# How can space warp if it is a non-thing?

Discussion in 'Physics & Math' started by nicholas1M7, May 27, 2011.

1. ### SciWriterValued Senior Member

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Either space is a result of nothing that formed it as exactly the fluctuations that it actually is the same as, or space is absolute and its opposite left or right curvatures form the positive and negative charges and matter/antimatter states, there then only being space and its curving and nothing else besides that. Maybe. Why 3D though?

3. ### nicholas1M7BannedBanned

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Nothing encompasses everything, they are the same.

5. ### SciWriterValued Senior Member

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It would seem that everything could have no other source.

7. ### nicholas1M7BannedBanned

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Space can be thought of as being empty or void of anything.

8. ### keith1Guest

Void of anything large enough to disturb the perfect angled trajectories displayed by photons, in a Compton Scattering event.

9. ### RJBeeryNatural PhilosopherValued Senior Member

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This may have been addressed by other posts already but I didn't see the answer after a quick perusal: is it "functionally equivalent" (or maybe the term should be indistinguishable?) to consider gravity in GR as a warping of space-time or to consider empty space to be literally nothing, which cannot be "warped", but rather a result of the exchange of gravitons?

I've never liked the concept of warping space specifically (and only) for gravity; either all forces (gravity, EM, weak, strong) should be considered to be communicated via quantum particles, or they should all "warp space".

10. ### Farsight

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It's a "competing theories" issue, RJ. The classical electromagnetic field has curl, but people usually ignore it and talk instead about the virtual particles of QED as if they're real particles, then try to shoehorn the concept onto gravity.

Space isn't some empty nothing. Einstein said that in 1920:

"This space-time variability of the reciprocal relations of the standards of space and time, or, perhaps, the recognition of the fact that “empty space” in its physical relation is neither homogeneous nor isotropic, compelling us to describe its state by ten functions (the gravitation potentials gμν), has, I think, finally disposed of the view that space is physically empty".

And let's face it, space sustains waves and fields. A gravitational wave is considered to be a "travelling spacewarp", see LIGO. Electromagnetic waves involve displacement current, which you should take at face value: if you want to warp space, you have to displace it. But contemporary physics is so prey to those competing theories that you don't hear much about this kind of thing.

11. ### NietzscheHimselfBannedBanned

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Wow it took till the 1920's to figure out space exists. Such progress.

12. ### TachBannedBanned

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Back to citing the old Einstein Leiden address whose meaning you don't understand?

LOL

13. ### quantum_waveContemplating the "as yet" unknownValued Senior Member

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. You seem to be finding references to what might fill space and so let's conclude that no space is empty. It can just as easily be considered to contain energy. Contemplate the connection between energy waves and gravity, light, and matter. All are talked about here and there from the perspective of wave energy.

If matter is really wave energy contained in particles, particles form atoms and molecules, atoms and molecules are oscillating dipoles that emit light energy, and matter if we consider some sources, emits gravitational waves. So we have waves that compose matter, matter that emits light waves and gravity waves; space would be filled with wave energy.

14. ### RJBeeryNatural PhilosopherValued Senior Member

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I'm way too tired to completely digest your post...so you agree with me that, whatever reality is, all "force phenomena" should be analyzed in the same manner (i.e. either as a result of the exchange of quantum particles or as a warping of space / spacetime)?

15. ### Farsight

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Yes, they should be analyzed in the same manner. It doesn't make sense to take two different approaches and then end up with two irreconcilable formalisms.

I would say though that this "same manner" should start with something like: quantum particles are a warping of space, so it isn't quite an either/or choice between the exchange of quantum particles and the warping of space/spacetime.

16. ### AlphaNumericFully ionizedRegistered Senior Member

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As usual Farsight shows his ignorance.

In classical Maxwell's electromagnetism you have the vector potential A and then you get E and B via $F_{ab} = \partial_{a}A_{b}-\partial_{b}A_{a}$ with $F_{0i} = -E_{i}$ and $F_{ij} = \epsilon_{ijk}B_{k}$. This amounts to $E_{i} = -\partial_{i}A_{0} - \partial_{t}A_{i}$ and $B_{i} = \epsilon_{ijk}\partial_{j}A_{k}$, or more specicially $B = \nabla \times A$. This can all be written in a slick way using differential forms, $F = dA$.

