A photon is the unit of visible light of radiant energy. The possibility of a photon was first considered by Albert Einstein in 1905 as a measurable particulate of the spectrum of light (although it was not named as such until 1926, by Gilbert Lewis). The constant c in referring to the speed of light, is synonymous with the speed at which a photon travels.
The holographic technology maintained by the Xyrillians utilized resequenced photons. (ENT: "Unexpected")