Does Acceleration Affect Planck Lengths in General Relativity?

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Discussion Overview

The discussion revolves around the relationship between acceleration, time dilation, distance contraction, and the concept of Planck lengths within the framework of General Relativity (GR). Participants explore whether the Planck length is the shortest possible distance and how it may be affected by acceleration.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant asserts that as an object accelerates, time dilates and distances contract, questioning whether the number of Planck lengths decreases or if a Planck length itself gets shorter.
  • Another participant challenges the notion that the Planck length is the shortest possible distance in GR, stating that this idea stems from speculations about quantum gravity.
  • A further contribution emphasizes that an object that is one Planck length long in its rest frame will appear shorter than one Planck length in a moving frame.
  • Some participants reference an Insights article to clarify misconceptions about the Planck length and its implications in GR.

Areas of Agreement / Disagreement

Participants express disagreement regarding the status of the Planck length in GR, with some asserting it is not the shortest possible distance, while others maintain a belief in its significance. The discussion remains unresolved regarding the implications of acceleration on Planck lengths.

Contextual Notes

There are limitations in the discussion regarding the assumptions about the nature of distances in GR and the dependence on interpretations of quantum gravity. The mathematical implications of these claims are not fully explored.

BenAS
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Relativity say as an an object accelerates, time dilates and distances contract.

It is my understanding that the shortest distance possible is a Planck length, so as distance contracts, does the number of Planck lengths decrease, or does a Planck length get shorter? It would seem the former, but I don't know. I've got only a pop sci education

Is there a simple answer?
 
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BenAS said:
It is my understanding that the shortest distance possible is a Planck length

Not in GR. In GR there is no shortest possible distance. The idea that the Planck length is the shortest possible distance comes from speculations about quantum gravity.

BenAS said:
does a Planck length get shorter?

In GR, an object that is one Planck length long in its rest frame will appear shorter than one Planck length in a frame in which it is moving.
 
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