Discussion Overview
The discussion revolves around the propagation speeds of fundamental forces such as gravity, magnetism, and the strong and weak nuclear forces, particularly in relation to the speed of light. Participants explore whether these forces act instantaneously or at speeds comparable to or slower than light, and the potential influence of the medium through which they act.
Discussion Character
- Debate/contested
- Technical explanation
- Exploratory
Main Points Raised
- Some participants assert that all fundamental forces are mediated by bosons, with gravity and electromagnetism described by massless bosons that propagate at the speed of light, while the weak force is mediated by massive bosons, suggesting a slower speed.
- There is a question regarding the masslessness of gluons and what that implies, with some uncertainty expressed about the definition of "massless."
- One participant requests experimental evidence to support claims that forces travel at the speed of light, questioning the relevance of the medium in this context.
- Another participant references a paper suggesting that gravity may propagate faster than light, citing the Poynting-Robertson effect as a basis for this claim, but acknowledges a lack of consensus on the validity of this paper.
- Concerns are raised about the credibility of the referenced paper due to its absence from peer-reviewed journals, with a participant emphasizing the importance of peer review in establishing scientific credibility.
- Some participants argue that all known forces and particles travel at or below the speed of light, while introducing the concept of tachyons, which are theorized to travel faster than light but have not been observed.
- Discussion includes a historical reference to an experiment by Fomalont and Kopeikin that purportedly measured the speed of gravity, with conflicting interpretations from other physicists regarding its validity.
- One participant discusses the implications of Newtonian gravity, suggesting that if gravity had a finite speed, it would lead to instability in planetary orbits, thus raising questions about the accuracy of Newtonian theory compared to general relativity.
Areas of Agreement / Disagreement
Participants express multiple competing views regarding the propagation speeds of forces, with no consensus reached on the speed of gravity or the validity of the referenced paper. The discussion remains unresolved with differing interpretations of experimental evidence and theoretical implications.
Contextual Notes
Some participants note that the speed of gravity has not been conclusively measured, and the discussion includes references to ongoing debates in the scientific community regarding the implications of general relativity and alternative theories.