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Absolutely cool thanks! Just a question, do you assume that the 'lab' at x=0 has negligible mass, or does it not feature in the final analysis?
Cosmic Tidal Force: Measuring CTF With Strain Gauge
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Discussion Overview
The discussion revolves around the measurement of the cosmological tidal force (CTF) using a strain gauge in a proposed experimental setup. Participants explore the implications of cosmic expansion on the tension in cables attached to masses at cosmological distances, considering both theoretical calculations and practical challenges in measurement.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
- Mathematical reasoning
Main Points Raised
- One participant proposes a setup to measure CTF by attaching cables to two identical masses at distance D/2, suggesting that the cosmological stress on the cables can be quantified using a strain gauge.
- Another participant raises concerns about the gravitational force between the two masses potentially affecting the tension in the cables.
- A participant emphasizes that the setup's validity hinges on the assumption that the cosmological constant applies at small scales, despite the general FLRW metric being an average over larger scales.
- There is a discussion about whether the strain in the cable represents a non-negligible stress energy within the experimental setup, with differing views on the significance of this strain relative to the energy density of dark energy.
- Some participants note that the weak field approximation used in the calculations should hold for large distances and masses, while others question the implications of strain and energy density in the context of the experiment.
- A thought experiment is introduced involving a light, long retractable measure to illustrate potential challenges in measuring distances as they increase due to cosmic expansion.
Areas of Agreement / Disagreement
Participants express differing views on the implications of gravitational forces, the applicability of the cosmological constant at small scales, and the significance of strain in the cables. The discussion remains unresolved, with multiple competing perspectives on the setup and its theoretical foundations.
Contextual Notes
Participants acknowledge limitations in their assumptions, particularly regarding the scale of the experiment and the conditions under which the weak field approximation is valid. There are also concerns about the neglect of certain factors, such as the mass of the cable and the nature of the vacuum in the experimental setup.
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