What is the fabric of space made of

[Fra]

So for those of you who are claiming that empty space is "nothing" or just geometry, have some explaining?

I think I loosely addressed this questions in my posts in this thread, though not perhaps explicitly.

If we reduce space to geometry, we can ask then "what is geometry made of". As I tried to imply, IMHO this is a relation between the observer and the observed. And thus ultimately a relation between matter and it's environment. In particular in the abstraction of the observers information about it's enviroment, and the "local picture" of the state of the world, that's implied by a systems information abount the remainder of the universe. In this information geometry can be defined as properties of information. See http://en.wikipedia.org/wiki/Information_geometry.

I maintain my personal opinon that empty space makes as little sense as does matter without space, and as does observations without observers.

I think this ultimate meaning of this apparently circular argument is difficult to get a grip on. It has taken me som time to acquire an intuitive understanding of this. But now I think it has a deep satisfactory beauty. The concept goes hand in hand with an evolutionary view of relations. All relations evolve, without fixed points.

The problem with a lot of normal info.geometry is that it's using a background. Like a notion of a background probability or universal entropy. But this can I think be improved. I think it's still an open question. But to me the choice of direction is clear.

/Fredrik

 

[Dale]

If we reduce space to geometry, we can ask then "what is geometry made of". As I tried to imply, IMHO this is a relation between the observer and the observed. And thus ultimately a relation between matter and it's environment.

I think you are essentially stating Mach's principle which is broadly accepted. However, the question "what is geometry made of" is loaded since it implies the conclusion that geometry is made of something. That said, I agree completely that in physics geometry describes the relationship between physical things (I wouldn't limit it to observers and the observed). This is the sense in which spacetime was created at the big bang and the sense in which the universe expands.

 

[Fra]

I think you are essentially stating Mach's principle which is broadly accepted. However, the question "what is geometry made of" is loaded since it implies the conclusion that geometry is made of something. That said, I agree completely that in physics geometry describes the relationship between physical things (I wouldn't limit it to observers and the observed). This is the sense in which spacetime was created at the big bang and the sense in which the universe expands.

Yes, "what geometry is made of" might be a strange question, but as I interpret it, is what's the physical basis for geometry? I mean, I think my deviation from what almost all physicists would agre on is: Geometry is an mathematical abstraction. Alot of people are not disturbed by the fact that even the laws of physics, stated as mathematical laws are abstractions. Some have no problem to see these laws as independent of the physical world. I have a problem with this.

The physical basis I refer to, that solves this, is basically part of the observer. It means that there is not really any universal, observer-independnet laws, because even relations between objects, needs to be related to by other systems. Ie. you can only relate to a relation.

This is why I personally think the idea of perfect universal symmetry as a means to look for unification is not as good guide as it perhaps was 100 years ago. Because the notion of symmetry itself, is relative. In say GR, the observer invariants are assumed to be eternal laws of physics, but it doesn't handle the fact of information exchange and representation and the fact that the knowledge about these laws, are constrained to parts of the system.

I've posted about my opinions in many other threads, and this isn't the best exposition but as I see it, this takes machs principle to another level. Not only is physics about relations, the point is that there are also only relations to the relations! There is no fixed reference to even described a relation. This is the B/I problem, taken to more than just spacetime, it applies to all laws and statements.

The interesting question isn't if space is made of wood or wool, but what the physical representation of the information, implied in the abstractions used (ie geometry etc). Clearly this abstraction is encoded somewhere, at minimum in the scientists brain.

I am essentially critizising a realist view of physical law. Even if we think of laws as relations, the consistency of reasoning doesn't hold if we think of knowledge about this physical law as a non-relation.

/Fredrik

 

[Fra]

in physics geometry describes the relationship between physical things (I wouldn't limit it to observers and the observed).

Of course I agree with this as well. My choice of "observer" was meant not as a limit, on the contrary, do I see the analogy between observation / observer, and relations / matter in physical systems. A physical system, is well qualified as "an observer" in my abstraction. Could be an atom for example.

So when I said observation, I have in mind a "physical observation", ie basically a physical interaction. To me there is a difference in tone here, since I like the information picture better. Communication, observation and physical interactions are to me different words for the same thing.

/Fredrik

 

[stevebd1]

In theory, the energy that makes up both matter and space combines at Planck dimensions, creating a quantum 'foam' supported by either Loop Quantum Gravity or strings so if matter/space was to collapse to Planck dimensions, it would be a combination of both matter and space rather than just collapsed matter in space. I can't remember where I read this but it does imply that space has a constitution. I have heard that virtual particles, while virtual, do contribute some kind of residual effect or wave that possibly supports the existence of space (I suppose this is backed up to some extent by the Casimir effect).