In quantum electrodynamics it is EXACTLY the same, except that we now regard A as a quantised field rather than a classical field. The A is the vector potential for the photon. It's what the Lagrangian is written in terms of. In classical electromagnetism you have a Lagrangian of the form $F^{ab}F_{ab}$ and it is EXACTLY the same for quantised electromagnetism.

Generalisations via Yang Mills theory involve using the same A except that it isn't a U(1) gauge field, its a general gauge field. This amounts to $F = dA \to dA + [A,A]$. You can write electromagnetism like that too except that $[A,A] = 0$ because U(1) is a commutative Lie group.

Virtual particles come from the quantisation process, they are not some kind of replacement for the vector potential. The vector potentials are the quantum fields associated to particles. Photons, weak bosons and gluons all have vector potentials. Electrons, other leptons and quarks have spinor fields. They are what the Lagrangians are written in terms of!

Well done on showing you haven't got a clue as to what quantum field theory says but you're unwilling or unable to admit it. Instead you just put your foot in your mouth every time you post.

17. ### Farsight

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Despite the above, people really do talk about exchange particles as if they're real particles flying back and forth. See this post by Alphanumeric along with Feynman Diagrams and Forces Between Particles. One can gain an immediate appreciation of how misleading this is by considering pair production and the interaction between an electron and a positron. We start with a photon, an Aµ pulse propagating at c, and we divide it to create two dynamical rotational Aµ-pulse entities. There are no "Aµ pulses" zipping back and forth between the two.

18. ### AlphaNumericFully ionizedRegistered Senior Member

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You mean despite you having a huge gaping hole in your understanding of what mainstream physics says and that you're willing to just make things up in an attempt to somehow make your position more valid?

Unfortunately for you experiments disagree with you. And the vacuum virtual particles are the result of pair production, because its exactly the same principles. You can't have pair production in quantum field theory without virtual particles and virtual particles are the result of pair production (and other productions). They are intimately linked, not that you realise this given you have no idea how such results are arrived at in quantum field theory.

Ah, so now that I've explained to you that infact the vector potential and its curl does exist within quantum field theory, in direct contradiction to your previous claims, suddenly you start talking about it in quantum field theory. Wow, are your attempts to back peddle transparent! And even then you get it wrong.

Pair production, in regards to a photon turning into an electron/positron pair is not the conversion of a vector potential $A_{a}$ into two other vector potentials. Electrons, as I said, are spinors and thus do not have vector potentials, $A_{a}'$, they have spinor potentials. The index structure is different because the transformation structure is different, even the dimensionality is in general different.

You didn't know what quantum field theory said about potentials, you made a claim, I corrected it, you made an attempt to back peddle and I've had to correct you again. Don't you EVER learn? If you don't know something don't say anything. You have a long history of making claims about mainstream physics and being called on them. It might work with your family or friends but when you try it on a physics forum in conversation with physicists you're just asking to be exposed as a liar. And once again that is precisely what has happened.

19. ### RJBeeryNatural PhilosopherValued Senior Member

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@AlphaNumeric: so QED is just as it sounds, a quantized field generated by particles rather than a continuous entity with any external existence of its own. What I'm asking is, can we consider gravitons to offer an equivalent explanation of gravity that would be indistinguishable from Einstein's warping of space?

I've never liked warping space to explain GR and I just want to know if Einstein took that route because "the math worked", or if he took that route because it is an unavoidable conclusion that, in his words, GR "finally disposed of the view that space is physically empty".

20. ### Farsight

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He didn't actually take that route, RJ. Look carefully at the full quote above, he was talking about inhomogeneous space. It isn't distorted or "warped", its properties aren't uniform. As a result light travels in a curved path through it. We call the result "curved spacetime", but it isn't the same thing as curved space. Note that Einstein didn't talk about curved spacetime, that's something that's crept in since his day, see http://arxiv.org/abs/physics/0204044 for more information.

