With accurate astronomical calculations, scientists have recently figured out that the length of the day is gradually getting longer, thereby posing a possible impact on timekeeping, GPS tracking and other navigation technologies that people are now dependent on. From its very inception, the Earth’s rotation has been slowing down over the years due to friction effects due to the tides driven by the Moon; this accounts for addition of 2.3 milliseconds to the lengths of the days in each century.

Several research studies have unearthed that the average daytime a few billion years ago was only 19 hours. The precise speed of Earth’s rotation can be calculated since the 1960s when operators of radio telescopes across the globe started to devise techniques to simultaneously observe cosmic objects like quasars. Comparing these estimates and an atomic clock, scientists uncovered that the length of the day has been shortening in the last few years, mostly because of the tides and seasonal effects.

The Earth witnessed its shortest day on 22 June 2022. However, the trajectory of shortening has seemingly reversed towards lengthening since 2020 and the change has been unprecedented over the past 50 years. Scientists are still working on studies to figure out the reason for this change, which could possibly be the weather systems, or increase in the melting of ice sheets or any other phenomenon.

One speculation is that the sudden change in the Earth’s rotational speed can be related to the phenomenon called the “Chandler Wobble” – which is basically a small deviation in the Earth’s axis in a span of around 430 days. Another speculation is that there is no change within or around the Earth and the change in rotation speed can simply be due to long-term tidal effects working in parallel with other periodic processes.