Atomic clocks, combined with precise astronomical measurements, have revealed that days tend to get longer, scientists reveal.
This has a critical impact not only on our timekeeping, but and on things like GPS and other technologies that govern our modern lives.
In recent decades, the rotation of the Earth on its axis has accelerated. This trend has made our days shorter. In June 2022 we set a record for the shortest day in the last half century.
Despite this record, the steady acceleration curiously turned into a slowdown: the days are once again longer, and the reason is so far a mystery to scientists.
Scientists are trying to answer this question: why is the Earth’s rotational motion slowing down again?
Since the 1960s, when radio telescope operators around the planet began developing techniques to simultaneously observe cosmic objects such as quasars, we have had very accurate estimates of the Earth’s rotation speed.
The reason for this change is not clear. It could be due to changes in weather systems or excessive melting of the ice sheets, although they have not deviated much from their constant melting rate in recent years.
Could be related, also by the violent eruption of the volcano in Tonga which injects huge amounts of water into the atmosphere? Probably not, given that this happened in January 2022.
Scientists have speculated that this recent and mysterious change in the planet’s rotation speed is related to a phenomenon that refers to a small deviation of the Earth’s rotation axis over a period of about 430 days.
Furthermore, it could just be long-term tidal effects working in parallel with other periodic processes to to produce a temporary change in the Earth’s rotation rate.