What is the fabric of space made of

tiny-tim

ah …

Phrak

For more stuff-like, than property-like space, you might want to look at this thread.

http://www.physicsforums.com/showthread.php?t=281754

Chrisc

There is no fabric of space, mass is the "fabric", woven from the
Warp(space) and Weft(time) that is the geometry of GR.
That's why space is Warped when there is no time Weft you silly wabbit.

DaleSpam

My apologies in advance for the boring and pedantic grammar instruction.No, "distances" and "angles" are nouns. The noun "distances" can be paired with a definite article "the distances" whereas adjectives cannot (e.g. "the red") and can be paired with an adjective "large distances" whereas a verb cannot (e.g. "large see"). Try the sentences: "The distances increased" and "The angles summed to 270º".

ThomasT

The experiment I suggested illustrates one way to approach the issue that you brought up, "you can also fit a supermassive amount of particles in it also. Why is that possible?"

That's a mathematical model. What space IS, in reality, is anybody's guess. My guess is that any volume is pervaded and permeated by all sorts of wave activity -- and that the medium or media in which that wave activity is occuring is what space IS. Maybe all detectable particulate media are byproducts of some fundamental seamless medium. Is that what you're wondering about? This stuff will remain speculative even if it's a logical extension of what's known.

I don't understand your other questions.

Dmitry67

I think the reason why people are asking 'what space is made of?' is because of the intuitive perception that if something spacial is not made of something, it does not have a structure to support itself and collapses.

This is 'wired' (hardcoded) in our brain like the Neuton mechanics. Just compare, time and space are almost the same things but people ask about space 'what it is made of'? and regarding time they tend to ask different questions like 'is time actually moving'? etc.

This example illustrates that the 'requirement' that 'space must consist of something' to exist is nothing more then a naive vision based on our everyday experience and so called 'common sense reasoning'

When something is too abstract to deal with it in our everyday life people do not ask such questions, for example, people do not ask 'what energy is made of'? For the pure energy people somehow accept that it can just exist, without being consists of anything else.

Fra

I throw in some thoughts to fuel the fire.

This isn´t such a bad rational as it might first seem. I think it suggest an answer.

What are questions made of? What supports a question? All questions is based on premises, necessary for the very formulation of the question. Questions don´t float in space, that depend on questioners, and I personally often thing of the essence of a question, as a property of the state of the questioner.

The original example of two hands beeing a boundary of the void. The question of what is the void, is pretty much the same question as what is the relation between the hands? or the distributed boundary? would it be possible to even pose the question of what is the void between the hands if the hands weren't there?

So the idea of pure space (pure gravity) is possible as strange as to ponder matter with no place to "sit". I often think of it as two sides of the same coin.

Olaf Dreyers, having some own ideas in "internal relativity" phrases it like this

"In our view, matter and geometry have a more dual role. One can not have one without the other. Both emerge from the fundamental theory simultaneously"
-- http://arxiv.org/abs/0710.4350

I guess what he says that there is little hope to find a consistent theory of say PURE gravity. Because the matter parts are required for consistency. I see this closely related to other obvious things, like that questions always live in a context. Measurements always live in context. The idea of ponder measurements, without an observers is to me the weirdest of all.

So my conclusion is that to ask what is spacetime is inseparable from the question what is matter, and how matter relates to itself.

So the question of what matter "is" in the mechanical sense might be a bad choice of question, but I would suggest the answer closest matching the question is that geometry is simply a state of matter. Then again, we are lead to ask what is matter. And they are related in an evolving relation.

/Fredrik

Dmitry67

Interesting, but I am a fanatical adept of another religion :)

http://arxiv.org/abs/0704.0646
The Mathematical Universe
Authors: Max Tegmark

Let me give you some quotes regarding the subject we discuss (but it is much better to read the whole article):

So all these questions like "Does time actually flows? What space is made of? What is a vacuum? What is matter?" these questions are all about the "baggage" so in the ultimate sense they dont have any sense at all.

