Why is this happening and what consequences – even serious – could it have?
There are facts that we take as a basis – such as the fact that a day consists of exactly 24 hours: that is, our planet takes a lot of time to rotate on its axis. However, in reality, this rotation speed is also not constant, and in general – perhaps surprisingly given the title of this article – the rotation of our planet is slowing down. Every century, it takes the Earth a few milliseconds or more to make one complete revolution (1 millisecond is 0.001 seconds by definition). However, in recent years something has changed and the Earth is spinning faster and faster, to the point that since 2020, records for the exact length of a particular day have been since atomic clocks were broken.
And recently, the mentioned record was broken on June 29 of this year: on this day, the Earth completed a complete revolution in less than 24 hours with 1.59 milliseconds – timeanddate.com reports. Of course, as the length of the day increases, the Earth rotates slower. When it decreases and becomes a negative number compared to 24 hours, the Earth rotates faster.
Thus, the current record fits with the trend that the planet’s rotation has accelerated in the past two years – the 28 shortest days on Earth were recorded in 2020, since accurate daily measurements using atomic clocks began in the 1960s. That year, the record holder was on July 19, which was – 1.47 milliseconds shorter than 24 hours. The pace didn’t slow down in 2021 either, although that year’s record was a little longer than in 2020. This year, the 2020 record was broken by 0.12ms. But that 2020 record was broken again, on July 20, when that specific 24 hour period was shortened by 1.50 milliseconds.
The reason for this change is also not clear to researchers – it may be the result of processes occurring in the outer or inner layers of the Earth, and it may be related to changes in the oceans, tides and even the current climate. The researchers themselves are unsure, and they can’t really predict how long a day will be more than a year in advance. However, one of the reasons may be a change associated with a phenomenon called Chandler wobble – the chandler wobble is the periodic rotation of the Earth’s rotation axis around a central axis, that is, a kind of oscillation of the axis around which the planet revolves, and therefore any rotation determines the length of the day. All this can be understood as a small irregular movement of the geographical poles of the Earth on the surface of the planet – this oscillation usually ranges between 3-4 meters.
But what’s interesting is that Chandler’s bobbing stopped between 2017 and 2020.
OK, but what happens if this faster spin continues for an extended period of time? In this case, it is possible to introduce a negative “leap second” for the first time in history. This would be necessary in order to keep civil timing – which relies on the highly accurate timekeeping of atomic clocks – in line with solar time, which depends on the movement of the sun across the sky.
Introducing a negative “leap second” in practice means that our clocks will skip a second, and this can cause problems in our IT systems. Of course, the question is whether this step will ever take place. According to experts, there is a 70 percent chance that we ever hit the negative record, and a leap second wouldn’t be needed.
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