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Photons - the smallest building block?

  1. Apr 21, 2008 #1
    Forgive my ignorance if I'm missing something obvious; although I try to stay informed my interest in physics is rather casual. However, I do like to think and speculate about such things based on the knowledge I already have.

    So with this in mind, I thought I'd just get some feedback on some of these thoughts. What I'd like to know is if there is anything that dismisses the possibility that everything, quarks, electrons, etc., could be made up of photons of varying wavelengths, that when certain conditions are met photons will group together to form what we know as 'mass'.

    Taking this further, I'd like to know if it is possible that even the fundamental forces could actually be photons; perhaps of such wavelength and properties that we cannot ( yet ) perceive of them?

    Any thoughts on this? Is there anything that contradicts this completely?
  2. jcsd
  3. Apr 21, 2008 #2
    Well, these "properties we cannot ( yet ) perceive" would mean that the fundamental particles aren't photons as we know them.

    Physicists tend to like models which simplify things, and having a zoo of particles be different excitations of a single particle is appealing. However, we know that particles themselves aren't fundamental and that quantum field are the fundamental entities. Particles are only seen because we build particle detectors =)

    This may not be up your alley, but two places where different particles emerge from a single entity is a) string theory, as vibrational modes of the string, and b) supergravity, as components of a superfield.

    But these are only theories. It's up to experiments to decide.
  4. Apr 21, 2008 #3
    Since photons travel at the speed of light and mass does not, it is not clear how the photons could be given inertia. Also, where would charge come from, since photons have no charge?

    You might be able to classically model a binary photon "system" orbiting around one another like a binary star, but I believe the distances would be much smaller than a Planck Length and therefore the laws of gravity would break down.

    Also, one of the fundamental forces is electromagnetism, whose carrier is the VIRTUAL photon, but it's not a real photon. It's not like we detect photons emanating from electrons and call that charge. So there's no reason to think that any of the forces, let alone all of them, are really just photons being exchanged.
  5. Apr 21, 2008 #4
    But it was my understanding that when, for instance, an electron and a positron collided, they would actually "transform" into photons. I suppose then that the reverse is also possible? Meaning something without a charge, photons, could be made into something with a charge?

    As for the 'why doesn't mass then travel at light speed' thing, couldn't that simply have to do with the photons being tied to each other? Let's say a stationary particle consisted of 10 photons. 5 of those had momentum in direction x, the other 5 had momentum in direction y - exact opposite of direction x. So you add another photon with momentum in direction x and the whole thing starts moving in that direction. You add another and it moves even faster. Add more and more and it goes faster and faster in that direction; however, you will never quite reach c because there will always be those 5 other photons with momentum in the other direction.
  6. Apr 21, 2008 #5


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    A major, major problem with photons is that they have no electric charge. Also there's no way any number of photons can make a spin 1/2 electron.
    Interesting question? Of course.
    Reilly Atkinson
  7. Apr 21, 2008 #6


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    Pair production, i.e. where photons become particle-antiparticle pairs, does not necessarily mean that one is made up of the other. All that says is that one can be converted into the other. A photon alone cannot turn into an electron because of conservation laws. So already you can see that one simply cannot say that an electron is made up of photons.

  8. Apr 22, 2008 #7
    well, it is convenient to say that massive particles are just nature's way of packaging energy in greater quantities, and the basic equation E=mc^2 certainly indicates that any mass can be equally correctly designated as its equivalent amount of energy (photons). that said, photons alone do not account for the other properties we recognize in particles which have mass, such as charge. it is not clear where these additional properties arise, but the comment above seems correct to me, that it is actually fields, rather than particles, which are the fundamental entity. now, if we could just figure out what a field is...
  9. Apr 22, 2008 #8
    It's conceivable photons of constructively interfering wavelengths, properties, or some other ad hoc mechanism would allow for photon binding. Intuitively signs point to the photon as a fundamental constituent of nature. I suppose all we can do is wait for experimental data.

    As I understand immediately proceeding the big bang photons 'decayed' into elementary particles. I also understand throwing sufficient energy into the vacuum will generate particles.
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