Earth has turned faster and scientists reveal an invisible but global phenomenon!

The earth rotated 1.33 milliseconde earlier than usual on Tuesday, August 5. It was one of the shortest days of 2025, with a period of 86,399,9,9867 seconds. How does it happen, and how can we even measure it with such precision? It could make you dizzy.

On average, the earth performs physical rotation in 23 hours, 56 minutes, 4 seconds and 90.5 milliseconds – this is called a sidereal day. It is the “real” rotation of the earth in relation to distant objects of distant space, like the stars.

However, most people live a day of 24 hours, called solar day. This is the time elapsed between two sun levers, or consecutive lids. The additional 4 minutes come from the fact that the earth must make an additional rotation of a degree, or 361 degrees, so that the sun reappears in the same place.

Sidereal day against solar day. © Interplanetary

The two types of days are slightly shorter on August 5, 2025, largely because of what is happening with the ventsvents in theatmosphereatmosphere terrestrial, the circulation of fluids in the ocean and magmamagma – and even the gravitational attraction of the moon.

The differences compared to 24 hours have been precisely measured since the 1970s thanks to atomic clocks and astronomy. During a year, these variations accumulate: in 1973, for example, the sum of the differences amounted to +1,106 milliseconds, which means that the earth had a little more than a second on its rotation. In the same year, secondary seconds were introduced to correct this discrepancy, adding a second to the clock at the end of the day, or 23 h 59 min 60 s.

Determination of time by the stars, the sun and the moon

Time measurement requires disproportionate precision. THE positioning systemspositioning systems global (more commonly called GPSGPS) can locate you in space, without problem. But if the surface of your planet has shot slightly faster or more slowly than expected that day, an unlikely GPS will not know and your position will not correspond to that of your card.

A difference of 1.33 milliseconde translates into a position error of approximately 62 cm at theequatorequatortherefore the cumulative drift of 1973 would have caused GPS errors of about half a kilometer if it had not been corrected during the year.

Why does the earth not remain motionless?

To determine the vitessevitesse of rotation of the earth, you must find a repositoryrepository Where, ideally, nothing moves. Everything in space moves in relation to everything else, but the more we look far, the more things seem motionless; Just as distant hills seem to slow down on a train, and neighboring farms parade at full speed.

Fortunately, there are so beautifully shiny objects that they eclipse galaxiesgalaxies whole. These are the Quasars, visible throughout theuniverseuniverse to billions oflight yearslight years.

THE quasarsquasars are supermassive black holes whose massemasse can reach billions of times that of our sun, which emit between 100 and 10,000 times more light than our whole galaxy, the Milky WayMilky Way. Detectable for billions of light years in the universe, where everything is practically motionless, the Quasars act like cosmic beacons.

THE RadiotelescopesRadiotelescopes measure our position in relation to the latter, providing values of the rotation periodrotation period real of the earth with precision lower than millisecond.

These ultra-precise observations also serve as starting pointstarting point to computer models that take into account movementsmovements atmosphere, oceans, AstresAstres And many other phenomena to predict the duration of the day. This is how we know in advance when one day is shorter and we can correct the GPS accordingly.

The winds in the earthly atmosphere are those which influence the duration of the day most, due to their collisions with the earth’s surface, especially when they hit mountain chains. As incredible as it may seem, the wind thus slows down the rotation of the earth.

The prevailing winds of the earth are the fastest in winterwinter in thenorthern hemispherenorthern hemispherebut the slowest from June to August, so that the summer months always bring the shortest days of the year (even if we tend to say that these are the “longest” days in the northern hemisphere, due to their greatest duration of daylight).

These daily and seasonal variations are only short upheavals at the heart of wider slowdowns. For decades, the sourcesource of the polar capspolar caps slows down the rotation of the earth. To understand why, imagine a ballerina that turns and retracts her tense arms: she starts to turn much faster. A bullet that turns, like the earth, is no exception.

The measurement of universal time threatened by climate change!

The earth is flattened, which means that its surface at the equator is 21.5 km more distant from the center of the planet than its surface with the poles. With the melting of polar ice caps due to climate changeclimate changethe cast iron moves from the poles to the equator via The ocean. The elevation of the sea level removes water from the surface and, like the ballerina which spreads its arms, it contributes to the slowdown of the earth. The redistribution of the terrestrial mass modifies our rotation in a similar way, in particular by earthquakes.

The moon, although magnificent, can be a considerable obstacle for billions of years. The terrestrial oceans are raised by the severityseverity lunar, but during the rotation of the earth, these oceans are slightly in front of the moon on its orbitorbit. However, the moon continues to exercise a traction on these oceans, causing them back, against the anti -hosa rotation of the earth, which slows us down.

L’energyenergy of rotation of the earth is not lost, it is transferred to the moon, which gains speed orbitalorbital And allows it to escape a little better from earthly gravity. This is why it moves away from us 3.8 cm per year. The duration today has increased, going from 17 hours 2.5 billion years ago to 5 p.m., largely due to the reduction of the angular moment of the earth by the moon over the eons.

The rotation of the earth has slowed down each year from 1973 to 2020 (where precise measures exist), each year accumulating hundreds of milliseconds of shift, already offset by the addition of 27 seconds intercalary. The situation has changed from 2020: the earth began to turn faster instead of slowing down each year, probably due to an angular moment exchange between the terrestrial nucleus and the coat, but modulated by the many other movements that we have explored.

On July 5, 22 and August 5 were designated as among the fastest days of the year, because, in addition to the internal movements of the earth and the seasonal variations of the atmospheric winds, the position of the Moon in orbit also slows down the earth twice by orbit (every two weeks). Indeed, when the moon is directly above the equator, all its tidal forcetidal force Acts from east to west, but on these dates, it is positioned in the extreme north and south, which attenuates this effect.

You will not notice that the sunrise arrives 1,33 millisecond earlier, but thanks to atomic clocksatomic clocks of precision and astronomical measures referenced by the Quasars, this will be obvious.

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