The Minimum Speed in the Universe: An Exploration of the Cosmic Limit

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Discussion Overview

The discussion revolves around the concept of minimum speed in the universe, exploring theoretical implications, relativistic perspectives, and potential quantum gravity considerations. Participants examine the nature of speed and velocity, particularly in the context of relativity and the invariance of the speed of light.

Discussion Character

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

Main Points Raised

  • Some participants assert that the minimum speed is 0 m/s, emphasizing that speed is relative and can be defined differently in various inertial reference frames.
  • Others propose that there might be a smallest measurable velocity based on quantum gravity arguments, suggesting a potential limit related to the cosmological constant and Planck length.
  • There is a discussion about the distinction between speed and velocity, with some arguing that while speed can be zero in a given frame, it does not imply absolute rest.
  • Participants debate the definition of the speed of light, with some suggesting it is a defined constant while others argue it is an observed invariant speed.
  • Concerns are raised about the implications of discussing absolute speed or rest, with some participants stating that such concepts cannot be meaningfully applied in the context of relativity.
  • One participant questions the necessity of synchronization in measuring speeds, suggesting that relative velocities can be assessed independently by a single observer.
  • Another participant introduces the idea that the normal concept of speed may not apply to the universe as a whole, proposing that discussions could focus on the speed of expansion or contraction instead.

Areas of Agreement / Disagreement

Participants generally agree that speed is relative and can be defined differently depending on the reference frame. However, there is no consensus on the existence of a minimum speed in the universe, with multiple competing views and unresolved questions regarding the implications of absolute versus relative speed.

Contextual Notes

Limitations include the dependence on definitions of speed and velocity, the unresolved nature of quantum gravity arguments, and the implications of discussing absolute rest or speeds in the framework of relativity.

  • #61
Rob Benham said:
Given that measuring the speed of light over short distances requires a very precise clock, is there any significant time taken for the photons to be 'processed'* by the mirror to send them on their return journey?

*I've just read a little on what takes place but it seemed even more complex than I remember. Nowhere did I find a typical time taken.
Nobody is going to try to measure the speed of individual photons. How would you know when the photon was emitted at the source? If you want to pursue this subject, I suggest you open a new thread in the quantum forum.
 
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  • #62
OK, the OP is banned and his/her question was fully and completely answered in post 2. Is there any point in continuing?
 
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