> A disturbance of the field at a point only affects the value of the field in the immediate spacetime surroundings, just like a water wave. Ok, I see that's l

> A disturbance of the field at a point only affects the value of the field in the immediate spacetime surroundings, just like a water wave. Ok, I see that's local (though not mechanical, as you say). I think a magnetic field (as from a magnet, not a wave) is not local though? So, the transmissiin of modulation is "local", but the field itself is "at a distance"?