The impedance of free space is ~120π, or about 377 Ohms.
- What does that mean?
- Does nature oppose the propagation of light?
- If it does, would we even see star light?
- Or is this a fee that, once paid, admits to a photon the right to propagate until it collides with something else?
It turns out that the "impedance" of free space is really just a ratio of strengths.
It is the ratio of the electric field strength, to the magnetic field strength.
Its numerical values are just an artifact of the definition of the ampere and the meter.
It might be interesting to work backwards and say that the impedance of free space is one and see how that could lead to a useful set of units for Maxwell's equations.
