Thank you, I had forgotten that the electrons would have mass and thus be unable to move at the speed of light. Also I do understand relativistic velocity addition (something like (v1+v2)/c or something), but thank you for explaining it (I like that this forum is friendly to people who aren't...
Let me set up a hypothetical situation. Say we have a photon traveling through space at c. There is also a singular point behind this photon emitting a magnetic field that the photon is traveling through. Whilst in this field the photon splits into an e+ and e- for an infinitesimally small...