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What is Space made of?


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What is space made of??

I don't think that Einstein said that there is no aether. I think i read that he said that SR & GR do not need an aether.

Although almost certainly if there is an aether then SR cannot be, & if SR cannot be then GR falls also.

On the other hand if SR & GR exist, then perhaps they don't necessarily disqualify the existence of some sort of aether.

 

I believe in a sub-quantum aether, that is the foundation of the universe, & is thusly ponderable (ie not only can we see its handiwork, we can measure its vel).

 

But we might all be wrong, what if some sort of sub-quantum aether existed that had no connection to our quantum world. It would be completely imponderable, & non-knowable, & i guess irrelevant. Just thinking out loud.

Edited by madmac
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observable i'm using a new interpretation(that i made up) that means only thing observable by the human eye exist in it   and black holes basically suck light it "prevents" it escaping but i

I guess the answer is science doesn't know. Why guess?

Nope , you are now confusing 'science' and 'technology". Despite popular opinion, the two have nearly nothing to do with each other. And sometimes , 'technology' helps 'science' a bit forward. Bu

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..................... It's here , I start to come unstuck ... Somehow ....?

..your ....

 

 

...

We can equally assign different coordinates to different points in your electro-magnetic field however that doesn't mean those coordinates gain a medium quality. The electromagnetic field itself not its coordinate field is what exhibit the medium qualities.

 

So Spacetime curvature under GR is the collection of vector relations where we set the geometry as the free-fall motion.

 

A geodesic is describing a free fall motion at every coordinate with the use of vectors via the stress tensor between two points. This is what space-time curvature (under GR) is describing a collection of vectors at each coordinate. In accordance to the Principle of least action (kinematic motion under free fall).

 

This is also why we use inertial frames in SR (key word inertial)

 

Now a medium induces further delays in the kinematic motion of two particles. So if space-time was a medium we would have further delays. It would be the same as placing additional resistance to the electromagnetic example above. Recall the word Impedance in your electromagnetic theory. Mass is a form of impedance it is impedance to kinematic motion. impedance=resistance.

 

Now using the electromagnetic field once again. You may recall that two circuits with two electromagnetic fields can induce impedance upon each other (propogation delay) we can describe these delays via coordinate time if we assign coordinates to each point of each field. See where I am going with in time dilation ?

 

If every particle is a field excitation then time dilation itself is by analogy a form of propagation delay. Just as it is in the electromagnetic field theory.

 

(keep in mind the above is a simpification) A heuristic rudimentary means to understand space-time under familiar terms. I won't try to show that gravity is not a force under GR using kinematic action as I know your not ready for that level of mathematical detail. However it does include everything I described above in particular the principle of least action under space-time curvature

As I indicate above " about here in your explanation I start to become unstuck " ...?

Edited by Mike Smith Cosmos
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How simple it would be to unify physics if massless energy could create mass.

Imagine the big bang as quantum bubble spewing out fundamental energy particles that were massless.

Inflation would be no problem as they could quantum leap faster than light.

There would be no issue with gravity as it wouldn’t exist in a massless universe.

As the fundamental energy particles began to cool they would bond together to form sub atomic particles and then atoms.

Any fundamental energy particles that didn’t bond would form back ground radiation.

The atomic forces and speeds of electrons, protons and neutrons would create ‘motion mass’, this would facilitate gravity and stars could be born.

How simple it would be if mas was really ‘motion mass’, created from massless energy.

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First, welcome to the forum. I am glad to see you are interested in science and have some imaginative ideas. But ...

 

How simple it would be to unify physics if massless energy could create mass.

 

 

Well, mass and energy are equivalent. So energy can be converted into mass. For example, a photon can turn into an electron and a positron. Or, more significantly, nearly all the mass of protons and neutrons comes from the energy holding them together, not from the mass of the quarks they are made of.

 

 

 

Imagine the big bang as quantum bubble spewing out fundamental energy particles that were massless.

 

That is not how the big bang model works. Your description sounds like the is this "quantum bubble" in empty space. In the big bang model, instead, space has always been completely (and homogeneously) full of matter and energy. But space has expanded so that the matter and energy has cooled over time.

 

 

Inflation would be no problem as they could quantum leap faster than light.

