Tides and Local G: Investigating the Relationship Through Long-Term Observations

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    gravity local tides
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Discussion Overview

The discussion revolves around the possibility of determining a local value of gravitational constant (G) by analyzing tidal observations over an extended period. Participants explore the relationship between tidal height variations and local gravitational effects, considering both theoretical implications and practical challenges.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Jeff Evarts proposes that tidal height might exhibit a normal distribution with measurable deviations that could relate to local G, suggesting this could be a viable research topic.
  • Another participant expresses skepticism about the feasibility of this approach, citing the complexity of tidal predictions which involve numerous confounding variables such as atmospheric conditions and ocean dynamics.
  • A suggestion is made that accurate pendulum clocks are necessary to detect tidal variations, indicating the precision required for such measurements.
  • Further technical details are requested, including references to relevant literature on tidal prediction and the limitations of high precision in tidal measurements.
  • Concerns are raised about the influence of solid Earth tides and the challenges posed by GPS accuracy in establishing reference levels for tidal measurements.

Areas of Agreement / Disagreement

Participants exhibit differing views on the viability of using tidal observations to determine local G, with some expressing skepticism about the approach due to various confounding factors, while others are open to exploring the idea further.

Contextual Notes

Limitations include the potential for confounding variables in tidal measurements, the need for high precision in timing, and the challenges of establishing accurate reference levels due to environmental factors.

Who May Find This Useful

Researchers and students interested in gravitational studies, tidal mechanics, and the interplay between celestial phenomena and local gravitational variations may find this discussion relevant.

JeffEvarts
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It occurs to me that it might be possible to determine a local value of G by observing the tides over a long-ish period. Tide height might be distributed as a normal curve, but it might have a measurable deviance. I wouldn't expect a left/right offset of the X coordinate based on G(local) , but perhaps an asymmetry across the mean X. Seems like a likely candidate for a paper, anyway. Anyone got a pointer to a study/thesis/paper on tides-vs-local-G?

-Jeff Evarts
 
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I do not like your chances.
Tidal changes in sea level are predicted by the synthesis of well over one hundred Fourier terms of solar and lunar terms. I believe that there are too many confounding variables, such as movement of the sand on the sea floor, wind, atmospheric pressure and ocean water temperature.

Only with a very accurate pendulum clock can you see tidal variation in the period of the pendulum. That is how you identify the best pendulum clocks.

Would you like a reference to a book on tide prediction?
 
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Can you better describe your idea?

Get a copy of; "Manual of Harmonic Analysis and Prediction of Tides" by Paul Schureman, 1971.
From archive at: https://archive.org/details/manualofharmonic00schu

Find a copy of; "Limitations of High Precision Tidal Prediction" by B. Ducarme, and any other papers from that authors.

Don't forget that the Earth has a solid tide. The reference mark on the rock will also rise and fall as you measure the height of the sea level tide.
Because of changing ionospheric conditions, GPS has too much vertical variation to establish an accurate bench mark reference level.
 
Baluncore, thank you kindly for your thorough, but not dissmissive replies. All technical forums need more of your ilk.

-Jeff Evarts
 

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