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Binding force applicable only to photons?

  1. Sep 3, 2012 #1
    Two Questions about fundamental forces:

    1. Gravity is attractive, Electromagnetics is attractive and repulsive, Strong nuclear is attractive only (?) ... Is the weak nuclear force repulsive only ? Wikipedia is _vague_ on this. Also, I'm remembering that gravity increase with the square of the distance, electromagnetics likewise, but strong and weak increase with higher exponents. Is this correct?

    2. With E=Mc^2, it follows that mass is condensed photons. QUESTION: If there are binding (attractive) forces active over VERY small distances (following some inverse-Nth law), then the only 'particles' small enough to be bound together are photons. Is this an existing idea that has a popular name, is this obviously wrong for some reason, or is it a novel concept? I'm just some guy, I have no right to claim novel thought in this realm, it strikes me this has probably been thought of before.
  2. jcsd
  3. Sep 3, 2012 #2


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    The weak force is better understood as an interaction, not a classical force. It doesn't push or pull objects, it allows them to interact and do things like decay into certain other particles. The fundamental forces are usually understood as interactions when we get into Quantum Mechanics, as the concept of force in the classical sense, IE a push or pull, does NOT apply. Interactions allow objects to cause changes upon other objects.
    Edit: The end result of say, the electromagnetic interaction between two protons, is the same in both classical physics and QM, it's just that QM has different math that doesn't allow us to use the classical force equation.

    Mass is NOT condensed photons. Photons are the quantized interaction of the electromagnetic field. Put simply, an EM wave passes over something and transfers energy to that object in small "chunks". We label these chunks as photons. Photons have energy which can be transferred to matter, such as when a photon is absorbed and turned into heat, and even be turned into other particles that do have rest mass such as pair production of an electron-positron pair.
  4. Sep 3, 2012 #3
    The strong force can be both attractive and repulsive, depending on the particles involved and the distance between them.

    As Drakkith said, the weak force isn't really a force in the classical sense.

    First, the gravitational force and electromagnetic force *decrease* with the square of the distance from the object.

    The strong force essentially has a maximum range of about 10^-15 meters, beyond which it falls off exponentially. The weak force essentially has a maximum range of 2.5*10^-18 meters, beyond which it falls off exponentially.


    Photons aren't really smaller than other particles. All the fundamental particles in the standard model are point particles. [Note that protons and neutrons are not point particles: they are really composed of several (pointlike) quarks orbiting each other, and so have a finite size]

    It sounds sort of like a geon. Geons, if they're possible, would be "particles" made of electromagnetic or gravitational waves and held together by gravity.
  5. Sep 4, 2012 #4
    Thank you both for your informative replies. I've not had any quantum mechanics classes. My wife and I have been quite impressed that the pervasive growth of internet communications tech has led to the ability to ask serious questions of learned people with minimal overhead costs. The fact that there are people "out there" who are nice enough, and knowledgeable enough, to reply to novice questions - this is a wonderful thing. In a quasi-religious sense, it restores/adds to my faith in humanity. Thank you again.
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