 

There is no way for particles (with or without mass) to move faster than light.

 

 

There would be no issue with gravity as it wouldn’t exist in a massless universe.

 

But mass and energy are equivalent so the energy of a system contributes to its gravitation.

 

 

How simple it would be if mas was really ‘motion mass’, created from massless energy.

 

I don't know what "motion mass" is. But it really isn't that simple.

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What is space made of??

I don't think that Einstein said that there is no aether. I think i read that he said that SR & GR do not need an aether.

[..]

 

Hi Madmac probably you arrived when I took an extended holiday. That issue was elaborated in the following threads:

http://www.scienceforums.net/topic/97105-is-space-time-a-physical-entity-or-a-mathematical-model/page-11#entry943184

http://www.scienceforums.net/topic/98845-models-for-making-sense-of-relativity-physical-space-vs-physical-spacetime/

 

In a nutshell, the experimental support for theory (SR, GR, QM) apparently obliges us to accept that Space is not merely a mathematical concept that relates to nothingness. But what is it made of? I'm afraid that the definite answer to that question may always be beyond our reach.

 

Currently, the only thing we can do is to invent models. A promising looking route was that of unifying field theories, but as far as I know, a well developed and satisfying theory is still wanting (although there are some around that seem to have potential).

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Why does it have to be made of anything?

Hello everyone,

 

I am very interested into this topic because, but my answer would require the study of different concepts before being understood clearly enough.

 

Someone did say a very clever thing:"

Why does it have to be made of anything?"

 

The answer is in the question.

 

Human can't represent themselves nothing when it's shown 24h over our head. Did anyone get why Einstein was interested into Brownian movement?

Judt saying that "nothing is real". It means "Nothing" is "Real"!!!!

 

We re so screwed with just words to explain a truth which existed before the word being created....

 

Fyi: e=mc2 works for both ways:" dématérialisation and materialisation

When i think mankind has been waiting for Einstein to know about relativity...

 

The universe is continuous and relativity manage all relative moving things.

There are maths our consciousness can deal with perfectly, which are static maths.. if a car start form A at 12:00 and another car etc..?

These are moving véhicules but the maths are static. Every answer will be ask regarding a certain time!

 

Defining the notion of point on something contious as time??? There is no point in our universe!!

The only point is our universe itself!!!

 

 

So you can averagely know the answer to a question you thought that was easy before...

 

 

So Space is made of nothing until provrn otherwise by observation, ok?

 

Shroedinger's cat bloody hell!!!

 

Sorry, i had to let this out. All the best guys!

 

Thanks.

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Did anyone get why Einstein was interested into Brownian movement?

 

 

He was interested in many things. And it was an unsolved problem at the time. What is your point?

 

 

 

Judt saying that "nothing is real". It means "Nothing" is "Real"!!!!

 

Incoherent nonsense.

 

 

 

We re so screwed with just words to explain a truth which existed before the word being created....

 

Luckily, science has mathematics rathe than just words. As your words are largely nonsensical, I'll stick with the science.

 

 

 

When i think mankind has been waiting for Einstein to know about relativity...

 

... and what? That is a pretty pointless statement.

 

But we weren't really waiting for Einstein. Others, such as Galileo, Maxwell, Poincare, Lorentz, Hilbert, Minkowski, etc. laid the groundwork and almost anyone from Maxwell onwards could have come up with the same results as Einstein.

 

 

 

The universe is continuous

 

You don't know that. There are many theories being developed based on the idea that space (and time) is quantised.

 

 

 

Sorry, i had to let this out.

 

You needn't have bothered. It was a waste of your time and ours.

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  • 3 months later...

Shouldn't we be calling it spacetime?

"The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality".

Hermann Minkowski

My own view on this is that space, time, spacetime, while certainly not physical, are real....just as a magnetic field is real.

Space is what stops everything from being together.

Time is what stops everything from happening together.

Spacetime is the unified multi-dimensional framework within which we locate events and describe the relationships between them in terms of spatial coordinates and time. The concept of spacetime follows from the observation that the speed of light does not vary with the motion of the emitter or the observer. Spacetime allows a description of reality that is common for all observers in the universe, irrespective of their relative motion.

