What is Space?

I don't have a deep understanding of the theory, but in my (limited) understanding, space is not nothingness. It is only a region which does not contain ordinary matter. Of course there were historical debates about another topic, regarding light, radio and other electromagnetic waves. Like familiar waves on water or soundwaves in air, it was suggested that space was filled with an invisible aether through which waves could propagate. But that idea was discarded when experiments demonstrated it could not be so. Nevertheless, the best way I can describe it to myself is that space is the region where the mathematical descriptions of physics apply. I think it is possible that there could be some region where no such rules applied, a real 'nothingness'. But that would be outside our universe.

As I said I don't have a deep knowledge, but as physicists or cosmologists consider the so-called big bang, all the rules of physics break down, mathematics becomes filled with infinities and zeros where equations cannot work. Here I suppose I'm talking about time rather than space, but the two seem to be part of the same thing.

Edit: The relevance of the idea of the Big Bang is important with regard to space. As I understand it, it isn't the case that there was all this vast 'empty' space as we understand the term, just sitting there waiting to be filled with matter and energy. Rather, there was no space, it too began with the big bang. Matter didn't expand to fill space. Space and matter expanded together. But I'm not a proper physicist, there are more precise descriptions than my everyday colloquial words.

I don't have a deep understanding of the theory, but in my (limited) understanding, space is not nothingness. It is only a region which does not contain ordinary matter. Of course there were historical debates about another topic, regarding light, radio and other electromagnetic waves. Like familiar waves on water or soundwaves in air, it was suggested that space was filled with an invisible aether through which waves could propagate. But that idea was discarded when experiments demonstrated it could not be so. Nevertheless, the best way I can describe it to myself is that space is the region where the mathematical descriptions of physics apply. I think it is possible that there could be some region where no such rules applied, a real 'nothingness'. But that would be outside our universe.

As I said I don't have a deep knowledge, but as physicists or cosmologists consider the so-called big bang, all the rules of physics break down, mathematics becomes filled with infinities and zeros where equations cannot work. Here I suppose I'm talking about time rather than space, but the two seem to be part of the same thing.

Edit: The relevance of the idea of the Big Bang is important with regard to space. As I understand it, it isn't the case that there was all this vast 'empty' space as we understand the term, just sitting there waiting to be filled with matter and energy. Rather, there was no space, it too began with the big bang. Matter didn't expand to fill space. Space and matter expanded together. But I'm not a proper physicist, there are more precise descriptions than my everyday colloquial words.

Indeed and I agree with all of what you say here. Before asking myself the question that I have asked in this thread, I did previously ponder on discussions about the Big Bang. I think that in some respects, it boils down to the inability of the human mind to conceive of certain concepts. One example is the 3D curve (as in the curvature of space) although when I say that to people they usually come back with "of course I can imagine a 3D curve - what about a banana?". But a banana is not a 3D curve because what we see is a curved surface which is 2D.

So, coming back to the Big Bang, the thing we can't intuitively grasp is that space does not expand into something (or "nothingness") - there is no "outside" of space into which it expands. There is no infinite space into which our universe expands. I don't know about anyone else but just thinking about this boggles my mind.
The only encouragement I get from these mental forays into the unknowable is that it does seem that whenever scientific theory encounters these boundaries, materialism seems to fail in its explanatory power. This is true for quantum mechanics (e.g. entanglement) or particle physics where, the deeper we look, the more it becomes obvious that matter itself is not understood, as stated in the conclusion of this article:

https://www.quantamagazine.org/what-is-a...-20201112/

“What are the fundamental building blocks of the universe on its most fundamental scales?” — a more sophisticated phrasing of my question, “What is a particle?”

In the meantime, Engelhardt said, “‘We don’t know’ is the short answer.”

So, coming back to the Big Bang, the thing we can't intuitively grasp is that space does not expand into something (or "nothingness") - there is no "outside" of space into which it expands. There is no infinite space into which our universe expands. I don't know about anyone else but just thinking about this boggles my mind.

Well as you know, I'm pretty sceptical about science full stop. However, I suppose the standard way to interpret that statement would be to imagine that we lived on the surface of a balloon and were unaware of the third dimension. Then if the balloon was inflated more, there would be more (two dimensional) space for everything.

Now you have to add an extra dimension so you start with a three-dimensional surface!!!

Notice also that an inflated balloon has no edge (if you ignore the place where you blow), so if you are an insect on the surface, travelling far enough brings you back to where you started from. That idea also scales to three dimensions.

