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.
. . .
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
Tallbloke's Talkshop 
“the laser functions completely independently and doesn’t require reference points in space.”
“Each side of the ring laser in the basement of the Observatory in Wettzell measures four meters. This construction is then anchored to a solid concrete column, which rests on the solid bedrock of the Earth’s crust at a depth of about six meters. This ensures that the Earth’s rotation is the only factor impacting the laser beams and excludes other environmental factors.”
Here all this time I’ve been of the persuasion there is no such thing as an absolute reference. Just what IS the calibration reference?
Since they are measuring the beat note of presumably “identical” lasers, isn’t that a differential measurement, like everything else? What is also known since the 1950s is the gravimetric field intensity of the Earth varies by location and velocity, such that any atomic processes (decay or oscillation) will vary depending on the strength and differential velocity within the field. Would it not be prudent to include the effects of the phase delay and variability between the Earth’s mass and the gravity field it is immersed in? How do they know the two ring lasers are identical?
Witchcraft if you ask me.
“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.”
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Confirming lack of accuracy in climate models. What might the readings tell them about El Niño? 🤔
Length of day has been measured accurately with Atomic Clocks, officially, since 1972.
http://www.nist.gov/pml/div688/grp50/leapsecond.cfm
Less leap seconds have been added each decade since 1972.
This means Length of Day has decreased, earth is spinning faster, there is more ice near the spin axis and less water in the oceans around the equator.
I left out one word:
Less leap seconds have been added each decade since 1972.
[mod] updated
“Confirming lack of accuracy in climate models.”
So “climate models” involve measurements to nine decimal place precision…
Riiigggghtttt….
This device will generate a plenty of doomsday data.
Quote “up and down fluctuations reached values of as much as 6 milliseconds over approximately two weeks”
That is half the moon’s cycle. There are several years of records indicating the trend changes with new or full moon. It would be interesting to find the change when Jupiter and Venus are near/conjunction.
So how do they know it’s accurate?
Abstract:
We employ an inertial self-contained measurement technique based on an optical ring laser interferometer rigidly strapped down to the Earth’s crust and operated in the Sagnac configuration. This large-scale gyroscope integrates over three hours for each data point, as opposed to an entire global network of Global Navigation Satellite Systems receivers and Very Long Baseline Interferometry that can only provide a single measurement per day.
So there 🤓
More funding required please.
Harmonics: I have a fair understanding of most things Physical ( Physics was Fun) Real Engineering is better ( apart from the Maths – the dreaded Calculus) but so far as I can ( not) see, has anyone discussed the technicalities of Harmonics of this System ?
oldbrew says:
The usual idiotic comments from the dumb blokes. Just the model I have been pushing and had published years ago.
The usual charm from @whut 🙂
Talkshop 2014…
More recently (2020)…
ESD Ideas: Long-period tidal forcing in geophysics — application to ENSO, QBO, and Chandler wobble
Paul R. Pukite
Click to access esd-2020-74.pdf
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See also here:
Unified Model of Earth Dynamics
OCTOBER 11, 2023 / PAUL PUKITE (@WHUT)
Ocean Tides and dLOD have always been well-understood, largely because the mapping to lunar+solar cycles is so obvious. And the latter is getting better all the time — consider recent hi-res LOD measurements with a ring laser interferometer, pulling in diurnal tidal cycles with much better temporal resolution. [bold added]
Geologist James Kamis says:
‘Pay special attention to the portion of the video animation that speaks to “temperature variations” from normal. You will hear the narrator say that El Ninos are sourced from a deep-ocean area.’
https://climatechangedispatch.com/triple-la-ninas-show-why-all-climate-models-are-flawed/