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Thread: What do electromagnetic waves "ride on"?

  1. #1 What do electromagnetic waves "ride on"? 
    Forum Freshman .o:0|O|0:o.'s Avatar
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    Does anyone actually know how EM waves propagate through space?

    They have alternating oscillating electric field and magnetic field components, they vary in frequency/ wave-length and have many curious behavioural characteristics (wave-particle duallity for photons), but while mechanical waves are effectively the result of particles being moved, that is, they require a medium (water molecules for the sea, air molecules for sound, etc.), there is no such material medium in space.

    Maxwell's Equations may describe the behaviour of EM waves, but I am not sure they describe the nature of EM waves.

    Does the Standard Model apply to an X-Ray without mass?? When a wave travels towards us from the earliest times of the universe, do we explain it as a simple matter of a particle travelling without the obstruction of an atmosphere or is the wave interacting with the fabric of the universe at every stage of the way, allowing energy to be moved along and keeping it going?

    If the latter hypothesis is the closest answer, where can I find out more? If anyone has some idea I would appreciate it.

    .o:0|O|0:o.

    P.S. Do not reply if you are high or hyper religious and do not reply if you have a narcissistic need to prove that you are a superior being (if you are feeling a deep seated competitive rage emerging while reading this, then you are the infantile idiot I am talking to right here). I am only interested in understanding this problem, not in social rubbish.


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  3. #2 Re: What do electromagnetic waves "ride on"? 
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    Quote Originally Posted by .o:0|O|0:o.
    Does anyone actually know how EM waves propagate through space?

    They have alternating oscillating electric field and magnetic field components, they vary in frequency/ wave-length and have many curious behavioural characteristics (wave-particle duallity for photons), but while mechanical waves are effectively the result of particles being moved, that is, they require a medium (water molecules for the sea, air molecules for sound, etc.), there is no such material medium in space.

    Maxwell's Equations may describe the behaviour of EM waves, but I am not sure they describe the nature of EM waves.

    Does the Standard Model apply to an X-Ray without mass?? When a wave travels towards us from the earliest times of the universe, do we explain it as a simple matter of a particle travelling without the obstruction of an atmosphere or is the wave interacting with the fabric of the universe at every stage of the way, allowing energy to be moved along and keeping it going?

    If the latter hypothesis is the closest answer, where can I find out more? If anyone has some idea I would appreciate it.

    .o:0|O|0.

    P.S. Do not reply if you are high or hyper religious and do not reply if you have a narcissistic need to prove that you are a superior being (if you are feeling a deep seated competitive rage emerging while reading this, then you are the infantile idiot I am talking too right here). I am only interested in understanding this problem, not in social rubbish.
    Electromagnetic waves are nothing more than a bunch of photons. Photons are particles and no more require a medium through which to propagate than does a baseball.

    Maxwell's equations are a classical description of the behavior of electromagnetic waves, but are not the most fundamental description of electrodynamics. The most fundamental description available is the quantum field theory known as quantum electrodynamics. If you wish to study that subject there are some books available, but you will need to deal with some fairly serious mathematics, mathematics that is beyond the level one expects from the way you posed your question.

    You might look at the links provided in the sticky thread on QED in this forum. They contain lectures by Feynman, a principle architect of QED, for a general audience.

    X-rays are photons and are fully covered by QED.


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  4. #3 Re: What do electromagnetic waves "ride on"? 
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    Thanks for the reply*. I already anticipate any explanation as requiring energy and dedication in order to understand it. Hence, asking for some exact indications in advance so that I may aim my focus more definitely. I am indifferent as to whether photons interact with a "fabric" of the universe or otherwise. After studying Maxwell's Equations I found it didn't satisfy my questions profoundly enough.
    So you believe that QED as presented by Feynman is current and provides very good answers to my question? I have a lot of respect for Feynman, his outlook and honest approach to science.

    [*Though, I find it amusing that you should so eagerly attempt to comment on my mathematical knowledge without any prior information. Not very scientific even if probability is on your side when making such judgements. Ironically, from that sort of comment, I might deduce similar conclusions about you. Fortunately, I am only interested in whether I understand, not whether others understand. If your primitive inner ape feels slighted by my response: see the above post scriptum once again.]

