What is the fabric of space made of

[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"?

 

[nismaratwork]

What is spacetime made of? Math, because it's a model. If the real question here is "what is reality anyway" then the only real answer is, "who the @!&* knows?!".

 

[petm1]

How about change.

 

[GeorgCantor]

How about change.

Change of what and to what? Change of 'observations'?

 

[imiyakawa]

if as you say, the supposed "fabric" of spacetime is experimentally unobservable ...
it is [mathematical] relations between objects and events.

I'm butting in late, but has Newton's bucket experiment been discussed?

 

[petm1]

Change of what and to what? Change of 'observations'?

Everywhen and everywhere is constantly changing, from the outward motion I feel to the inward motion I see, it is the change that I sense as time. The little twist we use to view the results of big bang today changes the motion of the photons from a motion outside of matter back into a motion within matter, the observer. This dilating afterimage of our present from a point within the space of each observers eyes is the the change I see.

 

[brainstorm]

If the big bang was indeed the beginning of an expansion from a single point, then I think it could be said that spacetime is a product of expansionary energy. More specifically, if materialization is one expression of energy, and gravitation is a function of materialization insofar is mass is imparted; then kinetic energy of motion is what counteracts the gravitational attraction that tends toward reducing spacetime to non-existence.

I don't think that spacetime would exist if no energy would be materialized into matter with mass. I believe there has to be some tension between mass/gravitation and momentum for there to exist the relative separation between particles/objects (space) and between events (time). Likewise, if there was only a single source of light-emission with mass in the universe, I don't see why spacetime wouldn't simply curve back in on itself such that the light/energy would return to its gravitational source.

So, it would seem that for spacetime (fabric) to exist, there has to be 1) the construction of matter with mass/gravity and 2) the fragmentation/separation of that mass into multiple nodes with kinetic energy (momentum) sufficient to prevent them from collapsing into each other due to their gravitational attraction.

Once mass is established and energetic resistance of that mass to gravitational convergence, I believe spacetime (fabric) has been established. At that point, it is a question of further fragmentation and scaling between various sized pieces of matter, which can traverse the interacting gravitational fields of the more massive bodies. Without multiple massive bodies to form gravitational "poles," smaller particles would create their own spacetime by interacting energetically, but they would have no larger arena to break away from each other, except to the extent they would fragment into multiple large clouds with gravitational centers in orbit with each other.

 

[GeorgCantor]

More specifically, if materialization is one expression of energy, and gravitation is a function of materialization insofar is mass is imparted; then kinetic energy of motion is what counteracts the gravitational attraction that tends toward reducing spacetime to non-existence.

Kinetic energy of motion cannot exlain the ever increasing rate of expansion of the universe and Dark Energy is pretty much the new "Standard Model" these days(a sort of ultimate free lunch). It's a baffling example of nothing becoming a something. It's theorized that vacuum fluctuations should account for this force, but this will hardly be accepted as a rigorous statement as perpetual motion machines are tossed out without an examination.

 

[imiyakawa]

but this will hardly be accepted as a rigorous statement as perpetual motion machines are tossed out without an examination.

Virtual particles do not violate conservation, whilst perpetual motion machines do.

 

[GeorgCantor]

Virtual particles do not violate conservation, whilst perpetual motion machines do.

I was speaking of virtual particles causing the acceleration of the expansion of the universe, not merely going in and out of existence with observationally negligible effects.

 

[brainstorm]

Kinetic energy of motion cannot exlain the ever increasing rate of expansion of the universe and Dark Energy is pretty much the new "Standard Model" these days(a sort of ultimate free lunch). It's a baffling example of nothing becoming a something. It's theorized that vacuum fluctuations should account for this force, but this will hardly be accepted as a rigorous statement as perpetual motion machines are tossed out without an examination.

I was just illustrating a potential general relationship between radiation, matter, gravitation, and kinetic energy of material motion. If dark matter actually exists, I'm assuming it is some form of matter that exerts gravitational force without re-emitting energy at all somehow. Vacuum fluctuations would be caused by relative distribution of matter whose disequilibrium must be the product of gravity and patterns of kinetic energy transfers among particles within gravitational topography, right. So both explanations are still functions of interaction between gravitation/mass and repellant energy, no?

My big point was that there might be something inherent the the fact that matter is made of energy that causes energy to drive particles and objects away from each other when they collide. In other words, I suspect that the quality of matter to resist interpenetration in terms of particle rigidity is due to the ability of energy to repel other energy. Actually, I should google whether light can deflect other light because I am just thinking of electrostatic and magnetic repulsion.

Still, my hunch is that the attractive, convergent force of gravity is related to energy circulating in a closed-loop while repellant energy is related to open-loop energy trajectories. Thus, I think that black holes' ability to devour all energy is the end of one end of an energy-continuum where all linear expressions of energy bend in on themselves and at the other end of the continuum would be a star-system that was somehow able to completely convert all its matter into radiant energy.

