Does space move? What is space?

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The discussion centers on the nature of space and whether it can be said to move or expand. It highlights that while space-time is a framework for events, its properties like bending and expanding are contentious topics. Observations indicate that objects in the universe are moving apart, but this cannot be accurately described by simply stating that space itself is stationary. The concept of "metric expansion" is referenced as a key aspect of understanding how distances between objects increase. Ultimately, there is no model that can explain observed redshifts without considering the expansion of space itself.
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Does space move? What is space?
 
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Whether or not it is appropriate to say that space "bends / expands / curves" and so forth is a somewhat contentious issue. Basically, the math says that space-time is a framework in which things happen and does not itself matter. It "bends" in that geodesics near large bodies are not straight in the Euclidian sense. It "expands" in the sense that things get farther apart. Google "metric expansion" for further discussion.
 
phinds said:
It "expands" in the sense that things get farther apart.
Can't we just say that the objects are moving away from each other, through space, and the space itself is not moving?
 
k9b4 said:
Can't we just say that the objects are moving away from each other, through space, and the space itself is not moving?
For objects far away, this is not consistent with observations.
 
mfb said:
For objects far away, this is not consistent with observations.
But hang on, what do you mean it's not consistent with observations? How can you observe space moving? You can only observe relative motion, as dalespam pointed out in my other thread in this subforum.
 
k9b4 said:
But hang on, what do you mean it's not consistent with observations?
In the same way the hypothesis "there is no sun" is not consistent, just with more math involved.
How can you observe space moving? You can only observe relative motion, as dalespam pointed out in my other thread in this subforum.
Right, but there is no model that can reproduce the observed redshifts with objects moving in space.
 

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