Elasticity of Spacetime: Does Spacetime Stiffen?

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    Elasticity Spacetime
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Discussion Overview

The discussion centers around the concept of elasticity in spacetime, exploring whether spacetime can be considered to have properties such as stiffness or elasticity. Participants examine this idea from various angles, including theoretical implications and the mathematical frameworks used to describe spacetime.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question whether spacetime can be described as having elasticity, arguing that it is merely a geometric framework rather than a physical entity that can be bent or stretched.
  • One participant suggests that spacetime exhibits stiffness at first derivatives and becomes stretchy at second derivatives, although this claim prompts requests for clarification.
  • Another participant mentions a speculative model treating spacetime as an elastic medium, noting that this approach is not necessary for understanding the standard model of spacetime in General Relativity.
  • There is uncertainty regarding the naming of the speculative model, with one participant stating they are unaware of any specific name for it.
  • One participant expresses skepticism, suggesting that the discussion may be more about playful numerical exploration rather than a serious theoretical framework.

Areas of Agreement / Disagreement

Participants express differing views on the nature of spacetime and its properties, with no consensus reached on whether it can be considered elastic or stiff. The discussion remains unresolved with multiple competing perspectives presented.

Contextual Notes

Participants highlight the complexity of discussing spacetime elasticity, indicating a dependence on mathematical definitions and frameworks, particularly the distinction between Euclidean and Riemann geometries. There is also mention of the speculative nature of some models, which may not align with established theories.

sqljunkey
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Does spacetime have elasticity ? I was reading this and they are talking about the stiffness of spacetime.
 
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sqljunkey said:
Does spacetime have elasticity ? I was reading this and they are talking about the stiffness of spacetime.
Spacetime is not a "thing" that can be bent or stretched, or have stiffness or elasticity, it is just geometry. We use the term "bent" regarding the path of objects through space-time but that is only by applying Euclidean Geometry, which actually does not apply. Objects, in the absence of other force, travel in straight lines in space-time, but these "straight lines" are more correctly called "geodesics" and are straight lines in Riemann Geometry (but bent in Euclidean Geometry) which is the correct math to describe space-time.

EDIT: I should also note to be completely correct that I have been told by people who understand this thing way better than I do that it is actually "pseudo" Riemann Geometry that describes space time.
 
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sqljunkey said:
Does spacetime have elasticity ? I was reading this and they are talking about the stiffness of spacetime.
Spacetime is stiff upon first derivatives then gets stretchy at 2nd derivatives.
 
dsaun777 said:
Spacetime is stiff upon first derivatives then gets stretchy at 2nd derivatives.

What do you mean by that?
 
sqljunkey said:
I was reading this and they are talking about the stiffness of spacetime.

What they are talking about is a speculative model in which what we call "spacetime" is treated as if it were an elastic medium in order to investigate the implications of such a model. It is not something that can really be discussed at the "B" level and it is certainly not something that needs to be considered at all in order to understand the standard model of spacetime in General Relativity.
 
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yeah I'm sorry it's confusing to me to figure out which discussion level to use here. Does this speculative model have a name?
 
sqljunkey said:
Does this speculative model have a name?

Not that I know of.
 
I think it's just Kirk playing with numbers.
 
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