Do light photons, of whatever frequency, emanate only from atoms, or can they sponaneously appear from, literally, nothing? If the former, does the atom have to be "complete", ie. with electrons dancing in attendance, or is the nucleous alone able to produce light photons. If so, is it also the case that individual protons and neutrons, (when suitably excited), are able to produce light photons? Separately, if we were able to approach a light source at, (say), 90% of light speed, would this motion effectively increase the frequency of the light waves such that visible light would appear as ultra-violet, or perhaps x-rays, or even as gamma rays. Also, the reverse. Could gamma rays be effectively lengthened to appear as x-rays, uv. or visible light if we were to recede from a light source? Or does nothing alter regardless of rate of approach or recession?