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  5. #4 Re: What do electromagnetic waves "ride on"? 
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    Quote Originally Posted by .o:0|O|0:o.
    [*Though, I find it amusing that you should so eagerly attempt to comment on my mathematical knowledge without any prior information. Not very scientific even if probability is on your side when making such judgements. Ironically, from that sort of comment, I might deduce similar conclusions about you. Fortunately, I am only interested in whether I understand, not whether others understand. If your primitive inner ape feels slighted by my response: see the above post scriptum once again.]

    .o:0|O|0.
    If you had the mathematical background necessary for an in-depth treatment of QED you would not be asking the question. I was trying to pitch the answer at an appropriate level. If you don't like it that is just too damn bad.

    Deduce what you like. The truth is that I have the background and decades of experience to make a pretty informed guess based on what and how people ask technical questions.
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  6. #5  
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    Here's a question that occured to me (I apologise if it's obvious, its 5.27am here and I cant sleep - I have a nasty cold).

    Energy causes spacetime to warp. Will an electromagnetic wave eventually dissapear as it's energy is converted into gravitational waves?

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    Quote Originally Posted by sox
    Here's a question that occured to me (I apologise if it's obvious, its 5.27am here and I cant sleep - I have a nasty cold).

    Energy causes spacetime to warp. Will an electromagnetic wave eventually dissapear as it's energy is converted into gravitational waves?
    I don't think so.

    But to explain it properly I would have to study up on just how an electromagnetic wave figures into the stress-energy tensor of general relativity. I think it goes in in such a way that it does not contribute. (If you were to go yo the BAUT forum and put this question to publius he could probably give you a clear quick explanation)

    In any case so-called "tired light" mechanisms to explain cosmic red shift have been examined and dismissed.

    There are theoretical gravitational structures studied by John Archibald Wheeler, called geons, composed entirely of light, so it is not completely straightforward. But I don't understand the details.

    http://en.wikipedia.org/wiki/Geon_(physics)

    http://arxiv.org/abs/gr-qc/9810045
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  8. #7  
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    P.S. Do not reply if you are high or hyper religious and do not reply if you have a narcissistic need to prove that you are a superior being (if you are feeling a deep seated competitive rage emerging while reading this, then you are the infantile idiot I am talking to right here). I am only interested in understanding this problem, not in social rubbish.
    http://physics.about.com/od/lightoptics/f/photon.htm.

    Although this should help with your other problems; http://hightimes.com/.
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  9. #8  
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    Quote Originally Posted by GiantEvil
    P.S. Do not reply if you are high or hyper religious and do not reply if you have a narcissistic need to prove that you are a superior being (if you are feeling a deep seated competitive rage emerging while reading this, then you are the infantile idiot I am talking to right here). I am only interested in understanding this problem, not in social rubbish.
    http://physics.about.com/od/lightoptics/f/photon.htm.

    Although this should help with your other problems; http://hightimes.com/.

    Thanks. Not very deep, and nice attempt at humour.

    Is there any experimental evidence that the mass of the photon is zero? (That a photon with mass would cause problems for the QED is not evidence).

    .o:0|O|0:o.
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  10. #9  
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    Quote Originally Posted by .o:0|O|0:o.
    Quote Originally Posted by GiantEvil
    P.S. Do not reply if you are high or hyper religious and do not reply if you have a narcissistic need to prove that you are a superior being (if you are feeling a deep seated competitive rage emerging while reading this, then you are the infantile idiot I am talking to right here). I am only interested in understanding this problem, not in social rubbish.
    http://physics.about.com/od/lightoptics/f/photon.htm.

    Although this should help with your other problems; http://hightimes.com/.

    Thanks. Not very deep, and nice attempt at humour.

    Is there any experimental evidence that the mass of the photon is zero? (That a photon with mass would cause problems for the QED is not evidence).