 

[ThomasT]

Originally Posted by ThomasT
Nobody has a definitive answer for the question that's the title of this thread.

I do, and I already gave it:
Spacetime is just the geometry of physics.

I don't see spacetime in the title of this thread.

planck wants to know the physical makeup of the fundamental medium. Nobody knows -- and if the fundamental medium is structureless, then nobody ever will know. We're limited to conjecturing quantum foam(s) or strings, etc., which are at least one step removed from a fundamental medium that might be called space itself.
It seems that questions regarding the fabric of space will always have to do with some sort of activity as far as we can be concerned.

 

[Dale]

I don't see spacetime in the title of this thread.

This is a rather trivial objection to my point. Space is just any arbitrary spacelike hyperplane of spacetime, it is still just the geometry of physics. I simply use the word spacetime because it concisely implies that the geometry is not Euclidean.

The point remains that spacetime is nothing more than the geometry of physics and has only geometric properties such as distances and angles. This view is a core part of all mainstream physical theories including Newtonian physics, relativity, and QM, and is supported by several centuries of experimental evidence.

 

[Mk]

No, space did not exist before the big bang, yes, it was created, along with everything else.

You say that like you are so sure.

 

[tiny-tim]

You say that like you are so sure.

(that was seventy-six posts ago! )

Maybe he was there! ​

 

[ronjanec]

I believe space is a static singular distinct physical entity. The seamless physical material that makes up the fabric of space is not made up or composed of any particles or things or is like a elementary particle or fundamental particle in it's compostion.

Because of it's no particle or thing composition the space entity could also exist on the smallest level or say between the nucleus of the atom and it's electron(s), eliminating the illogical nothing existing here. The space entity is also any vacuum existing anywhere or is what is left after someone removes the air from something.

How large is the space entity? If you look at this from a strictly scientific viewpoint it must be infinite and have no end(s).

 

[martin1223]

Spacetime is just the geometry of physics.

You can describe a geometric shape and curve it mathematically but space-time actually curves; it certainly has the characteristics of a thing. Is the Universe a thing if it was empty? I guess I am asking are dimensions things? What happens to space-time near a black hole?

 

[martin1223]

Exactly. It wouldn't be surprising if space, time, and gravitons all came together to create the space we're discussing. I just need to know what that dough is made of. (Please don't reply sugar, flour, yeast, egg, etc..)

Why space-time is the dough, the basic thing in the universe curves and stretches out of existence into a black hole. Before the big bang, there was no-thing.

 

[jreelawg]

Nobody knows. Fabric of space time is a concept of general relativity, and doesn't really seek to answer that. If you notice the term space, which refers to measurements of distance and such, often called the metric, or the ruler. The concept is that distance and time are linked and both relative.

I think we will probably learn more about the nature and relationship of what it means for something to be something, and of what it means for something to have observable properties, and how it relates to what we cannot observe that fills the voids of what we can.

I just don't see why everything that exists ought to be observable? I am very open to the idea of things that may be closer to us and more fundamental than anything else which may be entirely unobservable. I suspect that if something is to be learned in this way, it will have to come from interpretation, and won't necessarily be verifiable mathematically.

I guess I'm talking about metaphysics which isn't looked upon highly of by many physicists and mathematical thinkers, and I think that this is due partially to lack of advancement in the subject. In the olden days, people tried to interpret the very limited knowledge they had and came up with various metaphysical theories. I have hopes that one day, after the LHC and other new age experimentation have been explored and as the pieces of knowledge begin to unfold, a modern interpretation of metaphysics will be the answer to the question, and will evolve over time getting clearer and clearer, until our understanding of the universe, space, time, and everything in between will be eventually be understandable by even the layman.

 

[tauon]

it's made of nothing at all.

 

[Sorry!]

it's made of nothing at all.

Oh really! What a fascinating remark, and where is your source for this cause I would love to read through it.

 

[tauon]

Oh really! What a fascinating remark, and where is your source for this cause I would love to read through it.

mathematics...

space is a mathematical framework of relations between objects, it is the distances between things and a web of geometric relations.
but mathematics is merely a concept, not something "physical".
ergo, space is merely a conceptual framework.

 

[Sorry!]

mathematics...

space is a mathematical framework of relations between objects, it is the distances between things and a web of geometric relations.
but mathematics is merely a concept, not something "physical".
ergo, space is merely a conceptual framework.

Oh, how interesting. Mathematics is your source for this. Well then, show me your mathematics to PROVE that space is nothing. Tut, tut now.

And yes it is going to have to PROVE that space is nothing because you've taken space out of the science realm where nothing is proven and brought it to the mathematical realm, where proofs exist.

