Over the centuries, our planet rotates slower and slower. Very slowly, the days on Earth are getting longer. 1.4 billion years ago, a day lasted only 18 hours and 41 minutes. Today, researchers from the Technical University of Munich (TUM) have been able to measure the Earth's rotation speed more accurately than ever before. They are able to determine when we can enjoy a 25-hour day.
The length of the day fluctuates
During its journey through space, the Earth rotates on its axis at slightly varying speeds. Furthermore, the axis around which the planet rotates is not completely fixed; It rocks a little. This is because our planet is not completely solid, but is made up of different elements, some solid and some liquid. Therefore, the interior of the Earth is in constant motion. These differences in mass affect the planet's rotation rate.
Thanks to the ring laser of the Wettzell Geodetic Observatory, these differences can now be measured very precisely.
Ring laser to measure the Earth's rotation speed
The Wettzell ring laser has been continuously improved by TUM researchers since its introduction. The new correction algorithm allows the instrument to measure the Earth's rotation with an accuracy of 9 decimal places, which corresponds to a fraction of a millisecond per day. The observed upward and downward fluctuations reached values of up to 6 ms over a period of approximately two weeks.
What are ring laser measurements used for?
The measurements will be used to determine Earth's position in space. It will also benefit climate research and make climate models more reliable.
“Rotational fluctuations are not only important for astronomy, they are also urgently needed to create accurate climate models and better understand weather phenomena such as El Niño. The more accurate the data, the more accurate the predictions are,” explains Professor Ulrich Schreiber, who led the project at the University Observatory. Technical Munich (TUM).
When does a day have 25 hours?
The length of daylight on Earth has gradually increased over time. In the time of the dinosaurs, a day lasted only 23 hours, and 1.4 billion years ago it was only 18 hours and 41 minutes.
According to predictions, a day will last 25 hours in 200 million years, but that is still a long way off.
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