    .o:0|O|0.
    The fact that the speed of light is the same in all reference frames implies that the rest mass is zero.
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  11. #10 What do electromagnetic waves "ride on"? 
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    I can supply what you're after, I have the pertinent answer to your question.
    Although I don't know why, it seems I am already in trouble before even starting
    (this is in fact my debut). To avoid further problems I can only pass the information privately; please e-mail me - regards
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  12. #11 Re: What do electromagnetic waves "ride on"? 
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    Quote Originally Posted by .o:0|O|0:o.
    Does anyone actually know how EM waves propagate through space?
    They propagate just like any other waves. A wave in a solid is said to propagate due to motion of particles, but look deeper and you get down to electromagnetic field interactions in atoms that are "99% empty space". It's similar for an EM wave, only it's in "100% empty space".

    Quote Originally Posted by .o:0|O|0:o.
    They have alternating oscillating electric field and magnetic field components, they vary in frequency/ wave-length and have many curious behavioural characteristics (wave-particle duallity for photons), but while mechanical waves are effectively the result of particles being moved, that is, they require a medium (water molecules for the sea, air molecules for sound, etc.), there is no such material medium in space.
    Actually EM waves don't consist of separate electric and magnetic fields variations, it's just the one field, the electromagnetic field. And think about pacing an oceanic swell wave in a helicopter. It's essentially a pressure pulse. In similar vein an EM wave is a stress-energy pulse in space.

    Quote Originally Posted by .o:0|O|0:o.
    Maxwell's Equations may describe the behaviour of EM waves, but I am not sure they describe the nature of EM waves.
    Here's a couple of interesting papers: http://arxiv.org/abs/0803.2596 and http://arxiv.org/pdf/quant-ph/0604169. I don't quite agree with the dimensional aspect fo the latter, but it gets across the way a photon is a pulse of wavefunction, and that this has a physical reality. I'd say think of the photon as a soliton wave rather than a billiard-ball particle.

    Quote Originally Posted by .o:0|O|0:o.
    Does the Standard Model apply to an X-Ray without mass?
    Yes. Mass is rest mass, light has no mass because it isn't at rest. Here's a paper that's well worth reading: Light is Heavy by van der Mark and 't Hooft. It describes how a massless photon trapped in a mirror-box adds mass to that system. Open the box and the photon escapes, the system loses energy/momentum, and the mass is reduced. This is akin to Einstein's E=mc˛ paper Does the Inertia of a Body Depend upon its Energy Content?.

    Quote Originally Posted by .o:0|O|0:o.
    When a wave travels towards us from the earliest times of the universe, do we explain it as a simple matter of a particle travelling without the obstruction of an atmosphere or is the wave interacting with the fabric of the universe at every stage of the way, allowing energy to be moved along and keeping it going?
    The latter, though "fabric" isn't quite the right word. Space isn't nothing, it does sustain waves and fields, but it isn't a fabric or substance in the usual sense of the word.

    Quote Originally Posted by .o:0|O|0:o.
    If the latter hypothesis is the closest answer, where can I find out more? If anyone has some idea I would appreciate it.
    It all comes back to displacement current. Think about vacuum permittivity ε0 and permeability μ0. These combine as vacuum impedance Z0=√(μ0/ε0), impedance being resistance to alternating current. They also combine as c=√(1/ε0μ0), this expression being akin to the mechanics expression v = √(G/ρ) where G is the shear modulus of elasticity relating to stiffness, and ρ is density. ε0 is like stiffness and μ0 is like density. Take a look at Mordehai Milgrom's New Physics at Low Accelerations (MOND): an Alternative to Dark Matter at http://arxiv.org/abs/0912.2678 and note this line on page 5:

    "We see that the modification of GR entailed by MOND does not enter here by modifying the ‘elasticity’ of spacetime (except perhaps its strength), as is done in f(R) theories and the like."

