What is the fabric of space made of

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SUMMARY

The discussion centers on the nature of space and its composition, particularly questioning whether space is a void or made of something. Participants assert that space itself is not made of any material substance but is a mathematical construct, as suggested by Einstein's theories. They reference historical figures like Faraday, Maxwell, and modern concepts such as quantum fluctuations and Penrose Spin networks to illustrate the complexity of understanding space. The consensus is that while space may not be "nothing," it is not composed of tangible elements, challenging traditional views of physicality in relation to spacetime.

PREREQUISITES
  • Understanding of general relativity and its implications on spacetime.
  • Familiarity with quantum theory and concepts like quantum fluctuations.
  • Knowledge of historical figures in physics, such as Einstein, Faraday, and Maxwell.
  • Basic comprehension of mathematical constructs in physics, such as Penrose Spin networks.
NEXT STEPS
  • Explore the implications of general relativity on the nature of spacetime.
  • Research quantum fluctuations and their role in modern physics.
  • Study Penrose Spin networks and their theoretical applications in understanding space.
  • Investigate the historical context of Einstein's theories and their evolution over time.
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Students of physics, researchers in theoretical physics, and anyone interested in the philosophical implications of spacetime and the nature of reality.

planck
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What is space itself made of? i.e. if you take both your hands and put them in front of you--parallel to your shoulders, what is the empty space between your hands made of.

Is this space just a void? Did this area of space between your hands exist before the big bang. And if it didn't, didn't this space need to be created?
 
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The "fabric of space" is not made 0f anything- it is just space itself. No, space did not exist before the big bang, yes, it was created, along with everything else.
 
Faraday, Maxwell and Thomson believed that the space fabric consists of something, force or energy, under pressure which had a type of fluidic response to deformation. De Broglie, Dirac, Bohm, Casimir and Puthoff among others have all drawn some particular aspect of that primitive conception into more refined but also more abstract terms.

Would it be fair to say that Einstein reduced that away? In doing so did he remove the pieces of the model that are actually useful to understanding why it works the way it works?
 
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The theory that predicts the big bang (general relativity) doesn't say that space was created by the big bang. No theory does, at least no theory that's fully developed and experimentally distinguishable from general relativity. But I think a lot of people expect something like that to be a part of the "correct" quantum theory of gravity.
 
No one knows exactly what constitutes space...nor time, for example.

The "fabric of space" is not made of anything
as posted above

just doesn't seem complete to me ... after all, quantum theory correctly predicts the random emergence of particles and antiparticles from "nothing" (space) which to me suggests it is "something" ...and we know quantum fluctucations, and dark energy, reside there in the form of the cosmological constant...

One way to imagine space is as Penrose Spin networks...which can be drawn out from string theory...theoretical, of course, but a geodesic type construct with volumes and areas integers of Planck length represented via edges and nodes of the geodesic...(just think of a dome shaped roof with flexible edges and nodes...) ...Or maybe space are multidemensional strings...membranes in other words...

Another clue for me is that space and time are inextricably linked in relativity...and both are "flexible", that is undergo length contraction and time dilation at relativistic speeds..again hard for me to agree are "nothing" when they vary with speed. What further solidifies the idea that space IS something is that spacetime curves, its the geometric foundation for gravitational (force) via general relativity...gravitational potential molds spacetime...it curves light..odd were it " nothing"...

Newton talked of absolute space, Einstein improved that via concepts of absolute spacetime...in his theory of special relativity...
 
Physics = Mathematics (at least for TOE)
You don't ask 'what numbers are made of'?
The same here. Space is just a mathematical object.
 
Welcome to PF!

planck said:
What is space itself made of? i.e. if you take both your hands and put them in front of you--parallel to your shoulders, what is the empty space between your hands made of.

Hi Planck! Welcome to PF! :smile:

You may as well ask, what is time made of?

Time isn't made of anything, but we can still measure it. :-p

Why shouldn't space be exactly the same? :wink:
 
Would it be fair to say that Einstein reduced that away? In doing so did he remove the pieces of the model that are actually useful to understanding why it works the way it works?
Exactly, I agree... this is the problem in physics today. Einstein, I believe has set physics back 100 years not because what he developed is wrong but because it has gotten everyone else lost. It is impossible that a thing called space-time is affected by matter if space-time is actually nothing - nothing cannot be affected by something. Einstein was saying that we did not need to have a medium in order to describe what is happening - it is just a mathematical model which works. We can argue all day about what it is but this is a way to visualize and mathematically represent what is happening.
 
ZachN said:
It is impossible that a thing called space-time is affected by matter if space-time is actually nothing - nothing cannot be affected by something.

It depends on what you call a spacetime.
Spacetime in our universe can be affected by matter - but it is a brane and it is made of energy

In my first reply I meant an 'absolute' space(time?) of the Bulk (landscape)
 
  • #10
planck said:
What is space itself made of? i.e. if you take both your hands and put them in front of you--parallel to your shoulders, what is the empty space between your hands made of.

