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Unexpected acceleration of the Earth's rotation


SergUpstart
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On June 29, the Earth unexpectedly made a revolution around the axis 1.59 ms faster than 24 hours, and this became its fastest revolution since atomic clocks began tracking such data with great accuracy in the 1960s.
In recent years, the Earth's rotation has been gradually accelerating, but no one knows why this is happening. Since 2020, the planet has already broken the rotation speed record a couple dozen times, despite the fact that nothing like this had happened for decades before.
The Earth is not a perfect ball, so its rotation is constantly fluctuating, being subject to a variety of factors, including its internal structure, the tidal effect of the Moon, climatic changes. One team of scientists suggested that the acceleration of rotation may be due to fluctuations in the geographical poles of the Earth. This phenomenon was discovered in the XIX century by the American astronomer Seth Carlo Chandler, and is called the "Chandler oscillation of the poles."
According to Matt King, a professor at the University of Tasmania, a specialist in observing the behavior of the planet, this is really a strange phenomenon. Clearly something has changed, and it has changed in a way that has not manifested itself since the advent of precision radio astronomy in the 1970s.
If the days continue to shorten, scientists will have to subtract a second from the readings of the atomic clock. This will be the first case of a negative correction of the arrows in history. Since 1972, the scientific world has adopted the practice of adding an additional second, which is added to the coordinated Universal time (UTC) scale to align it with the average solar time UT1. So far we have only had to add these seconds, but not subtract them.
At the same time, scientists previously calculated that due to changes in the interaction of the Earth with the Moon in 6.7 million years, the day on Earth should become one minute longer.

It can be assumed that the core of the Earth cools and contracts, and then its rotation accelerates due to the law of conservation of angular momentum.

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Shortest recorded in the last ~50 years, but reconstructions show it was faster in the past, and we’ve gone to negative excess length of day in the atomic clock era. In the early 2000s ELOD was negative during part of the year. No leap seconds were inserted for 7 years. Then the days got longer again.

https://www.ststworld.com/understanding-day-length-fluctuations-what-they-are-and-what-causes-them/

Even with the fluctuations, you can see the long-term trend is toward longer days, and that we’ve had negative ELOD in the 1930s and a much larger dip from ~1860-1900

https://geodesy.geology.ohio-state.edu/course/refpapers/dLOD_1800-2000.pdf

Earth rotation rates have geologic- and climate-related contributions, so focusing on very short time scales is a tad misguided 

 

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2 hours ago, SergUpstart said:

Unexpected acceleration of the Earth's rotation

 

Thanks to swansont, +1, for pointing out the long term and statistical nature of the rotation.

Statistical fluctuations are, by definition, 'unexpected' in any specific fluctuation timing or quantity.

 

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