    I wouldn't say MOND was quite right, but this "strength of space" thing does feel like the best way to describe it. IMHO what's important is that an electromagnetic wave involves an EM field variation. The field can't vary without some form of current. There's no charged particle moving, so it isn't conduction current. Instead it's displacement current, and it's alternating. That's why impedance applies. What's waving in an electromagnetic wave? In a nutshell: space itself.
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  13. #12 Re: What do electromagnetic waves "ride on"? 
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    Quote Originally Posted by Farsight
    Quote Originally Posted by .o:0|O|0:o.
    Does anyone actually know how EM waves propagate through space?
    They propagate just like any other waves. A wave in a solid is said to propagate due to motion of particles, but look deeper and you get down to electromagnetic field interactions in atoms that are "99% empty space". It's similar for an EM wave, only it's in "100% empty space".

    Quote Originally Posted by .o:0|O|0:o.
    They have alternating oscillating electric field and magnetic field components, they vary in frequency/ wave-length and have many curious behavioural characteristics (wave-particle duallity for photons), but while mechanical waves are effectively the result of particles being moved, that is, they require a medium (water molecules for the sea, air molecules for sound, etc.), there is no such material medium in space.
    Actually EM waves don't consist of separate electric and magnetic fields variations, it's just the one field, the electromagnetic field. And think about pacing an oceanic swell wave in a helicopter. It's essentially a pressure pulse. In similar vein an EM wave is a stress-energy pulse in space.

    Quote Originally Posted by .o:0|O|0:o.
    Maxwell's Equations may describe the behaviour of EM waves, but I am not sure they describe the nature of EM waves.
    Here's a couple of interesting papers: http://arxiv.org/abs/0803.2596 and http://arxiv.org/pdf/quant-ph/0604169. I don't quite agree with the dimensional aspect fo the latter, but it gets across the way a photon is a pulse of wavefunction, and that this has a physical reality. I'd say think of the photon as a soliton wave rather than a billiard-ball particle.

    Quote Originally Posted by .o:0|O|0:o.
    Does the Standard Model apply to an X-Ray without mass?
    Yes. Mass is rest mass, light has no mass because it isn't at rest. Here's a paper that's well worth reading: Light is Heavy by van der Mark and 't Hooft. It describes how a massless photon trapped in a mirror-box adds mass to that system. Open the box and the photon escapes, the system loses energy/momentum, and the mass is reduced. This is akin to Einstein's E=mc˛ paper Does the Inertia of a Body Depend upon its Energy Content?.

    Quote Originally Posted by .o:0|O|0:o.
    When a wave travels towards us from the earliest times of the universe, do we explain it as a simple matter of a particle travelling without the obstruction of an atmosphere or is the wave interacting with the fabric of the universe at every stage of the way, allowing energy to be moved along and keeping it going?
    The latter, though "fabric" isn't quite the right word. Space isn't nothing, it does sustain waves and fields, but it isn't a fabric or substance in the usual sense of the word.

    Quote Originally Posted by .o:0|O|0:o.
    If the latter hypothesis is the closest answer, where can I find out more? If anyone has some idea I would appreciate it.
    It all comes back to displacement current. Think about vacuum permittivity ε0 and permeability μ0. These combine as vacuum impedance Z0=√(μ0/ε0), impedance being resistance to alternating current. They also combine as c=√(1/ε0μ0), this expression being akin to the mechanics expression v = √(G/ρ) where G is the shear modulus of elasticity relating to stiffness, and ρ is density. ε0 is like stiffness and μ0 is like density. Take a look at Mordehai Milgrom's New Physics at Low Accelerations (MOND): an Alternative to Dark Matter at http://arxiv.org/abs/0912.2678 and note this line on page 5:

    "We see that the modification of GR entailed by MOND does not enter here by modifying the ‘elasticity’ of spacetime (except perhaps its strength), as is done in f(R) theories and the like."

    I wouldn't say MOND was quite right, but this "strength of space" thing does feel like the best way to describe it. IMHO what's important is that an electromagnetic wave involves an EM field variation. The field can't vary without some form of current. There's no charged particle moving, so it isn't conduction current. Instead it's displacement current, and it's alternating. That's why impedance applies. What's waving in an electromagnetic wave? In a nutshell: space itself.
    A voice of reason. Thanks.
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    A pleasure Doc. It's actually rather difficult to describe this sort of thing in a fashion that can be conceptualized. I imagine the above isn't perfect, but I offer what I can.
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    Very informative Farsight and it gives some credence to how I have been envisaging EM wave propagation as a complete layman. Thanks.