I know this all sounds speculative and naively grand, but I'm not trying to push any new theories - just expressing a hunch about how gravitation and linear energy flows could be naturally counter-forces of each other as a result of the very mechanics of energy-looping.

 

[nismaratwork]

I was speaking of virtual particles causing the acceleration of the expansion of the universe, not merely going in and out of existence with observationally negligible effects.

The universe as a whole does not necessarily have to conserve energy; consider Dark Energy, and the redshifting of photons with spatial expansion. Interestingly, those "virtual particles" don't account for enough energy to balance the possible loss due to expansion. We're talking about a scale that is not open to this kind of analysis.

 

[brainstorm]

The universe as a whole does not necessarily have to conserve energy; consider Dark Energy, and the redshifting of photons with spatial expansion. Interestingly, those "virtual particles" don't account for enough energy to balance the possible loss due to expansion. We're talking about a scale that is not open to this kind of analysis.

You can analyze a model on whatever scale based on the assumption that all relevant parameters are known. If that assumption proves false, and it turns out that there are other influential parameters that you didn't take into account in your model, the model becomes that much less useful, but you can still attempt modeling and extrapolation from the model - it's not impossible.

What I would like to know is do you recognize space as being limited to gravitational topography, in the sense of Einsteinian curved spacetime, or do you presume space to exist independently of matter and its gravity? My assumption is that mass/gravity determines the curvature of space, and therefore it is never possible for EM radiation to escape matter indefinitely. Do you agree or do you think light can proceed infinitely away from any and all matter?

If matter is being converted into energy by stars everywhere, then presumably the mass of the universe is decreasing, unless there is some other process by which energy is getting converted into matter. I have personal hunches about how this could be happening, which involves black holes, but I won't go into those now. The point is that various scenarios for the distant future of the universe can be projected from assumptions in the model of how energy and matter behave relative to each other.

If, for example, all matter got transformed into EM radiation, would the radiation continue infinitely in divergent directions, or would it attract itself into convergent patterns? I think it would do the latter if space itself can indeed only exist as a function of gravitation, for in that case radiation itself would probably exert sufficient attractive force to generate curvature in its trajectory, which would probably eventually culminate in contraction to the point of forming new matter.

When you give the example of red-shift, are you implying that light loses energy by red-shifting? Why wouldn't you think that the waves are growing in amplitude in proportion to their frequency decrease? Couldn't a photon lose frequency simply be expanding, and therefore retain the same energy?

 

[nismaratwork]

You can analyze a model on whatever scale based on the assumption that all relevant parameters are known. If that assumption proves false, and it turns out that there are other influential parameters that you didn't take into account in your model, the model becomes that much less useful, but you can still attempt modeling and extrapolation from the model - it's not impossible.

What I would like to know is do you recognize space as being limited to gravitational topography, in the sense of Einsteinian curved spacetime, or do you presume space to exist independently of matter and its gravity? My assumption is that mass/gravity determines the curvature of space, and therefore it is never possible for EM radiation to escape matter indefinitely. Do you agree or do you think light can proceed infinitely away from any and all matter?

If matter is being converted into energy by stars everywhere, then presumably the mass of the universe is decreasing, unless there is some other process by which energy is getting converted into matter. I have personal hunches about how this could be happening, which involves black holes, but I won't go into those now. The point is that various scenarios for the distant future of the universe can be projected from assumptions in the model of how energy and matter behave relative to each other.

If, for example, all matter got transformed into EM radiation, would the radiation continue infinitely in divergent directions, or would it attract itself into convergent patterns? I think it would do the latter if space itself can indeed only exist as a function of gravitation, for in that case radiation itself would probably exert sufficient attractive force to generate curvature in its trajectory, which would probably eventually culminate in contraction to the point of forming new matter.

When you give the example of red-shift, are you implying that light loses energy by red-shifting? Why wouldn't you think that the waves are growing in amplitude in proportion to their frequency decrease? Couldn't a photon lose frequency simply be expanding, and therefore retain the same energy?

Here's a question for an answer: which is more energetic? A photon of the UV wavelength, or that of the Radio wavelength?

 

[brainstorm]

Here's a question for an answer: which is more energetic? A photon of the UV wavelength, or that of the Radio wavelength?

Wiki says radio waves are the least energetic and the lowest frequency. I do not understand what "photon" refers to exactly, i.e. whether it is a single EM wave or something else. The reason I thought it was decided that radiation behaved as particles is because energy is always delivered in fixed increments by radiation, which appear as packets. I think Planck discovered this, but I'm not 100%.

 

[nismaratwork]

Wiki says radio waves are the least energetic and the lowest frequency. I do not understand what "photon" refers to exactly, i.e. whether it is a single EM wave or something else. The reason I thought it was decided that radiation behaved as particles is because energy is always delivered in fixed increments by radiation, which appear as packets. I think Planck discovered this, but I'm not 100%.

My point is that light (in whatever form you choose to envision it) redshifts with universal expansion, which is true for all EM radiation, and in a sense, matter.