When I was a kid I’d notice when my dad was trimming a motor in the garage by the mess it made with the RF modulator of our Amiga 500, my stereo, and about everything else electric my brother and had in our room one floor above. It was a brief interruption, but quite significant.
Today we’re enveloped in radio waves, and while the spectrum is quite carefully divided, noise sources can of course not be controlled as closely. They can also wreck havoc with reception and interfere in operations.
There’s an interesting article over at IEEE Spectrum covering this in more detail, and arguing that we need to start studying radio-frequency noise:
the RF noise problem is increasing. Although most devices pollute less than their predecessors, we have far more of those devices. Other sources, such as the power grid, are expanding as wind farms and solar households connect to it.
It is an interesting problem. As our technical infrastructure becomes more complex we can expect more sources of noise to result from faulty devices, or as by products of physical processes. Their magnitute may dwarf compare to mega-sources such as the sun, but by their nature they are hard to find and may appear as random faults to us.