    I have been thinking of EM waves as solitons for a while, but I know it isn't as simple as that or strictly correct. I do what I can also though. :wink:

    I have been trying to think of a way to explain matter as perturbations of the "fabric of space" as well, but I really don't want all the rabble to get involved with their misinformed opinions. I will start a thread in the new hypothesis thread in due time though. I want the thread to progress as a flight of fancy, or more accurately, as an investigation of what is possible given what is known already under certain possibly fictional circumstances. I would very much appreciate the participation of people that really know what they are talking about like you and DrRocket.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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  16. #15  
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    Quote Originally Posted by KALSTER
    I have been trying to think of a way to explain matter as perturbations of the "fabric of space" as well, but I really don't want all the rabble to get involved with their misinformed opinions.
    That is not too far off from yhe idea of elementary particles as bumps in a quantum field, in the spacetime of special relativity. But no one knows how to do that properly in the context of general relativity and curved spacetime.

    I think any meaningful discussion will of necesity be short. Not much is known, and from what I know of attempts at QFT in curved spacetime (baby step towards QFT with GR) there are lots of problems.
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    Quote Originally Posted by KALSTER
    Very informative Farsight and it gives some credence to how I have been envisaging EM wave propagation as a complete layman. Thanks. I have been thinking of EM waves as solitons for a while, but I know it isn't as simple as that or strictly correct. I do what I can also though.
    Thank you too Kalster. I hear all sorts of ideas as to why a photon doesn't dissipate, ranging from space itself acting as a wave guide, "saturation", plane-polarized photons being doubly-circular polarized photons, and a crystalline aspect to space itself. I'm not sure what to think, but I have a hunch it's something to do with the bag model and the fine structure constant. IMHO the bottom line is why do we see that h in E=hf. And IMHO the $64000 question is this: in low-energy proton-antiproton annihilation to gamma photons, where does the strong force go?



    Quote Originally Posted by KALSTER
    I have been trying to think of a way to explain matter as perturbations of the "fabric of space" as well, but I really don't want all the rabble to get involved with their misinformed opinions. I will start a thread in the new hypothesis thread in due time though. I want the thread to progress as a flight of fancy, or more accurately, as an investigation of what is possible given what is known already under certain possibly fictional circumstances. I would very much appreciate the participation of people that really know what they are talking about like you and DrRocket.
    Noted. But have a good look at displacement current. I tend to think of light as a "perturbation in space", a field variation, a wavefunction, a spacewarp, a displacement rippling through space at c. Setting gravity aside, it travels an open linear path. Then have a look at topological quantum field theory and ask yourself this: what sort of path might you get if a displacement travelling at c was somehow travelling through itself?


    Quote Originally Posted by DrRocket
    That is not too far off from the idea of elementary particles as bumps in a quantum field, in the spacetime of special relativity. But no one knows how to do that properly in the context of general relativity and curved spacetime. I think any meaningful discussion will of necesity be short. Not much is known, and from what I know of attempts at QFT in curved spacetime (baby step towards QFT with GR) there are lots of problems.
    I've seen a few draft papers, they're FYEO so I can't divulge. The approach is novel, because the mathematical language of GR is so very different to QFT. Maybe too novel, we'll see, these things take time, and there's always some resistance. But to give you a taste of it, remember how I've been droning on about displacement current? Think about LIGO and gravitational waves:



    Oh I'll spit it out. That stuff I was saying about time is crucial here, because whilst the gravitational field is curved spacetime, the electromagnetic field is curved space. You displace space, so you make the surrounding space curve. It relates to the Aharonov-Bohm effect which was actually predicted by Ehrenberg and Siday in The Refractive Index in Electron Optics and the Principles of Dynamics in 1949. A is at a maximum in the middle of sinusoidal EM waveform where the E/B field variation is zero. So there's your bump:

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  18. #17 Re: What do electromagnetic waves "ride on"? 
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    Quote Originally Posted by .o:0|O|0:o.
    Does anyone actually know how EM waves propagate through space?