21. ### RJBeeryNatural PhilosopherValued Senior Member

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Yes you're right I'm conflating space with spacetime. To me, though, inhomogeneous space is equivalent to saying that space is not empty. If it has properties that are not uniform then it is clearly "something". Is the concept of a vacuum being truly empty incompatible with the implications of GR?

22. ### Farsight

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There's no huge gaping hole in my understanding, and I'm not making anything up. The links I gave to your post on gravitons and Feynman Diagrams and Forces Between Particles aren't fiction. You said:

"Except that there are gravitons moving around in that region. A quantum field theory vacuum is not a classical vacuum, it always has particles within it (if you'd like a few page references for Peskin & Schroeder I can provide them). Furthermore the space-time itself is some seething mass of gravitons knitted together..."

That is fiction. And it's risible.

The experiment confirms that space is not empty, and like the Casimir effect demonstrates the existence of vacuum fluctuations. As I said here we can liken these to random ripples on the surface of an ocean, but we don't actually see short-lived electrons and positrons. The DCE concerns photons, not electrons and positrons flitting in and out of existence, and not your precious seething gravitons. What was it you said to Magneto?

"Besides the paper isn't saying that, as your link use of a link implies the paper is justifying your model, which it isn't".

It doesn't justify electrons and positrons flitting in and out of existence either.

Electron-positron pair production is real, but to say that the photon-photon interaction that yields an electron and a positron, is the result of virtual particles that are the result of pair production displays muddled circular thinking.

That's one way to try to defend the specious garbage that pair production is the result of pair production. Shame it doesn't work.

You've explained nothing, you never do, all you do is throw out outraged insults. I said:

"The classical electromagnetic field has curl, but people usually ignore it and talk instead about the virtual particles of QED as if they're real particles, then try to shoehorn the concept onto gravity".

That's what you've been doing. How embarrassing.

Read what I said. And appreciate that you have no idea what a vector potential or a spinor potential actually is in terms of the underlying reality. Pair production transforms a photon (interacting with a nucles) or two photons into an electron-positron pair, or some other pair. The electron has spin angular momentum and magnetic dipole moment. Ditto for the positron. Annihilate the electron with the positron and you've got two photons. But you can't explain how these transformations occur. Thus the gaping hole is in your understanding.

Spare me the howls of outrage. You didn't correct me, I didn't backpeddle, and it isn't me being exposed here. And please, don't give me all your usual arrogant "mainstream physics" claptrap in an attempt to distract from your embarrassment at being caught out talking about gravitons as if they're real particles. Contribute usefully to this topic and stop wasting everybody's time.

23. ### Farsight

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Easily done. There's a lot of material out there that talks about spacetime as if it's space, forgetting that there's no motion in spacetime. A worldline represents the motion of an object through space over time. But the object doesn't move up the worldline. The worldline is a static "all-times view" representation. This is quite a good read by the way: Nasty Little Truth About Spacetime Physics. He lays it on a bit thick, but he isn't wrong.

I agree. That's what Einstein said, and regardless of that, space sustains fields and waves. When we see a wave in the ocean we say the ocean is waving. When we see a wave in a rubber mat we say the rubber mat is waving. But for some reason people talk about a wave in space and insist that it isn't waving. Even people who you'd expect to know about LIGO and have read the original Maxwell. It's the displacement current thing again, this kind of thing:

"Maxwell concluded, using Newton's equation for the speed of sound (Lines of Force, Part III, equation (132)), that “light consists of transverse undulations in the same medium that is the cause of electric and magnetic phenomena”.

I'd say so, though maybe I prefer space is something rather than nothing. The gravitomagnetic "space-time vortex" is an implication of GR. If space was truly empty, you couldn't twist it like that. This is what's happening with plain-vanilla electromagnetism by the way - gravitomagnetism isn't wholly different. Maxwell didn't get it all right, but take a look at On physical lines of force and note that he's talking about "molecular vortices". Sadly he died aged 48 just as people were finding out about electrons.