Scientists, baffled to find that the Earth rotates faster and faster

For a few years now, the Earth seems to be spinning faster than it used to, which translates into shorter days. The phenomenon has reached the point where, in the last two months alone, several days with a duration of less than 24 hours have already been measured, and all without scientists being able to explain why. Last June 29, for example, was the shortest day recorded since atomic clocks began to be used to measure the Earth’s rotation in the 1960s. On that day, our planet was 1.59 milliseconds short of the usual 24 hours. And the same thing was repeated on July 26, with a new acceleration of 1.50 milliseconds that almost managed to beat the previous month’s record. The reason is unknown. What is happening? According to the most widespread opinion, the rotation speed of the Earth should be getting slower. And in fact it is, if we consider long periods of time. With each passing century, for example, the Earth takes about a couple of milliseconds longer to complete each rotation. But within this general pattern, the speed of the Earth’s spin fluctuates, and since 2020 the speed records have been one after another. As explained on timeandate.com, during these last two years the shortest 28 days of all those measured since the 1960s have been recorded. The causes of this sudden acceleration of the Earth’s rotation are not clear, and to try to explain it, scientists they shuffle from geological processes in the inner layers of the planet to the action of the oceans, the tides or even the climate. Speaking at the annual meeting of the Asia-Pacific Society for Geosciences in Singapore this week, Leonid Zotov, along with his colleagues Christian Bizouard and Nikolay Sidorenkov, have suggested that the current decline in day length might have something to do with with the so-called ‘Chandler wobble’, a small irregular movement of the geographical poles of the Earth along the surface of the globe. “The normal amplitude of the Chandler wobble is about three or four meters at the Earth’s surface,” Zotov told timeandate.com, “but from 2017 to 2020 it disappeared.” According to numerous readings carried out with atomic clocks since 1973, in general the Earth’s rotation is slowing down. So much so that to compensate for that slower spin, caused in part by the Moon’s gravitational ‘pull’, the International Earth Rotation and Reference Systems Service (IERS) has long been adding occasional ‘leap seconds’, the last of them on December 31, 2016. The consequences of the acceleration But if the current episode of acceleration continues, it may be necessary, for the first time in history, to introduce a ‘negative scalar second’, which implies that our clocks would have to ‘skip’ a second, with important consequences for GPS and communications systems. The acceleration of the Earth’s rotation has consequences because the atomic clocks used in GPS satellites do not take into account the changing rotation of the planet. And if the Earth rotates faster, it means that it will arrive at the same position as the day before a little earlier. Half a millisecond of difference is equivalent, in Ecuador, to a distance of 26 cm. Therefore, the 1.50 milliseconds measured on July 26 represent a difference of 78 cm. Enough to make GPS systems virtually useless. The introduction of the second negative could solve the problem, although it would also affect the computer systems. The reason is that clocks typically go from 23:59:59 to 23:59:60 before resetting at 00:00:00. But a negative leap second would cause the clock to change directly from 23:59:58 to 00:00:00, which some analysts say could have a “devastating effect on software that relies on timers.” MORE INFORMATION The organs of a pig are ‘resurrected’ one hour after its death A micrometeorite causes “uncorrectable changes” in the main mirror of the James Webb What to do in this situation? For now, the only solution is to continue monitoring the Earth’s rotation to see if the acceleration continues or if it is just a passing episode. Only then will it be time to make concrete decisions.