jdavel
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Antonio Lao said, 'But it is also true that magnetic field can exist only if there is some charges moving (current density). But in "empty" space, there is no charge and no current yet there is electromagnetic field. Since there must be some sort of "charge" or "current" in vacuum in order for the EM field to exist, these "charge" and "current" must be some kind of properties of space itself. For purposes of distinction, we can call them "space charge" and "space current." '
Nonsense! The laws of classical electricity and magnetism don't require there to be charges or currents wherever there is a field. That's the whole idea of the field; it exists in space even where there is no charge. The EM laws just say that if there is a field somewhere, there must be charges somewhere.
Nonsense! The laws of classical electricity and magnetism don't require there to be charges or currents wherever there is a field. That's the whole idea of the field; it exists in space even where there is no charge. The EM laws just say that if there is a field somewhere, there must be charges somewhere.