During perihelion, the Earth is about 147.2 million kilometers from the Sun. Photo: Teknoloji.

During perihelion, the Earth is about 147.2 million kilometers from the Sun. Photo: Teknoloji.

Since some years, Earth seems to be spinning faster than it used to, which generally translates into shorter days. So much so that the Earth experienced the shortest day in its history this summer: on June 29, 2022, the planet rotated completely in 1.59 milliseconds less than normal. And this July 26, the day lasted 1.50 milliseconds less, a more surprising and striking record than the previous one.

And it is that, during the last 40 days, Atomic clocks that measure the Earth’s rotation cycle have recorded the shortest days recorded since they began their work in the 1960s. However, if this trend is appreciated from the opposite point of view, it has been possible to glimpse that the spins have slowed down for millions of years, despite the fact that it was with an inconstant rhythm.

Scientific explanation

“That is due to the presence of the Moon. A nearby body, through its force of attraction, keeps a part of the energy that the Earth used to rotate”, exhibits Antonio Rius, a physicist at the CSIC, forcefully.

The deviation of 1.59 milliseconds is still so minute that it does not question the convention of the day, nor does it express any significant cosmic disorder. Reality has no commitment to all those idealizations that humanity has progressively built (hours, days, years…). For this reason, the Earth has always slightly deviated from the ‘commitment’ of 24 hours just.

This is because the poles dance in 433-day cycles in irregular circles between three and 15 meters in diameter, thanks to a pattern known as the “Chandler wobble” and known since 1891. The reason for this oscillation, according to a study from the year 2000, It is due to “the fluctuating pressure of the ocean floor, caused by changes in temperature and salinity, and by changes in the direction of ocean currents”.

hypotheses and theories

However, there are other theories that extend the certain knowledge of the “Chandler wobble”, such as the melting of glaciers, because the distribution of mass on the earth’s surface is changing, moving it from the poles to the center, what determines the fluctuation.

Another of the most contrasted hypotheses refers to the inner core of the planet, its solid center, which moves through the outer core, of liquid substance and alters the rotation. Finally, another theory is linked to the seismic movements that affect the wobble of the poles. What’s more, the current trend for short days has been linked to the 2004 Indian Ocean earthquake.

“There is an image that can explain it: that of a skater who turns on himself at a speed that is apparently constant but, in reality, depends on whether he raises his arms or lowers them, whether he bends down a little or not. If he lowers his arms, he turns faster than if he raises them… ”, assures Rius.

(Taken from AS)

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