Each frame of reference when considered separately, sees space and time differently, but spacetime is invariant.

Spacetime is geometry.

In GR gravity is described in terms of curvature of spacetime.

Space, time, spacetime while being real, are not made of anything.....space and time, "as we know them" came into existence at the BB.

 

Anyone see anything wrong with those definitions?

Edited by beecee
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The reason I used space as opposed to spacetime is that the most common misconception is trying to apply some substance like property to volume.

 

 

The typical question is "what is space or spacetime made of and how does it curve?.

 

They do that to try to understand what curves, which is reflected in your time coordinate under 4d. Obviously there is no curvature under 3d Galilean.

 

So I figured it was better to stress the 3d Galilean relativity first, then add the time component.

 

After all the only change is the addition of the time coordinate. So if you define a 3d Space as volume filled with SM particles. Why would adding a time coordinate change what space is comprised of ? Obviously it doesn't

 

Spacetime by definition is "any metric system describing space/volume with the addition of the time coordinate as a vector".

 

Though at some point I will be rewriting the first post to include several of the suggestions on this thread.

Edited by Mordred
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If space is just volume, how do reconcile 'quantum foam' or are you intending to make a clear distinction between what GR says and QP says?

Space is made out of of a particle that is call noting because we cannot see it and cannot detected and will become something = matter

throughout presses of matter and that involving fusing action (not reaction )= fission

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Space is made out of of a particle that is call noting because we cannot see it and cannot detected and will become something = matter

throughout presses of matter and that involving fusing action (not reaction )= fission

So far, space has not been found to be quantised; It's smooth AFAIK. It's just volume with things in it.

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The typical question is "what is space or spacetime made of and how does it curve?.

 

 

 

And how or why does mass/energy alter the geometry of flat spacetime.

My mind wanders to one of the greatest experiments on Earth being conducted now at the LHC and the "Higgs particle" and Higgs field......I'm fairly raw on knowldege of the Higgs particle and field, but hypothetically, could this be why mass/energy warps spacetime?

I hope this isn't sidetracking, but I'm attracted to the possible "Superforce", when all the forces were united just after the BB with the extremely high energy levels existent at that time.

Is there a possible connection between the Higgs and associated field, and the Superforce and graviton?

I know we havn't yet achieved a QGT, but there does seem to be some evidence as to why the aforementioned hypotheticals maybe valid....

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|If one uses! it's imagination and + it's hallucination perhaps logic will relieved what? makes the best of it's understandding.

Your imaginings and hallucinations are worthless without evidence.

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And how or why does mass/energy alter the geometry of flat spacetime.

My mind wanders to one of the greatest experiments on Earth being conducted now at the LHC and the "Higgs particle" and Higgs field......I'm fairly raw on knowldege of the Higgs particle and field, but hypothetically, could this be why mass/energy warps spacetime?

 

All forms of energy or fields attribute to curvature. Mass being resistance to inertia change. Any binding force or other field interactions induce delays in signals or information exchange between particles.

Higgs field interacts with only certain particles. w+, w-, z boson. Through their mediation quarks gain a mass term.

Even if you isolate every field and still look individually at each fields interactions you will always have a energy/momentum stress tensor influence upon spacetime curvature. It does not matter what field you use.

 

Each field has an effective equation of state that gives us a potential energy to kinetic energy relation. [latex]w=\frac{p}{\rho}[/latex] pressure is also a term in the stress tensor. (force per unit volume).

 

I always found the expression " spacetime curvature is the sum of delays due to interparticle interactions" a handy way to make sense of time dilation itself as well as the curvature term.

 

A handy method to make sense of that expression is under action. In this post for example I show the relations between e=mc^2 etc to force and action.

 

I am developing a list of fundamental formulas in QFT with a brief description of each to provide some stepping stones to a generalized understanding of QFT treatments and terminology. I invite others to assist in this project. This is an assist not a course. (please describe any new symbols and terms)

 

QFT can be described as a coupling of SR and QM in the non relativistic regime.

 

1) Field :A field is a collection of values assigned to geometric coordinates. Those values can be of any nature and does not count as a substance or medium.

