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marcus
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You are cordially welcome. And thanks to you for the discussion. It's very analogous I think to peoples' preferences for hbar versus h. In advance physics books you typically see hbar. So I can think, if I see a person calculating with h that he is "really" using
2 pi hbar. You can define h = 2 pi hbar.
It is useless to argue. they are really the same constant just surrounded by different words and a different human narrative.
In the case of kc if I see you use epsilonought in a calculation, I just say that you are "really" using 1/(4 pi kc)
Because in my world that is how epsilonought is defined. It simply equals 1 over 4pi times the basic EM constant. It is essentially the same constant but you decorate it with different words and tell a different story about it.
For me, the story with kc is about the relation of charge force and distance ANALOGOUS TO THE STORY WITH NEWTON G. Newton G simply tells me the force between two unit masses placed a distance apart. Coulomb k simply tells me the force between two unit CHARGES placed a distance apart.
I can tell the story of either G or kc without blathering about "space" being a "material" with certain "properties". All there is is charge and geometry (measuring distancees). Or in the case of G there is mass and geometry.
You probably know that in physics books past a certain point they don't necessarily use SI units. SI units are constructed in a peculiar way that grew out of some historical compromises. As an engineer you have to talk to other engineers and you do not have much freedom of units so you are stuck with SI and there is a certain way of thinking that goes with that. It would be a bad idea to try to get out of that way of thinking.
SI is periodically revised by committees in Paris and votes at international conferences backed by the legal force of international treaties. In present SI , CURRENT is based on force between parallel wires a certain distance apart and then charge is defined based on current. Or that was how when last I looked.
To me, the force between parallel wires is a relativistic effect that can be explained given the force between static charges. You transform taking into account relative motion and the magnetic effect falls out. So the basic fact is not parallel wires, the basic fact is like charges repel. Magnetism is a side-effect of the charge law that you get when charges move.
So SI is based on a funny way of thinking, at the very outset. But that's fine. It is all logical on its own terms. And I think eventually it will be reformed and the electron charge will be the basis of definition for electric units. We just need to wait patiently for the slow wheels of international committeehood to turn.
What I'm doing is sketching my attitude for you. You have your own way of thinking and there is no reason we should agree at the level of what we think is fundamental.
I don't believe there is an absolute "space" or that it is a material. Different observers slice spacetime differently. For me the basic venue of reality is not space but geometry---the measurements we make of distances and time durations. The speed of light is a feature of geometry, a fundamental geometric constant that relates the measurements of space and time (and also other stuff).
So for me the speed of light is not a property of some substance called "space". It is not something one measures but something one measures with.
I was pleased back in the 1980s when SI was changed to make it impossible to measure the speed of light. You may recall they redefined the meter so that the speed of light in vacuum had to besuch and such per second, by definition, and could not be measured. That seemed like progress. I suppose the same thing could happen to the elementary charge. We'll see.
2 pi hbar. You can define h = 2 pi hbar.
It is useless to argue. they are really the same constant just surrounded by different words and a different human narrative.
In the case of kc if I see you use epsilonought in a calculation, I just say that you are "really" using 1/(4 pi kc)
Because in my world that is how epsilonought is defined. It simply equals 1 over 4pi times the basic EM constant. It is essentially the same constant but you decorate it with different words and tell a different story about it.
For me, the story with kc is about the relation of charge force and distance ANALOGOUS TO THE STORY WITH NEWTON G. Newton G simply tells me the force between two unit masses placed a distance apart. Coulomb k simply tells me the force between two unit CHARGES placed a distance apart.
I can tell the story of either G or kc without blathering about "space" being a "material" with certain "properties". All there is is charge and geometry (measuring distancees). Or in the case of G there is mass and geometry.
You probably know that in physics books past a certain point they don't necessarily use SI units. SI units are constructed in a peculiar way that grew out of some historical compromises. As an engineer you have to talk to other engineers and you do not have much freedom of units so you are stuck with SI and there is a certain way of thinking that goes with that. It would be a bad idea to try to get out of that way of thinking.
SI is periodically revised by committees in Paris and votes at international conferences backed by the legal force of international treaties. In present SI , CURRENT is based on force between parallel wires a certain distance apart and then charge is defined based on current. Or that was how when last I looked.
To me, the force between parallel wires is a relativistic effect that can be explained given the force between static charges. You transform taking into account relative motion and the magnetic effect falls out. So the basic fact is not parallel wires, the basic fact is like charges repel. Magnetism is a side-effect of the charge law that you get when charges move.
So SI is based on a funny way of thinking, at the very outset. But that's fine. It is all logical on its own terms. And I think eventually it will be reformed and the electron charge will be the basis of definition for electric units. We just need to wait patiently for the slow wheels of international committeehood to turn.
What I'm doing is sketching my attitude for you. You have your own way of thinking and there is no reason we should agree at the level of what we think is fundamental.
I don't believe there is an absolute "space" or that it is a material. Different observers slice spacetime differently. For me the basic venue of reality is not space but geometry---the measurements we make of distances and time durations. The speed of light is a feature of geometry, a fundamental geometric constant that relates the measurements of space and time (and also other stuff).
So for me the speed of light is not a property of some substance called "space". It is not something one measures but something one measures with.
I was pleased back in the 1980s when SI was changed to make it impossible to measure the speed of light. You may recall they redefined the meter so that the speed of light in vacuum had to besuch and such per second, by definition, and could not be measured. That seemed like progress. I suppose the same thing could happen to the elementary charge. We'll see.
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