|Date: Wed, 9 Jan 2002 18:38:22
Reply is for your benefit only.
Cute comments are not science. No further comment is necessary. For your benefit, we will give him a bit to think about on charge as energy.
In physics, one is perfectly free to choose the fundamental units he wishes to use for his physics model. Indeed, there already are already perfectly valid physics models using only one fundamental unit, and they are well-known and actually used in physics. For those in classical EM and electrical engineering, simply check Jackson, Classical Electrodynamics, Third Edition, who also confirms it.
E.g., suppose we build a physics model using only the fundamental unit "joule". Then all other entities become energy and functions of energy. We have no problem, after the nuclear age, with mass as energy -- the old E = m (c-squared). It gets a bit dicier to think of time as energy, but so it is. And so is length.
And so is charge. Certainly we can model it in that fashion, simply by changing to the model indicated. So one is not justified to just snippily conclude that "charge is not energy". There are no absolute statements in physics; there are only the absolute predictions, assumptions, or findings of a particular model. The same remarks were once made about mass. Models change. And so does physics.
Now ask your friend to explain to you in his model, how a charge (which he believes is not energy) continuously pours out EM energy in all directions in 3-space, without any input of EM energy in 3-space. Easy to prove it. Simply produce a charge at a point in the lab. Its fields and potentials and their energy will reach one light-second distance in any direction in space, one second later. One year later, those same fields and potentials will have reached a surface on out beyond the solar system, at one-light year radius away. And they're still traveling outward at the speed of light, while all the originally detected new field and potential values at lesser radii are still there and being continuously maintained. In short, that is a continuous EM flow. Every charge in the original matter of the universe has been pouring out EM energy, continuously, in this fashion for some 14 billion years.
So by simply paying once to produce that one little charge (e.g., to lift it from the Dirac sea will require only a certain amount of one-time input energy), you have now caused a change in the EM energy density in all of a vast volume of surrounding space that is a lightyear in radius, and the energy flow is still ongoing from the charge. From whence is coming this steady outpouring of EM energy from the charge, outward from the charge in all directions in 3-space?
Either this problem has an explanation of where an equal input of EM energy is coming from, or else we have falsified the entire conservation of energy law by a very simple experiment. It only takes one white crow to prove that not all crows are black. U(1) electrodynamics has not been forthcoming with the explanation.
Have your friend try to explain the source of that enormous amount of output energy in the classical U(1) EM model. It's called the unresolved problem of the source charge, or the problem of the source charge and its association with its fields that it creates, and all their energy that it also produces. Sen (and others) calls it the most difficult problem in electrodynamics, both quantal and classical. We have at least proposed a solution consistent with higher group symmetry electrodynamics, quantum field theory, and particle physics.
But please do not pass along to me any other such cute comments. I simply have no time for such.