2) As we are dealing with QM we need the simple quantum harmonic oscillator

3) Particle: A field excitation

 

Simple Harmonic Oscillator

[latex]\hat{H}=\hbar w(\hat{a}^\dagger\hat{a}+\frac{1}{2})[/latex]

s

the [latex]\hat{a}^\dagger[/latex] is the creation operator with [latex]\hat{a}[/latex] being the destruction operator. [latex]\hat{H}[/latex] is the Hamiltonian operator. The hat accent over each symbol identifies an operator. This formula is of key note as it is applicable to particle creation and annihilation. [latex]\hbar[/latex] is the Planck constant (also referred to as a quanta of action) more detail later.

 

Heisenberg Uncertainty principle

[latex]\Delta\hat{x}\Delta\hat{p}\ge\frac{\hbar}{2}[/latex]

 

[latex]\hat{x}[/latex] is the position operator, [latex]\hat{p}[/latex] is the momentum operator. Their is also uncertainty between energy and time given by

 

[latex]\Delta E\Delta t\ge\frac{\hbar}{2}[/latex] please note in the non relativistic regime time is a parameter not an operator.

 

Physical observable's are operators. in order to be a physical observable you require a minima of a quanta of action defined by

 

[latex] E=\hbar w[/latex]

 

Another key detail from QM is the commutation relations

 

[latex][\hat{x}\hat{p}]=\hat{x}\hat{p}-\hat{p}\hat{x}=i\hbar[/latex]

 

Now in QM we are taught that the symbols [latex]\varphi,\psi[/latex] are wave-functions however in QFT we use these symbols to denote fields. Fields can create and destroy particles. As such we effectively upgrade these fields to the status of operators. Which must satisfy the commutation relations

 

[latex][\hat{x}\hat{p}]\rightarrow[\hat{\psi}(x,t),\hat{\pi}(y,t)]=i\hbar\delta(x-y)[/latex]

[latex]\hat{\pi}(y,t)[/latex] is another type of field that plays the role of momentum

 

where x and y are two points in space. The above introduces the notion of causality. If two fields are spatially separated they cannot affect one another.

 

Now with fields promoted to operators one wiill wonder what happen to the normal operators of QM. In QM position [latex]\hat{x}[/latex] is an operator with time as a parameter. However in QFT we demote position to a parameter. Momentum remains an operator.

 

In QFT we often use lessons from classical mechanics to deal with fields in particular the Langrangian

 

[latex]L=T-V[/latex]

 

The Langrangian is important as it leaves the symmetries such as rotation invariant (same for all observers). The classical path taken by a particle is one that minimizes the action

 

[latex]S=\int Ldt[/latex]

 

the range of a force is dictated by the mass of the guage boson (force mediator)

[latex]\Delta E=mc^2[/latex] along with the uncertainty principle to determine how long the particle can exist

[latex]\Delta t=\frac{\hbar}{\Delta E}=\frac{\hbar}{m_oc^2}[/latex] please note we are using the rest mass (invariant mass) with c being the speed limit

 

[latex] velocity=\frac{distance}{time}\Rightarrow\Delta{x}=c\Delta t=\frac{c\hbar}{mc^2}=\frac{\hbar}{mc^2}[/latex]

 

from this relation one can see that if the invariant mass (rest mass) m=0 the range of the particle is infinite. Prime example gauge photons for the electromagnetic force.

 

Lets return to [latex]L=T-V[/latex] where T is the kinetic energy of the particle moving though a potential V using just one dimension x. In the Euler-Langrange we get the following

 

[latex]\frac{d}{dt}\frac{\partial L}{\partial\dot{x}}-\frac{\partial L}{\partial x}=0[/latex] the dot is differentiating time.

 

Consider a particle of mass m with kinetic energy [latex]T=\frac{1}{2}m\dot{x}^2[/latex] traveling in one dimension x through potential [latex]V(x)[/latex]

 

Step 1) Begin by writing down the Langrangian

 

[latex]L=\frac{1}{2}m\dot{x}^2-V{x}[/latex]

 

next is a derivative of L with respect to [latex]\dot{x}[/latex] we treat this as an independent variable for example [latex]\frac{\partial}{\partial\dot{x}}(\dot{x})^2=2\dot{x}[/latex] and [latex]\frac{\partial}{\partial\dot{x}}V{x}=0[/latex] applying this we get

 

step 2)

[latex]\frac{\partial L}{\partial\dot{x}}=\frac{\partial}{\partial\dot{x}}[\frac{1}{2}m\dot{x}^2]=m\dot{x}[/latex]

 

which is just mass times velocity. (momentum term)

 

step 3) derive the time derivative of this momentum term.