 

[jreelawg]

mathematics...

space is a mathematical framework of relations between objects, it is the distances between things and a web of geometric relations.
but mathematics is merely a concept, not something "physical".
ergo, space is merely a conceptual framework.

Space is nothing but a concept, but what about the fabric of Space? That is an entirely different question then asking what space is. This is a question that is beyond mathematics. The answer to this is found through observation and interpretation, if possible at all. As it is, space is used as a tool to describe objects, how fast they are moving, how far apart they are, and how massive they are. People sometimes mistake the fact the relativity doesn't say anything about what the fabric of space time is, for a belief that nothing is there at all.

 

[jreelawg]

Imagine that there was a time not so long ago when man thought that the air was nothing. Even though we felt wind, and had to breath, nobody could explain what it was, and probably thought nobody ever could. I think there is a syndrome man gets when some sort of knowledge is out of his reach, we make something up, or deny the existence of, and close the case until a rebel proves us wrong. I think one day this will happen again.

 

[tauon]

Oh, how interesting. Mathematics is your source for this. Well then, show me your mathematics to PROVE that space is nothing. Tut, tut now.

And yes it is going to have to PROVE that space is nothing because you've taken space out of the science realm where nothing is proven and brought it to the mathematical realm, where proofs exist.

Oh, what a fascinating personality you have.
I already made my point, if you are unable to comprehend it that's your problem, especially since I feel like I'm talking to a bratty little kid who just lost his candy and now is pissed at everyone, but fine:

When I said that space is nothing I meant it in the sense that space is not a substance, that it is not something physical - physical like elementary particles are discrete physical "objects" (as I clearly pointed out in my second post). My reasoning for it was self-evident and simple: we never observe space outside of a mere relational construct between objects. And that relational construct we use is mathematics (especially in a scientific context, and not a colloquial one) - space is in a way, just mathematics.

But mathematics is not a physical substance - it is merely a concept, a collection of ideas (of course for the sake of brevity, I am oversimplifying the description of mathematics).

 

[Sorry!]

Imagine that there was a time not so long ago when man thought that the air was nothing. Even though we felt wind, and had to breath, nobody could explain what it was, and probably thought nobody ever could. I think there is a syndrome man gets when some sort of knowledge is out of his reach, we make something up, or deny the existence of, and close the case until a rebel proves us wrong. I think one day this will happen again.

Some guy in the early 1900s wrote papers about some sort of 'sea of negative energy' Dirac or something. Not accepted mainstream in physics though.

Space to me is just a concept therefore the question what is space made of, or even the fabric of space. Is begging the question. So the answer isn't 'nothing', at least I don't think... it's that such questions don't make sense.

It's like asking what is outside the universe. Some scientist might say 'nothing' but that is because it is beyond the scope of attainable knowledge so it is a pointless question.

 

[jreelawg]

It's like asking what is outside the universe. Some scientist might say 'nothing' but that is because it is beyond the scope of attainable knowledge so it is a pointless question.

Exactly, but there is a history of underestimating our scope.

I also don't like the term outside the universe. There is a limit to how far we can see, but that doesn't make what we can't see not part of the universe.

 

[tauon]

@jreelawg:

Occam's razor.
All physical facts can be described in terms of properties of objects and the relations between them.
Why should we suddenly introduce another object (a physical spacetime) when it is not necessary?

 

[Sorry!]

Exactly, but there is a history of underestimating our scope.

I also don't like the term outside the universe. There is a limit to how far we can see, but that doesn't make what we can't see not part of the universe.

Sure we may be underestimating our scope but until the time that we realize the potential we have been failing to see questions as such remain pointless. Space by definition is merely a concept and answering what it is made of makes no-sense.

 

[jreelawg]

@jreelawg:

Occam's razor.

That's an easy way out isn't it. So a fabric of space time doesn't exist because it isn't necessary to make calculations about objects. Is that what your getting at. What if you want to know if space time is something, and what it is, rather than how an object is behaving relative to another.

 

[jreelawg]

@jreelawg:

Occam's razor.
All physical facts can be described in terms of properties of objects and the relations between them.
Why should we suddenly introduce another object (a physical spacetime) when it is not necessary?

As I stated before, whatever the fabric of space time is, it may have components which exist and are by nature unobservable directly by physical instruments. Sometimes the words don't exist to try to explain such things. I don't know if something has to be physical as we know it to exist. As you state, physics isn't very concerned with things like this, and as I stated, it will be interpretive metaphysics of the future that best explain these "pointless" questions.

I am not suggesting changing the theory of Relativity, or anything, just expressing my belief that one day a more sensical understanding will be possible.

 

[nevagil]

My first thought is that it's made of the same stuff we are. Processed more or less. It makes me wonder how much space is in me in that particular form.
It feels good if I wave my hand thru it.


