# Elasticity of Spacetime: Does Spacetime Stiffen?

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• sqljunkey
In summary, the article discusses a speculative model in which 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.
sqljunkey
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.

vanhees71, jedishrfu and WWGD
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.

phinds and vanhees71
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.

vanhees71 and phinds

## 1. What is the concept of elasticity in relation to spacetime?

The concept of elasticity in relation to spacetime refers to the ability of spacetime to bend and stretch in response to the presence of matter and energy. This is described by Einstein's theory of general relativity, which states that massive objects cause spacetime to curve, creating the force of gravity.

## 2. How does the stiffness of spacetime affect the movement of objects?

The stiffness of spacetime, or its resistance to bending, affects the movement of objects by determining the path they take in the presence of gravitational forces. Objects will follow the curvature of spacetime, which can be influenced by the stiffness of the spacetime itself.

## 3. Can the stiffness of spacetime change?

According to general relativity, the stiffness of spacetime is a constant and cannot be changed. However, there are theories that suggest that the stiffness of spacetime may vary in different regions of the universe or under extreme conditions, such as near black holes.

## 4. How is the stiffness of spacetime measured?

The stiffness of spacetime is measured using mathematical equations and observations of the effects of gravity on objects. General relativity provides a framework for calculating the curvature of spacetime and determining its stiffness.

## 5. What are the implications of a change in the stiffness of spacetime?

If the stiffness of spacetime were to change, it could have significant implications for our understanding of gravity and the behavior of objects in the universe. It could also potentially impact our ability to accurately predict and model the movements of celestial bodies.

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