 

[latex]\frac{d}{dt}\frac{\partial L}{\partial\dot{x}}=\frac{d}{dt}m\dot{x}=\dot{m}\dot{x}+m\ddot{x}=m\ddot{x}[/latex] we have mass times acceleration

 

Step 4) Now differentiate L with respect to x

[latex]\frac{\partial L}{\partial x}[\frac{1}{2}m\dot{x}^2]-V(x)=-\frac{\partial V}{\partial x}[/latex]

 

Step 5) write the equation to describe the dynamical behavior of our system.

 

[latex]\frac{d}{dt}(\frac{\partial L}{\partial\dot{x}}-\frac{\partial L}{\partial x}=0[/latex][latex]\Rightarrow\frac{d}{dt}[/latex][latex](\frac{\partial L}{\partial\dot{x}})[/latex][latex]=\frac{\partial L}{\partial x}\Rightarrow m\ddot{x}=-\frac{\partial V}{\partial x}[/latex]

 

recall from classical physics [latex]F=-\triangledown V[/latex] in 1 dimension this becomes [latex]F=-\frac{\partial V}{\partial x}[/latex] therefore [latex]\frac{\partial L}{\partial x}=-\frac{\partial V}{\partial x}=F[/latex] we have [latex]m\ddot{x}-\frac{\partial V}{\partial x}=F[/latex]

The principle of least action also defines your null and spatial freefall geodesics for your curvature term.

 

Apply the above for the standard model of particles including the Higgs field under action via

 

 

[latex] \stackrel{Action}{\overbrace{\mathcal{L}}} \sim \stackrel{relativity}{\overbrace{\mathbb{R}}}- \stackrel{Maxwell}{\overbrace{1/4F_{\mu\nu}F^{\mu\nu}}}+\stackrel{Dirac}{\overbrace{i \overline{\psi}\gamma_\mu\psi}}+\stackrel{Higgs}{\overbrace{\mid D_\mu h\mid-V\mid h\mid}} +\stackrel{Yukawa-coupling}{\overbrace{h\overline{\psi}\psi}} [/latex]

 

and voila you just incorporated every SM field into your spacetime curvature using action. Every field contributes in some fashion.

Edited by Mordred
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...

Apply the above for the standard model of particles including the Higgs field under action via


[latex] \stackrel{Action}{\overbrace{\mathcal{L}}} \sim \stackrel{relativity}{\overbrace{\mathbb{R}}}- \stackrel{Maxwell}{\overbrace{1/4F_{\mu\nu}F^{\mu\nu}}}+\stackrel{Dirac}{\overbrace{i \overline{\psi}\gamma_\mu\psi}}+\stackrel{Higg's}{\overbrace{\mid D_\mu h\mid-V\mid h\mid}} +\stackrel{Yugawa-coupling}{\overbrace{h\overline{\psi}\psi}} [/latex]

and voila you just incorporated every SM field into your spacetime curvature using action. Every field contributes in some fashion.

 

Excellent post as always Mordred. And because I could never contradict you on physics, I will take this opportunity to take a mild shot at your nomenclature >:D

 

It's Yukawa coupling and Higgs (no apostrophe; named after him not his possessive - which would mean anyway that the apostrophe would be after the s )

 

Now awaiting the Skitt's Law moment... :P

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  • 2 weeks later...

This has to be one of the most interesting threads on this forum.

 

Questions Does space only exist because it is full of fields. With no fields there is no space time. Space and time being variables to give the distance between fields, which if they didnt exist space time would not exist.

 

How can space be curved without fields, how can a volume exist without a field or reference point to measure from.

 

Can an infinte space full of fields of one form or another exist at the same time as an empty space full of nothing, would the emopty space be zero volume.

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Questions Does space only exist because it is full of fields. With no fields there is no space time. Space and time being variables to give the distance between fields

 

They aren't variables, it's the field in which variables happen.

Edited by dimreepr
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