[dleviwing]

Socratus;
The mass of a photon is called “Relative Mass” as is the mass increase of a moving object or particle. The equation refers to the conversion of “REST MASS” to energy. A photon DOES NOT have “Rest Mass”. All the books that just say “Mass” are referring to “Rest Mass” values. Older text and Einstein’s original works did not distinguish a difference in the two until 1925.

BTW: QT is classical once you remove the bull.