- #36
greswd
- 764
- 20
oh yeah. there is no incoming photon that exists which can collide with the electron or something.stevendaryl said:This is easiest to see in the rest frame of the particle. Then initially, the momentum is zero. Initially, the energy is [itex]mc^2[/itex]. After it emits a photon, the energy of the particle must still be at least [itex]mc^2[/itex] (because that's the lowest possible energy of the particle), which means that the energy of the photon has to zero (or negative!) to get energy to balance.