RTL Today – Ever shorter days: The Earth is spinning faster than usual, should we be worried?

The Earth is spinning faster than usual. Scientists evoke a difference of the order of a millisecond, or a fraction of a second, corresponding to a thousandth of it. This is nothing to worry about, but the phenomenon is still closely monitored.

On Wednesday June 29, 2022, the Earth completed its full rotation on itself in less than 24 hours, exactly 1.59008 milliseconds ahead. A day is in fact very rarely made up of 24 precise hours. 400 million years ago, a full rotation was completed in 22 hours.

Véronique Dehant, geophysicist, Royal Observatory of Belgium, develops these variations: “At present, the variation in the rotation of the Earth is a few tenths of a millisecond and what we have seen recently is that we have reached a kind of significant excursion of the order of ‘1.6 milliseconds and that’s what happened in June.”

Several elements influence the speed of rotation of the Earth on its axis. First of all, there are the atmospheric conditions, including the wind.

Véronique Dehant illustrates this example: “When the wind comes to push on one side of a mountain stronger than on the other side of the mountain, we change the rotation of the Earth.”

There are also the tides, the melting of the ice, all the movements of the water and the oceans. The main factor lies under our feet: the movements of the molten liquid iron that make up the earth’s core.

“We have this liquid core that pushes on the topography, the bumps and the pits at the interface of the core and the mantle and that changes the rotation of the Earth”, describes the geophysicist.

On the scale of a human life, a shift of 1.6 milliseconds per day, after 80 years, this gives a difference of 45 seconds.

Until 2016, the Earth was spinning a little too slowly and then, seven years ago, it started to speed up. Why was there this change? Scientists don’t have an answer.

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