come into play is the "Chandler wobble" - the periodic movement of the position of Earth's axis at the poles by around 9 metres over about 430 days. "Given that Greenland melting is being driven by human-induced climate change, humanity is fundamentally changing the way in which Earth spins. Surface variations, such as melting ice on Greenland and Antarctica, or changes in ocean circulation, can affect Earth over a much shorter time frame. Rotation rate can be affected by movements below the surface, but these changes happen slowly over the milliseconds-per-century type of scale. "Clearly something has changed, and changed in a way we haven't seen since the beginning of precise radio astronomy in the 1970s."Įarth's spin is tracked using radio telescopes that measure how long it takes our planet to move in front of stars. ![]() "It's certainly odd," says Professor King, who uses satellite-mounted atomic clocks to map changes in Earth's shape, rotation and gravity. Just why Earth has suddenly started to spin slightly faster is a mystery, says Matt King of the University of Tasmania. "That's why the leap seconds are introduced to keep the atomic clocks and the astronomical clocks together."Īround 27 leap seconds have been introduced since the advent of atomic clocks, the last one in 2016.īut in 2020, the trend reversed as Earth clocked up 28 days that came in under 24 hours. "If you don't do anything about it, you are going to gradually get the seasons out of step with the calendar," Professor Watson says. ![]()
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