Meditate, don't medicate.

 

[Dale]

You can describe a geometric shape and curve it mathematically but space-time actually curves; it certainly has the characteristics of a thing. ... I guess I am asking are dimensions things?

This depends entirely on the definition of the word "thing". It is a semantic argument that is rather uninteresting.

What happens to space-time near a black hole?

It curves a lot.

 

[petm1]

I think of light as being the fabric of space, with the photon as the thread and matter the ball of yarn. That would make space the loom, time the the room, and you can believe in any weaver that you want. Sorry if this seems to simple but it made me smile when I thought of it.

I wrote this back in 08 in another thread but I still like it.

 

[tauon]

As I stated before, whatever the fabric of space time is, it may have components which exist and are by nature unobservable directly by physical instruments. Sometimes the words don't exist to try to explain such things. I don't know if something has to be physical as we know it to exist. As you state, physics isn't very concerned with things like this, and as I stated, it will be interpretive metaphysics of the future that best explain these "pointless" questions.

I am not suggesting changing the theory of Relativity, or anything, just expressing my belief that one day a more sensical understanding will be possible.

if as you say, the supposed "fabric" of spacetime is experimentally unobservable, than it is not falsifiable, hence not something science can address.
and if that's the case than pretty much any view stands, we could even say the fabric of spacetime is made of cosmic butterflies, or godly chocolate. evidently, I'm not a "fan" of "metaphysics".

also, I would like to clarify that I did not state that spacetime does not exist, but that it isn't a physical "substance", that it's merely a conceptual framework: it is [mathematical] relations between objects and events.

 

[WaveJumper]

also, I would like to clarify that I did not state that spacetime does not exist, but that it isn't a physical "substance", that it's merely a conceptual framework: it is [mathematical] relations between objects and events.

"Physical substance" is a form of condensed energy, so yes, space is certainly not condensed energy.

 

[petm1]

No not condensed energy, but space is full of stretched energy, photons in transit between events.

 

[Buckethead]

What a great thread!

I am satisfied that the question of "what is the fabric of space made of" (or more reasonably "what is space") was answered in this thread.

My take on it reflects several other posts in that I think that "space" truly does not exist. More clearly in my opinion I think "space" is our perception of what happens when matter and energy exist. This is also another way of saying that not only does space not have a material existence, but it does not even reflect any kind of geometry. This is not to say that an apparant geometry in an apparant space does not exist, but it may be that it is only the relationships between matter/energy/other that we ultimately observe as being (for example) a particle moving along a geodesic in space and is not in fact a particle moving along a geodesic in space.

It makes sense to me that if you take all matter, energy, and anything else in reality out of space (if it existed), you would be left scratching your head what could possilby be left. And even though you can assign mathematical properties to "space" you cannot say that properties themselves are anything more than an illusion created by the relationships between objects in reality that do truly exist to our senses/instruments.

Take the property of distance for example. This seems like a property of space, but space is not made up of distance, there is only distance between objects. And what is that distance? It is defined by how much time it takes a photon (for example) to move from one of those objects to the other. Increase the distance between them (if you could, which you couldn't if space didn't exist), and increase the value of c proportionally and to an outside observer it would appear as if the space between them has remained the same, when instead we have increased the so called space between the objects. Change the speed of light enough and you can make a chunk of space infinitely big or infinitely small without changing the real size of the space between those objects. You may object by saying you can't change the speed of light, but that only tells me that the speed of light is the relationship between two objects and is not related to the so called "distance" between them. This might be another way of saying that two objects might be superimposed over one another (no space between them) and yet there is a finite time that it takes for light to move from one of the objects to the other. This finite time is seen as a "distance" between the objects due to the set value of c. (yes, I know that's a bit strange, but so is matter/energy equivalence or wave/particle duality!)

So yes, it seems to me space does not exist in any way, shape, or form, only matter/energy/other exist.

Again, great thread and great answers.

 

[jabernal]

Recently, dark matter and dark energy were discovered. 97% of all the universe is made of this invisible stuff. Perhaps this is the fabric of space. After all, for objects to create a warp in space, they must be pressing against something.

 

[GeorgCantor]

Recently, dark matter and dark energy were discovered. 97% of all the universe is made of this invisible stuff. Perhaps this is the fabric of space. After all, for objects to create a warp in space, they must be pressing against something.

No, they are not the ultimate unchanging, non-relative 'substance' of the universe. That still hypothetical 'substance' has yet to be found, and that IMO is the single most interesting question a human being can ask, while he/she is alive.

"What is the fabric of space made of?" is actually the same as "What is the ultimate unchanging, non-relative and non-contextual 'substance' of the universe"?