Is this space just a void? Did this area of space between your hands exist before the big bang. And if it didn't, didn't this space need to be created?
Spacetime is just the geometry of physics.
 
  • #11
ZachN said:
Einstein, I believe has set physics back 100 years not because what he developed is wrong but because it has gotten everyone else lost.
Relativity is not that complicated, lots of people understand it and are not "lost". I would challenge you to come up with any evidence supporting your claim that physics has been set back 100 years by Einstein.
 
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  • #12
It depends on what you call a spacetime.
Agreed. It may very well be energy. But it isn't "nothing" - as in an absolute vacuum or some abstract notion of space and time - it must be comprised of something or be represented by something.

But go talk to engineering and physics students at any level and I will bet you that they do not connect the idea of sapce-time with anything of "tangibility" (not that it must be something that we hold in our hands).

e.g. - I had a discussion with one of my physics TAs and he has taken relativity or at least an introductory course and electrodynamics, etc. In this case we were talking about the EM field, I asked him: "A field in what?(referring to the EM field)" His answer: "a field in space". Asking for more clarification I think he said something like the fabric of space-time. But essentially a circular answer and would not dare say that space-time was actually comprised of something (not energy, not ether, non alia).

But our problem, as the quote in my previous post states, is that we have churned out generations of physicists who have blocked out the very direction of thinking which will get us the answer. TV shows draw up that table-cloth image of space-time fabric and show how a piece of mass "warps" it. So everyone goes around thinking that there is an abstract 2D sheet of spandex that curls and twists in hyper-dimensional knots to create "space-time" which creates gravity and maybe other things.
 
  • #13
I agree with you that OUR spacetime is made of something (it is a brane)

But I insist that the fundamental (bulk) spacetime is not made of 'something'. You say

it must be comprised of something or be represented by something

and this is wrong because it creates an unlimited sequence of elephants/turtles staying on top of each. You claim that spacetime is made of something 'X', and that 'X' - what is made it of?

Look at mathematic systems. Peano arithmetics, for example. What is more fundamental - number 1 or + ?
 
  • #14
ZachN said:
Agreed. It may very well be energy. But it isn't "nothing" - as in an absolute vacuum or some abstract notion of space and time - it must be comprised of something or be represented by something.

But go talk to engineering and physics students at any level and I will bet you that they do not connect the idea of sapce-time with anything of "tangibility" (not that it must be something that we hold in our hands).
.

That's because when they use the word "space", they are not referring to the contents of the space, whatever they may be. They are just referring to the three dimensions (4 with space-time). The fact that the word space is not being used to refer to its contents doesn't imply that there are no contents.

Al
 
  • #15
ZachN said:
Exactly, I agree... this is the problem in physics today. Einstein, I believe has set physics back 100 years not because what he developed is wrong but because it has gotten everyone else lost. It is impossible that a thing called space-time is affected by matter if space-time is actually nothing - nothing cannot be affected by something. Einstein was saying that we did not need to have a medium in order to describe what is happening - it is just a mathematical model which works. We can argue all day about what it is but this is a way to visualize and mathematically represent what is happening.
That was very early on. By 1920 (Leiden Address) he said that an etheric space was needed for the propagation of EM, and the emergence of gravitational and inertial effects. He reiterated this again more forcefully in his 1924 essay "On the Ether". That essay is chapter 1 of "The Philosophy of Vacuum" - recommended reading.

Pricey, so a good excuse to visit a library.
https://www.amazon.com/dp/0198244495/?tag=pfamazon01-20
 
  • #16
ZachN said:
Agreed. It may very well be energy. But it isn't "nothing" - as in an absolute vacuum or some abstract notion of space and time - it must be comprised of something or be represented by something.

You are at odds with a phantom.

Einstein's Ether

http://physicsworld.com/cws/article/print/2384"

and

"It would have been more correct if I had limited myself, in my earlier publications, to emphasizing only the nonexistence of an ether velocity, instead of arguing the total nonexistence of the ether, for I can see that with the word ether we say nothing else than that space has to be viewed as a carrier of physical qualities." A. Einstein
 
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  • #17
Well, I agree with you all then. All I am saying is that a vast majority of physicists don't recognize an ether-like medium at all - they just think "space-time". I agree that Einstein did not intend to do away with a medium but that his work has accomplished that accidentally.

Looks like an interesting text - philosophy of the vacuum.
 
  • #18
ZachN said:
WLooks like an interesting text - philosophy of the vacuum.
It's "The Philosophy of Vacuum", edited by Saunders and Brown. Simon Saunders translated Einstein's essay from the German. Chapter 2 is an essay by Penrose. It's a great book - I'll have to buy a copy someday.
 
