Scientists said that last year (in 2020) the speed of the Earth's rotation on its axis was "slightly higher" but there is nothing to worry about because this increase was very small, on a scale of one thousandth of a second (milliseconds).
According to the Time and Date website, last year recorded 28 days when the Earth completed a full cycle on its axis in about one millisecond earlier. We can’t notice this change in the duration of "one day" at all, but the difference can be noticed by the highly sensitive atomic clocks.
Atomic clocks began to record time with great precision in 1960, after which we learned that the speed of ground axial rotation fluctuates very little. Extremely accurate measurement of time is also essential for the proper operation of satellites.
The shortest day of the previous year was July 19, 2020, which was 1.46 milliseconds less than the average length of a day, while the longest day of 2020 was April 8, which was 1.62 seconds longer than the average. It should be noted that the earth completes one revolution on its axis every 86,400 seconds (24 hours) which we call "one day" in common phrasing.
However, due to changes in atmospheric pressure, winds, seawater flow and changes in the movement of the ground core, there is a slight decrease in this period, which is on a "millisecond" scale.
Atomic clocks measure time up to one billionth of a second. That is, the rate of accuracy is so high that atomic clocks differ by only one second in the measurement of time about 100 million years later.
For this purpose, the International Earth Rotation and Reference Systems Service (IERS) has been established at France in 1988. With the help of thousands of observatories around the world, it keeps track with the help of nearly 200 sensitive atomic clocks.
Experts believe that this series of faster axial rotations of the Earth will also continue this year (in 2021).
It will be interesting to read that due to the slightly slower axial rotation of the Earth, the measurement of the day has been corrected by adding "one leap second" 27 times in the last 48 years. If the Earth continues to rotate faster than usual for many years to come, it may be necessary to reduce the day's measurement by one leap second, but this is not immediately possible.
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