La rotation de la Terre s’accélère, et elle vient de battre un record

La rotation de la Terre s'accélère, et elle vient de battre un record

This unseen trend for the general public is not always easy for network administrators to manage.

This is a detail that may surprise some, but the speed of the Earth’s rotation is not perfectly fixed; varies very little over time. On June 29, in an article discovered by Popular MechanicsNational Physical Labs (NPL) researchers announced that this day had been the shortest on record since the invention of the atomic clock in the 1960s.

This measurement is based on records from the International Earth Toration and Reference Systems Service (IERS). It is an institution that is responsible for collecting, validating and redistributing a large amount of data on the rotation and orientation of the Earth.

Very different trends in the short and long term

As a general rule, if we reason on very long time scales, well beyond human lifetimes, our planet’s rotation slows down ever so slightly. It is simply a well-known consequence of its gravitational interaction with the Moon and the Sun. Article published in the prestigious magazine Sciences explains for example that the rotation of our cradle has slowed down about 6 hours in the last 2740 years.

But the IERS calculations show that the short-term trend is quite different, and even diametrically opposite. On June 29 it dropped by 1.59 milliseconds. compared to the commonly accepted 24 hours. And this is not an isolated incident. According to the specialized site, this record had already been broken 28 times in 2020, with an estimated delay of -1.47ms. This dynamic has continued to increase ever since, with new surveys in -1.50ms on day 26 June, then to -1.59 ms three days later. These values ​​have been compiled in the following graph.


It well illustrates the variability of this parameter, but also the trend that it currently follows on our scale; Despite annual and seasonal variations, it is clear that the average length of the day decreases over the years – and therefore the Earth rotates faster and faster.

A little known phenomenon

The origin of this strange variation remains to be explained… and at the moment, researchers are still skeptical. Even experienced geologists swap hypotheses on the fly on Researchgate, a very popular portal among researchers.

Some suggest that it may be a consequence of the internal geodynamics of the Earth. Others believe that it is rather necessary to be interested in its orbit and its relationship with neighboring celestial bodies to complete this file. But as it stands, it doesn’t exist yet. no consensus

But even if the question is obviously worth asking, the answer is not particularly important outside the framework of basic research. The consequences of these gear changes, on the other hand, are much more so.


Indeed, to offset the effect of the long-term slowdown described at the beginning of the article, the international community has agreed to introduce a system of ” leap seconds “. Since 1972, 27 seconds have been added to the universal standard, Coordinated Universal Time.

This approach has worked well so far; but if the Earth’s rotation speeds up significantly, this sleight of hand could well become problematic. In fact, a considerable part of the specialists believe that this time it would be necessary to introduce a “negative leap second” to cushion this recent acceleration. A prospect that already terrifies some professionals

Concrete consequences for networks

The problem is that time management is an absolutely crucial component of modern networks. They are largely based on what are called “time stamps”, a kind of virtual buffers that certify the date and time of an operation.

If these timestamps are incorrect, it can cause major problems with synchronization, authentication, archiving, and more. The Windows Server documentation has a dedicated page to support this issue.

© Igor Son – Unsplash

In a blog post, two Meta employees gave their point of view on the matter. They explain that whenever one of these leap seconds has been introduced, system engineers and administrators have faced this type of problem. ” They have caused problems throughout the industry and continue to present many risks. “say the authors of the post. “ Devastate the community every time “, they lament.

Therefore, the authors argue in favor of a definitive blocking of the current 27 leap seconds. They also explain that it would be more appropriate to look for a new system that would compensate for these fluctuations without turning all computer systems upside down. Therefore, it will be interesting to see how the industry will respond to this problem and to follow the evolution of the rotation speed of the Earth.

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