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  • #19
I'd like to think that the make-up of space has something to with the virtual particles that are popping in and out of existence in accordance with \Delta E\Delta t \ge \hbar/2 and that curvature might have something to do with a concentration of virtual particles around an object of mass.
 
  • #20
First of all, thanks to everyone for welcoming me to the forum and for contributing to my thread. You guys really know your physics so I'm going to enjoy reading your posts.

I'm not a physics major at all. I only took a high school physics class. But I've seen a ton of documentaries and read a bunch of michio kaku and brian green books.

Doesn't general relativity tell us that energy/matter warps space. So shouldn't that space be comprised of something.

But more importantly, why does the cubic volume of space between my hands that I mentioned in my initial post, have the ability to contain no density/mass. But in that same cubic volume, it has the ability to host a black hole.

Atoms and other particles of mass are allowed to freely move through that cubic volume of space, as einstein wrote:

"space has to be viewed as a carrier of physical qualities."

yet you can also fit a supermassive amount of particles in it also. Why is that possible?
 
  • #21
turbo-1 said:
It's "The Philosophy of Vacuum", edited by Saunders and Brown. Simon Saunders translated Einstein's essay from the German. Chapter 2 is an essay by Penrose. It's a great book - I'll have to buy a copy someday.

Good grief, turbo! I'd completely forgotten about your signature stuff under the line (what do they call it?) I just now noticed it in another thread. You've been putting it out there, all along.
 
  • #22
planck said:
Doesn't general relativity tell us that energy/matter warps space. So shouldn't that space be comprised of something.
Does it need to be comprised of something in order to have geometric properties such as distances and angles?
 
  • #23
If space is nothing why did it need the BB to create it?
 
  • #24
planck said:
I'm not a physics major at all. I only took a high school physics class. But I've seen a ton of documentaries and read a bunch of michio kaku and brian green books.
Ok, so you're probably as thoroughly confused as I was when I started researching and thinking about this stuff. :smile:

planck said:
Doesn't general relativity tell us that energy/matter warps space. So shouldn't that space be comprised of something.
Yes.

planck said:
But more importantly, why does the cubic volume of space between my hands that I mentioned in my initial post, have the ability to contain no density/mass. But in that same cubic volume, it has the ability to host a black hole.
There's at least some wave activity and interaction happening in any volume of space. Black holes are volumes where the wave activity is so intense and complex that current physics has no way to talk about exactly what's happening inside them.

planck said:
Atoms and other particles of mass are allowed to freely move through that cubic volume of space, as einstein wrote:

"space has to be viewed as a carrier of physical qualities."

yet you can also fit a supermassive amount of particles in it also. Why is that possible?
You might think about it in terms of interacting standing wave structures. If you have a tub of water and let the surface become calm and smooth, then set it to vibrating at a certain frequency, what do you see? Then increase the vibrational frequency, what do you see?
 
  • #25
If one thinks of the QG bounce, if space is nothing, nothing is contracting to a small radius,
and nothing expanding to a larger one, so nothing is happening?
 
  • #26
ThomasT said:
There's at least some wave activity and interaction happening in any volume of space. Black holes are volumes where the wave activity is so intense and complex that current physics has no way to talk about exactly what's happening inside them.
:confused: Most of a black hole is perfectly ordinary-looking. There is no local quality of space that can tell you if you're near, or even inside of a black hole. (especially if it's a large hole) Black holes can only be identified by studying a vast region of space-time that completely encompasses the black hole.
 
  • #27
Every thing is nothing.

http://www.astrosociety.org/pubs/mercury/31_02/nothing.html

Sort of strains the imagination, space is nothing, mass is nothing, energy is nothing.
 
  • #28
I'd like to think that the make-up of space has something to with the virtual particles that are popping in and out of existence in accordance with and that curvature might have something to do with a concentration of virtual particles around an object of mass.
Yes, a Concentration (of varying concentration - a density gradient) of virtual particles.

Sort of strains the imagination, space is nothing, mass is nothing, energy is nothing.
So all matter and energy is just our collective conscious agreeing that something of such and such form is "here" or "there". This is metaphysics.
 
  • #29
50% Cotton, 25% polyester and 25% Lycra Spandex.
 
  • #30
HallsofIvy said:
The "fabric of space" is not made 0f anything- it is just space itself. No, space did not exist before the big bang, yes, it was created, along with everything else.

This appears to be a contradiction to me. If space came with the big bang, then what was there before would be "nothing", thus space is "something".To the OP:

I don't think there's a well established answer to this question. If it interests you enough, maybe you can get a PhD in quantum field theory (or at least the equivalent education) and find the answer.

My point of view has always been that space is actually made of something, and further that the something is quantized. I predict this quantization might have something to do with the universal speed limit (speed of light), but these are wildly creative ideas lacking even anecdotal evidence
 

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