Days on Earth get longer by 1.8 milliseconds every century, says a new study published in the Proceedings of the Royal Society A. The data gathered by the team shows that the spin was slowing down to a lesser extent centuries and centuries ago—3,000 years ago, it used to be only by 2.3 milliseconds per 100 years.
While we might perceive time as going faster and faster year by year, the opposite is actually happening, according to scientists. Our days on Earth are getting longer by 1.8 milliseconds every century. Granted, this is not much—we only have one minute more in 3.3 million years; that extra-25th-hour that you think you need will only come in 2 million centuries’ time.
This new estimate has been deduced from the deceleration in the rotation of the Earth—the UK-based team of researchers behind the finding purport that one day increases in length by approximately 1.8 milliseconds every 100 years. The new study challenges previous ones which had suggested it would take one century to have 2.3 milliseconds more daily: this means that the Earth is slowing down even more than it was initially theorised.
The updated data is based on early records of Greek, Chinese, European, and Middle-Eastern texts, and those preserved on tablets from Babylon that provide information about solar and lunar eclipses, and their location and time. This great variety of writings date from 720BCE to last year. These historical works were compared with a computer model that depicts the same events in a context whereby Earth’s rotation remains unchanged with the aim of determining the rate of the slowing down of the rotation of the planet. Unsurprisingly, a consistent difference was found between the two: the figures generated from the model were different from the real times and places when and where the eclipses are recorded to have been viewed, explains study-author, Dunham University’s Leslie Morrison.
“It means Earth has been varying in its state of rotation,” says Morrison.
The deceleration of our Earth’s spin is determined by a variety of factors. It is correlated with the Moon: the latter’s pull is dragging onto our planet, and its orbit is getting bigger as a consequence, by about 4cm every year. Furthermore, the slowing down is also brought about by our sea levels and the electromagnetic forces inside of the Earth.