    They have alternating oscillating electric field and magnetic field components, they vary in frequency/ wave-length and have many curious behavioural characteristics (wave-particle duallity for photons), but while mechanical waves are effectively the result of particles being moved, that is, they require a medium (water molecules for the sea, air molecules for sound, etc.), there is no such material medium in space.

    Maxwell's Equations may describe the behaviour of EM waves, but I am not sure they describe the nature of EM waves.

    Does the Standard Model apply to an X-Ray without mass?? When a wave travels towards us from the earliest times of the universe, do we explain it as a simple matter of a particle travelling without the obstruction of an atmosphere or is the wave interacting with the fabric of the universe at every stage of the way, allowing energy to be moved along and keeping it going?

    If the latter hypothesis is the closest answer, where can I find out more? If anyone has some idea I would appreciate it.

    .o:0|O|0.

    P.S. Do not reply if you are high or hyper religious and do not reply if you have a narcissistic need to prove that you are a superior being (if you are feeling a deep seated competitive rage emerging while reading this, then you are the infantile idiot I am talking to right here). I am only interested in understanding this problem, not in social rubbish.
    Well, I need to say, I'm not fully sure if I was the infantile idiot who you are talking to now, but I like to lay out my point of view regarding the issue.

    I think you should not search for a carrier medium carrying EM waves. They will not ride something on. Furthermore if we go talking about waves in physics we might talk about an mass which was like a single particle that got in the way of an other very much larger particle.

    It is being hindered to travel by an other object; just like an other particle. On the net there was being a website at www.cessna.com depicting very clearly, to understand this thesis.

    Please chose one of the airplanes and then click on 'Range Maps' to the lower left. Unfortunately the Range Maps site wasn't available now that I type these lines of text. But I try to tell out of my memory.

    An other airplane which you could choose on the Range Maps web site was managed to be shown as to be the center of a sphere, I think.

    The closer you move the airplane towards earth the more you change the assumed sphere this plane still is being the center of. The assumed sphere (the one of which the plane was in the center off ) more and more 'morphs' to a wave. Can you see this? This was because the planet earth was being in the way of the thought sphere the plane was surrounded by (as well as in center ),

    well I had this idea of a particle turning a wave before I got to the cessna.com website, but there you could see how it does look like.

    Steve
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    And IMHO the $64000 question is this: in low-energy proton-antiproton annihilation to gamma photons, where does the strong force go?
    Do you know what the energies of those photons are?

    I'll take a look at your suggestions, thanks. I must prepare you guys in advance though, my understanding is not sophisticated in the least and my ideas are also awash with naivete. While it is fun to think about this stuff from a position of ignorance, ultimately I want my understanding and my ideas to be based in reality. So even if I spout something that will normally let one go "oh no, here we go again", know that my intention is to build towards a scientifically robust concept, if at least superficially.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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    The same as the proton and antiproton energies, 938.272 MeV apiece. See this Fermilab page for something plucked at random from the internet:

    "Consider that one proton-antiproton annihilation both at rest will yield 2 photons (X-rays) with a combined energy of only 1.88 GeV".

    Noted re understanding. I would add that if you don't understand it, it'll be my fault.
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  21. #20  
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    Quote Originally Posted by Farsight
    The same as the proton and antiproton energies, 938.272 MeV apiece.
    As required toconserve energy.

    And the rason that two photons are required is that momentum is also conserved.
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    Quote Originally Posted by Farsight
    The same as the proton and antiproton energies, 938.272 MeV apiece. See this Fermilab page for something plucked at random from the internet:

    "Consider that one proton-antiproton annihilation both at rest will yield 2 photons (X-rays) with a combined energy of only 1.88 GeV".
    Cool. What I wanted to get at, is that, AFAIK, the strong force adds to and is the largest portion of the mass of a proton/neutron.