David

I see explanations of 3D space using 2D visualisations all the time. That rubber sheet analogy for Einstein's gravity/curved space theory is just one such (see attached video). I've also seen the expanding balloon metaphor. All this says to me is that we need these 2D representations because we can't acually conceive of the 3D reality. Perhaps that is a human "designed limitation": perhaps being able to see multi-dimentional realities would open the doors of perception to other worlds that we only suspect are there? Perhaps meditative insights or psychedelic drugs might prise open the doors of perception a little? Perhaps there a clues to this right under our noses but we are "encouraged" to ignore them by those invested in their own worldview?

https://youtu.be/wrwgIjBUYVc

I see explanations of 3D space using 2D visualisations all the time. That rubber sheet analogy for Einstein's gravity/curved space theory is just one such (see attached video). I've also seen the expanding balloon metaphor. All this says to me is that we need these 2D representations because we can't acually conceive of the 3D reality. Perhaps that is a human "designed limitation": perhaps being able to see multi-dimentional realities would open the doors of perception to other worlds that we only suspect are there? Perhaps meditative insights or psychedelic drugs might prise open the doors of perception a little? Perhaps there a clues to this right under our noses but we are "encouraged" to ignore them by those invested in their own worldview?

Alexander Unzicker claims that in 1911 Einstein came up with the idea that the speed of light is slower in a gravitational field. He further claims that at the time he made a mistake of a factor of two when calculating the bending of starlight round the sun. With that correction made, there would be no need for the (to me) horrible idea that space-time itself is warped - i.e. General Relativity.

I can't possibly assess who is right, but I think a big part of the problem is that once a theory like GR becomes established in the scientific community, it is nearly impossible to dislodge it because people have learned the math and become attached to it. This is a flaw in the sociology of science really.

Alexander Unzicker claims that in 1911 Einstein came up with the idea that the speed of light is slower in a gravitational field. He further claims that at the time he made a mistake of a factor of two when calculating the bending of starlight round the sun. With that correction made, there would be no need for the (to me) horrible idea that space-time itself is warped - i.e. General Relativity.

I can't possibly assess who is right, but I think a big part of the problem is that once a theory like GR becomes established in the scientific community, it is nearly impossible to dislodge it because people have learned the math and become attached to it. This is a flaw in the sociology of science really.

This is just a totally flawed argument/misunderstanding. For more than 50 years it has been and is a very active research field within physics/cosmology to come up with an alternative theory for gravity that solves some of the shortcomings with GR. Multiple proposals exists which all have their own flaws. Some of these proposals differs fundmentally from GR. People are working on this every day.

I see explanations of 3D space using 2D visualisations all the time. That rubber sheet analogy for Einstein's gravity/curved space theory is just one such (see attached video). I've also seen the expanding balloon metaphor. All this says to me is that we need these 2D representations because we can't acually conceive of the 3D reality. Perhaps that is a human "designed limitation": perhaps being able to see multi-dimentional realities would open the doors of perception to other worlds that we only suspect are there? Perhaps meditative insights or psychedelic drugs might prise open the doors of perception a little? Perhaps there a clues to this right under our noses but we are "encouraged" to ignore them by those invested in their own worldview?

https://youtu.be/wrwgIjBUYVc

Thanks for this, great video...Though it leaves me with more questions. He says we shouldn't explain Gravity in terms of Gravity which is what the image of the Earth creating a depression in space-time fabric does. I agree this is erroneous, but then in his explanation the apple moves through the curvature of the supposed 4th axis of time....

Isn't that sort of like explaining Time using Time?

This is just a totally flawed argument/misunderstanding. For more than 50 years it has been and is a very active research field within physics/cosmology to come up with an alternative theory for gravity that solves some of the shortcomings with GR. Multiple proposals exists which all have their own flaws. Some of these proposals differs fundmentally from GR. People are working on this every day.

Can you point out what exactly the flaw is?

Can you point out what exactly the flaw is?

I think a big part of the problem is that once a theory like GR becomes established in the scientific community, it is nearly impossible to dislodge it because people have learned the math and become attached to it. This is a flaw in the sociology of science really.

You can argue that science is firmly grounded in physicalism. But that new ideas within this paradigm isn’t regulary proposed and tested is wrong.

You can argue that science is firmly grounded in physicalism. But that new ideas within this paradigm isn’t regulary proposed and tested is wrong.

I am not arguing this from the point of view of extended reality (though that is possibly not irrelevant). Neither is Alexander Unzicker, he is saying that the evidence for GR can be explained using a much simpler mathematical model than GR.

It is well known that GR and QM are incompatible in a fundamental way - basically one or other of them is wrong. I'd say QM s far better tested because the apparatus is entirely under our control. The sociological problem with that is that the 'experts' have spent all their adult life immersed in tensor calculus, 10-dimensional spaces, etc. - dropping GR would involve accepting that they have wasted most of their intellectual life.

String theory was supposed to resolve that incompatibility, yet it would seem people are starting to give up on the idea.

I don't like the idea that the coordinate system is somehow part of the physical action, rather than being what it really is - a mathematical abstraction which facilitates calculation. It is almost like claiming that the choice of character set (Greek vs Arabic) has some fundamental significance - it just feels wrong to me. That form of tensor calculus no doubt has its place when considering deformable materials - such as rubber - because then you can choose to fix your coordinate system to the rubber - but that is more of a mathematical convenience, like using sqrt(-1) in electrical formulae.

Alexander Unzicker expresses his point of view a little aggressively at times, but he is well worth reading. I don't know if you work(ed) in areas that used GR, and I know we all get attached to scientific ideas - he will probably challenge your ideas in ways you will find uncomfortable.