The speed of gravitational field propagation

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Discussion Overview

The discussion centers on the speed of gravitational field propagation, particularly within the frameworks of special and general relativity. Participants explore whether gravity must propagate at the speed of light and consider alternative speeds, as well as implications for orbital stability in celestial mechanics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions if it is theoretically valid for gravitational fields to propagate at speeds less than the speed of light, such as 0.9c or 0.99c.
  • Another participant expresses confusion about how planets maintain stable orbits given the time delay in gravitational influence from the sun.
  • Some participants reference an article discussing how certain effects of gravity may compensate for propagation delays, but express skepticism about the explanations provided.
  • A participant critiques the argument that gravitational equations inherently cancel out retardation effects, suggesting it lacks depth and may be oversimplified.
  • There is mention of the quadrupole dependence of gravity and how it relates to gravitational radiation, with some participants seeking clarification on the technical aspects of these concepts.
  • Concerns are raised about the implications of gravitational propagation speed on orbital stability, with references to the non-centrality of forces in general relativity.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the speed of gravitational propagation or the implications for gravitational theory. Multiple competing views and uncertainties remain regarding the necessity of gravity propagating at the speed of light and the effects of propagation delay on orbital stability.

Contextual Notes

Some participants note the limitations of existing explanations, particularly regarding the mathematical underpinnings of gravitational effects and the assumptions made in various theories. There is also a recognition that the discussion involves complex technical details that may not be fully addressed.

  • #61
Things to do for today:

1. switch on GPS, see if it works.

2. Look at the picture below, and describe in terms of mass and force what is happening.
 

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  • #62
Locked for moderation.
 

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