    I am not sure how to calculate how big a portion of the energy from those photons can be attributed to the strong force, but:

    "The mass of the proton is about eighty times greater than the sum of the rest masses of the quarks that make it up, while the gluons have zero rest mass. The extra energy of the quarks and gluons in a region within a proton, as compared to the energy of the quarks and gluons in the QCD vacuum, accounts for over 98% of the mass. (Wiki)".

    The electron positron annihilation results in the production of two photons of only 511 keV each.
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  23. #22  
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    Quote Originally Posted by KALSTER
    I am not sure how to calculate how big a portion of the energy from those photons can be attributed to the strong force, but:

    "The mass of the proton is about eighty times greater than the sum of the rest masses of the quarks that make it up, while the gluons have zero rest mass. The extra energy of the quarks and gluons in a region within a proton, as compared to the energy of the quarks and gluons in the QCD vacuum, accounts for over 98% of the mass. (Wiki)".
    You answered your own question. Remember, mass and energy are the same thing. E=mc^2
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    Of course.
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    The EM wave is weird; a wave passing us can be seen to be a cyclic transverse magnetic field alternating with a transverse electric field, the energy cycling between these two forms, from the parts in Maxwell's equations that tell us a changing field generates the alternate field. However, the electric and magnetic fields themselves do not move any more than the water moves with the ripples when a wave travels over the sea- the water just oscillates in place. Now for the really weird bit - not only are the electric and magnetic fields not travelling from our viewpoint, they are not travelling from any frame of observer reference. That is, the fluctuating fields, although not moving, have no absolute location. That means that location is meaningless to the electromagnetic disturbances of an EM wave. One of the wonders of Relativity.

    The other crucial difference between EM waves and (say) sound waves, is that we - and all matter - are built out of the medium through which they travel. As such, we have no way of peeking into a level more fundamental than the one we are at. The internal nature of spacetime seems inaccessible to a creature built out of spacetime. One can theorise, with strings or whatever, but there is no way of proving anything without such access.
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    That means that location is meaningless to the electromagnetic disturbances of an EM wave. One of the wonders of Relativity.
    Is this due to the frame of reference being taken as from the phonon itself, which derives this peculiarity because of it propagating at C (from the photon's point of view, it is essentially everywhere at once)?
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  27. #26  
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    Quote Originally Posted by muppet
    The EM wave is weird; a wave passing us can be seen to be a cyclic transverse magnetic field alternating with a transverse electric field, the energy cycling between these two forms, from the parts in Maxwell's equations that tell us a changing field generates the alternate field. However, the electric and magnetic fields themselves do not move any more than the water moves with the ripples when a wave travels over the sea- the water just oscillates in place. Now for the really weird bit - not only are the electric and magnetic fields not travelling from our viewpoint, they are not travelling from any frame of observer reference. That is, the fluctuating fields, although not moving, have no absolute location. That means that location is meaningless to the electromagnetic disturbances of an EM wave. One of the wonders of Relativity.

    The other crucial difference between EM waves and (say) sound waves, is that we - and all matter - are built out of the medium through which they travel. As such, we have no way of peeking into a level more fundamental than the one we are at. The internal nature of spacetime seems inaccessible to a creature built out of spacetime. One can theorise, with strings or whatever, but there is no way of proving anything without such access.
    What have you been smoking ?
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    What have you been smoking ?
    Is this another QM argument for the existence of photons and non-existence of electromagnetism?


    EM and QM are very different models of the universe, each with their own shortcomings. Neither is the universe, only an imperfect model of it. Arguments based in one model of the universe cannot be used to invalidate another model of the universe with different premises. Photons are essential to the theory of QM, but have no place in EM; this does not invalidate EM. In EM, energy level transitions merely extract a certain amount of energy from the EM wave.

    Don't mix and match your models - the question as asked lies in the EM domain.
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    Quote Originally Posted by muppet
    Is this another QM argument for the existence of photons and non-existence of electromagnetism?
    You can't have one without the other. Electromagnetic waves are just a bunch of photons.

    Classically, you can describe electromagnetic waves with no need for photons, which is precisely what is done using Maxwell's equations. But that has little to do with your fanciful description.
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