Credit: NASA/EPIC, edit by Tdadamemd @ Wikipedia
When they say ‘shifts’ they’re measuring in milliseconds or even smaller units of time. Physics Today says ‘The new measurements are relevant to understanding the global water cycle and atmospheric circulation and may provide an important constraint on the effect of all those processes together.’
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Researchers at the Technical University of Munich (TUM) have succeeded in measuring the Earth’s rotation more exactly than ever before, reports Phys.org.
The ring laser at the Geodetic Observatory Wettzell can now be used to capture data at a quality level unsurpassed anywhere in the world.
The measurements will be used to determine the Earth’s position in space, benefit climate research, and make climate models more reliable.
Care to take a quick step down to the basement and see how fast the Earth has been turning in the last few hours?
Now you can at the Geodetic Observatory Wettzell. TUM researchers have improved the ring laser there so that it can provide daily current data, which until now has not been possible at comparable quality levels.
What exactly does the ring laser measure? On its journey through space, the Earth rotates on its axis at slightly varying speeds. In addition, the axis around which the planet spins is not completely static, it wobbles a bit. This is because our planet is not completely solid, but is made up of various component parts, some solid, some liquid.
So, the insides of the Earth itself are constantly in motion. These shifts in mass accelerate or brake the planet’s rotation, differences which can be detected using measurement systems like the TUM ring laser.
“Fluctuations in rotation are not only important for astronomy, we also urgently need them to create accurate climate models and to better understand weather phenomena like El Niño. And the more precise the data, the more accurate the predictions,” says Prof. Ulrich Schreiber, who led the project at the Observatory for TUM.
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Device measurements are significantly more precise
The device can use this new corrective algorithm to measure the Earth’s rotation precisely down to 9 decimal places, corresponding to a fraction of a millisecond per day. In terms of the laser beams that’s equivalent to an uncertainty starting at only the 20th decimal place of the light frequency and stable for several months.
Overall, the observed up and down fluctuations reached values of as much as 6 milliseconds over approximately two weeks.
The improvements in the laser have now made significantly shorter measurement periods possible as well. The newly developed corrective programs let the team capture current data every three hours.
Full report here.
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Nature article: Variations in the Earth’s rotation rate measured with a ring laser interferometer
via Tallbloke’s Talkshop
November 12, 2023 at 06:09AM
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