In 2020, the Earth has rotated so rapidly on its axis that the days are noticeably shorter. We might even have to turn back the clock soon to keep up with the rapid spin.
It seems a little contradictory. Where 2020 felt for most people a year that spanned indefinitely from crisis to shutdown and back again, the year actually zoomed in at record speed.
Or well: a timing technique anyway. After all, you and I would not notice much of a millisecond gain in the time we booked last year. However, this shorter rotation time of the Earth has been closely observed before International Earth Rotation Reference Systems Service (IERS)More than just a fun beverage. It affects the “world clock” setting in which we all live, the global standard on which all time zones are based.
Super sensitive atomic clocks
This UTC is also called UTC – not an acronym, by the way, but a compromise between the English term CUT (Coordinated Universal Time) and the French term TUC (Temps Universel Coordonné). UTC is in turn based on International Atomic Time, which is tracked using 400 super-sensitive atomic clocks, housed in 90 laboratories around the world.
“We have four of those hours,” says time manager Erik Dierikx of the National Standards Institute (VSL) in Delft. There, he closely monitors the IERS data, looking for the moment when UTC begins to deviate much from astronomical time.
Whereas when you think of 24 hours a day, the actual duration of one orbit around the Earth’s axis varies slightly every day, according to IERS data. This has a natural cause: changes in the wind, for example, or the flow of oceans. Even the motions of the Earth’s core have little effect on how fast the Earth is rotating.
To slow down
“Once the difference between astronomical time and UTC becomes very large, a leap second is added,” says Dereks, who then programs such a second into atomic clocks with his colleagues. “The last leap second was added on January 1, 2017,” he says.
For decades, the Earth appeared to rotate very slowly on average. But in the past year things have gone quickly, with remarkably short days. In fact, the shortest 28 days in books since 1960 are all from 2020, according to the e-commerce site timeanddate.com recently. Analysis of IERS data. Most Colorful Make it July 19th, by (Completed) One and a half milliseconds Less than 24 hours.
Negative leap second
Also this year, the Earth is expected to rotate around its axis relatively quickly, according to the IERS report In prediction, So astronomical time will continue to lag behind our clocks year-round in 2021.
Very cautiously, some tourists over time have begun to consider entering a negative leap second to turn the clock back on the line. Then we get only 59 minutes instead of 60 seconds, which evaporates one full clock mark from UTC books. This has never been done before.
“I think it will take some time before something like this becomes necessary,” says Dereks. But in theory this is definitely possible. Our gear can add seconds, but also erase. That’d be cool for one time.
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