A simulation of the motion of stars, measured by the analysis of emitted photons.

The interactions of the subjects of radiative transfer and physical optics can result in shifts in the wavelength and frequency of electromagnetic radiation. In such cases, the shifts correspond to a physical energy transfer to matter or other photons rather than being by a transformation between reference frames. Such shifts can be from such physical phenomena as coherence effects or the scattering of electromagnetic radiation whether from charged elementary particles, from particulates, or from fluctuations of the index of refraction in a dielectric medium as occurs in the radio phenomenon of radio whistlers.

Larger panel sizes are increasingly rare. Larger ranges of color are increasingly rare. Slow movement takes place over time. Horizontal rotation is less common. Entropy is high.