Recorded Earth Last year, 2020 recorded the fastest 28 days since 1960, when the Earth completed its rotation on its axis one millisecond faster than average, meaning that in 2020 time did not escape.
It is known that the rotation time on the Earth’s axis varies slightly due to atmospheric pressure, wind, ocean currents and the motion of the center of our planet, but it is difficult for international time controllers to use ultra-precise atomic clocks to measure the global time that each person sets his clocks.
When the astronomical time defined by the time it takes the Earth to complete a revolution about its axis deviates from UTC by more than 0.4 seconds, UTC is adjusted.
So far those changes have included the addition of a “leap second” at the end of June or December, corresponding to astronomical time atomic time.
These leap seconds have been used since the beginning of precise satellite measurement in the late 1960s and early 1970s as the Earth’s rotation has been declining, and since 1972 scientists have added an average of one and a half seconds each year.
Finally in 2016, on New Year’s Day 23:59 minutes 59 seconds was added to “Leap Second”.
Also, the latest acceleration of the rotation around the Earth’s axis made scientists talk about a negative leap (eliminating one second) for the first time, instead of adding one second, because the average length of a day is 86,400 seconds, but in 2021 an astronomical day will take 0.05 milliseconds. In less than 86,400 seconds, over a one-year period, it will add a 19m delay in atomic time.
If the speed of rotation around the Earth’s axis increases further, it will be necessary (except for a second), but it is too early to say that this will happen.
There are also international discussions going on about the future of leap seconds, and the need for a negative leap second may push the decision to end leap seconds forever.
The Earth’s rotation around its axis in 2020 was faster than usual because it broke the previous record for the shortest astronomical day occurring 28 times in 2005, and on July 5, the shortest day of the year, the Earth’s rotation was 1.0516 milliseconds 86,400 seconds, the shortest day in 2020. On July 19, the Earth completed a revolution of 1.4602 milliseconds faster than 86,400 seconds.
In general, leap seconds have their advantages and disadvantages. Astronomical observations can be useful to ensure that they are synchronized with the clock time, but this can be a problem for some data recording applications and communication infrastructure.
Therefore, some scientists from the International Telecommunication Union have suggested that the gap between astronomy and atomic time extension be left until it becomes necessary to add a “leap hour”, which minimizes communication disruptions, and if that happens, astronomers will have to make their own changes at that time.
Historically, time has been based on the rotation of the earth on its axis with respect to celestial bodies, but with the invention of atomic clocks, time is more accurately presented.
In 1970 international treaties established a system for measuring global time and Earth’s rotation in space, and the International Commission on Earth’s rotation and reference systems was the body that monitored the difference between the two systems and officially announced the flow by removing it from global time when necessary. To keep the difference between the two within 0.9 seconds, it is not yet planned to add new jump seconds.
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