Chrisc

This sounds like a "theory" of mathematics that requires the "baggage" it denies to support it's claims.

Dmitry67

No, read the chapter "Physics from scratch"

jambaugh

My view is that space is not a physically existent object so the question is meaningless. Space is our conceptualization of the relationships (with regard to interaction) of physical objects/systems. It is no more real (and no less essential) than say abstract numbers.

Fra

I've read that paper before. Interesting, but I don't see the clear utility of the abstraction he advocates.

Put shortly, my main general objection is that he is focusing on the so called birds view (also called the external view). This is to me, a way of reasoning that is old, I tried it and it didn't work for me This external reality, as seen from a fictive omnipresent and unconstraint observer (the "bird") is an abstraction that IMHO lacks physical motivation.

I favour the opposite, I consider the intrinsic view to be the scientifically motivated one. I see the external views to be emergent, but always in evolution.

I think that since Tegemark is unlikely to actually find and nail such an external view and moreover to communicate it to his fellow frog scientists, his choice is focus is totally akward to me. He seems to be an extreme reductionist. I am probably more like those solipsists that will reject his ERH.

My reason for rejection is that the hypothesis seems to me to lack utility unless that external mathematical structure is found. His hypothesis doesn't as far as I see help in finding it. Therefore I question the utility of his hypothesis.

/Fredrik

planck

I'm not entirely sure what you are trying to illustrate with the vibrating tub of water, then. I'm correlating the water in the tub to being the medium in which objects in the tub are able to move in--much like the space I'm talking about.

So if space is merely "nothing," as some on this thread are suggesting. Then, wouldn't it be safe to assume:

1) Space had always existed, much like a solid-state, even before the big bang.

2) The big bang only introduced matter/energy into the universe.

3) Space is infinite.

Dmitry67

For the spacetime of our universe (a brane) answers are:
1. no
2. no
3. probably yes

For the 'bulk' space
1. yes
2. n/a
3. yes

wolram

Is fabric even the right word for space? fabric implies structure and AFAIK no one has found any structure to space.

ThomasT

Yes, the water is the analog of your space (or at least some media component of it), and depending on the vibrational frequency you see more or different particles, or more energetic wave behavior and more complex wave interaction -- different interference effects. I was just suggesting one approach to how a given volume could hold more and more particles. Just spitballing -- my two cents.

Or maybe there is a fundamental (seamless and therefore undetectable, fapp nothing) medium, from the agitation of which a hierarchy of detectable disturbances and media emerge, and it's some sort of mixture of all that that pervades and permeates the spatial volume defined by the boundary of our universe (if it has a boundary ... I think it's reasonable to assume that it does ... but who knows).

Not necessarily safe , but it does seem reasonable to assume some sort of fundamental medium that our universe is a disturbance in.

It seems reasonable to assume some humongous initiating disturbance that shook up the existing medium and imparted a humongous amount of kinetic energy.

stevebd1

An interesting overview from 'Special & General Relativity Questions and Answers' from the Gravity Probe B website (Credit to Naty1 for posting the link in this thread)-


If space exists, what is it?

This is the single most important question in modern physics. Einstein himself said that so far as his general relativity is concerned, space (actually space-time) and the gravitational field are the SAME THINGS. We see it as something that is empty because, in modern language, we cannot see the quantum particles called gravitons out of which it is 'manufactured'. We exist much like the raisins in a bread, surrounded by the invisible but almost palpable 'dough' of the gravitational field. In many respects there is no difference between the field that we are embedded in and the apparently solid matter out of which we are made. Even at the level of quarks, over 95 percent of the 'matter' that makes up a 100 kg person is simply locked up in the energy of the gluonic fields out of which protons are fashioned. The rest is a gift from the way quarks and electrons interact with a field called the Higgs field which permeates space. We are, really and truly, simply another form of the gravitational field of the universe, twisted by the Big Bang into a small family of unique particle states.