Photon can be emitted by an electron's changing of its orbit. As we know. photon always travels at speed c, never less. That means, a phone would acquire its speed c (relative to the electron/atom) instantaneously (i.e., in 0 elapse of time). What physical force could have made such a push? On the other hand, if we view light just as EM propagation instead of particles, then such question is moot, there would need to be no push, but some sort of media (e.g., vacuum) to allow the wave to propagate at that speed. Thus, if we view light as "beams of particles", what's the explanation of photon's "apparent" infinite acceleration?