As we know through experiment, the magnetic force around a current carrying wire always points in the same direction given the direction of current, and this direction is described with the ‘right hand rule.’ What is it about the universe that has this ‘preference’ for this, and only this, direction?
Or from a mathematics perspective, why are our electromagnetic vector coordinates the way they are, and not the other way around? It seems the direction of fields is axiomatic to the equations, and something we tack on at the end after calculating magnitudes. For instance, “we just used ampere’s law to calculate the force at this distance from the wire, now to know the direction, let’s use the right hand rule.” Nowhere in the math does it say that the direction is a necessity.
It seems to just be an observed fact, and we have to include this fact in our equations. But this fact is not derived from the equations. For context, I understand that the electromagnetic equations can be solved with either a right or left convention. My question does not pertain to this convention, but the underlying nature of the universe and its ‘preference’ to follow the same direction every time given a direction of current. If it’s said the angular momentum of the vector causes this direction, then still it remains why this direction and not the other?
It all seems so asymmetric and arbitrary.
In: Physics
When we discovered magnetic fields, we decided that magnetic field lines point north to south. It was an arbitrary decision, but we made it.
We also arbitrarily decided that current was the flow of positive charges. We then discovered the electron and realized it came from the negative terminal, so by the rules we had defined, it must have a negative charge.
The electric and magnetic fields always interacted in the same way even before we defined it. Even if you say magnetic field lines run from south to north, you just but a negative sign on all of our math and it works out the same. We just picked one way to stick with so everyone is on the same system.
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