Leap seconds can be positive or negative (never happened) and are irregularly announced up to two times a year. The wikipedia article on leap seconds[1] is wor

Leap seconds can be positive or negative (never happened) and are irregularly announced up to two times a year. The wikipedia article on leap seconds[1] is worth reading and has this[2] great figure showing the variations of day length over the years due to various astronomical factors. It also shows how these small deviations slowly desync UT1 and UTC (red line), and that this issue cannot be solved by a linear scaling. [1] https://en.wikipedia.org/wiki/Leap_second https://en.wikipedia.org/wiki/Leap_second [2] https://upload.wikimedia.org/wikipedia/commons/thumb/5/5b/Deviation_of_day_length_from_SI_day.svg/512px-Deviation_of_day_length_from_SI_day.svg.png https://upload.wikimedia.org/wikipedia/commons/thumb/5/5b/De...