Radium wrote:
"I have a very weird question about electromagnetic radiation, carriers,
and modulators."

It makes no difference which signal you call the modulating signal and
which you call the carrier. Modulation is simply mixing the two together
at a nonlinear point to create new frequencies along with the originals.

The same modulation products are produced by 20 Hz on a 20 KHz carrier
or 20 KHz on a 20 Hz carrier.

The nonlinear point may be a single diode, a diode bridge, or a
high-level plate modulator. The signals out can be the same except for
amplitudes.

I think Ian Jackson has also given a correct answer that is more
complete though less simple.

Best regards, Richard Harrison, KB5WZI