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The International Earth Rotation Service

Do you know about The International Earth Rotation Service, and what do they do?

The fact is that there are two-time formats UT1 (based on the rotation of the Earth) and UTC (the format generally accepted by humanity associated with atomic clocks). In the 20th century, it was discovered that the rotation of the Earth slowed down, which means that there is a discrepancy in the accounting of time. To solve this problem, an additional (so-called bissextile) second was introduced in 1972. It is added on June 30 or December 31 in those years when UTC mustn't differ from UT1 by more than ± 0.9 seconds. Since then, it has already been announced 27 times. It is believed that on such days 23:59:60 goes after 23:59:59. In theory, it is also possible to subtract one second, but this has not happened yet.

The announcement of the bissextile second is one of the responsibilities of the IERS. They are based in Paris and are responsible for maintaining universal time.

It is impossible to predict changes in the Earth's orbital motion. 

But it is possible to consider the risks when planning the airline's crews - ensuring maximum robustness to the disruptions with the limited available resources is one of the essential functions of Rosterize.