Time Is Up for the Leap Second

Time goes by quickly, at least it seems that way. Did you know that in 2035 time will literally stop skipping ahead? That’s because the practice of adding a leap second, which is a theoretical second of time that has never actually happened, will end for at least 100 years. In November 2022, the General Conference on Weights and Measures — which is the international timekeeping body that determines global standards for measuring time — passed a resolution to let clocks run in the future without adding or subtracting time. Why were leap seconds added to our timekeeping process in the first place? The addition of a leap second here and there was meant to bridge the difference between measurements of atomic and astronomical time. The truth is, the earth doesn’t actually spin around its axis at the same rate in every 24-hour cycle, but our timekeeping devices track the same exact 24 hours in a day. The problem between our measure of timekeeping and the reality of time passing occurs because the earth’s rotation is rarely completed at the same rate as our 24-hour clock. In addition, natural disasters can cause the earth’s rotation to speed up or slow down. In fact, a series of natural disasters over the last several decades has caused the earth’s rotation to slow down. In addition, the sloshing of the oceans and the gusts of our winds can also slow down the earth’s rotation. After the first leap second was used to pad our global measurement of atomic time in 1972, only 27 have been added since — and they were only added at irregular intervals. The most recent leap second was introduced in 2016.