Sunday 1 October 2017

cosmology - Is space "real", or is it some sort of accepted postulate?


What is space?


It seems to be everywhere in the equations of physics, as some sort of postulate or hidden hypothesis. We also have a direct experience of it, but is it "real"? The fact that we experience it doesn't mean that it exists by itself. For example, what we are experiencing as heat or cold is just molecules that are vibrating at different speeds. Hence our sense of temperature is just an emerging effect that can be explained in base of more fundamental phenomena, to make my point.


Is it the same for space? Can physics explain space in a more fundamental way, or is it some sort of accepted postulate? And if physics can explain it, then what is space?



On the same line, what is a vacuum (absence of matter)? Is there a vacuum everywhere in space? And what does it mean or imply? Or, is it that space is dragged in by matter? Or does space manifests itself only in presence of matter? In the latter case, what is the relationship between space and matter that shows that?


Voila! Apologies for the naive questions, but every time I think about space I'm stuck. I don't get it. Yes, I experience it as everybody else does, but I don't understand how it fits in the big picture, it's almost like we just have to accept it as it is. Maybe it's the case, but I guess you probably have a better insight than me on the subject.


Also, I thought this could add water to the mill. It's a link to one of Sean Carroll's blog posts on the question of whether or not space is fundamental.




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