If a guy gets on a rocket that travels at the speed of light for a finite period of time (in relation to other observers not moving at C) the guy in the rocket experiences no passage of time. In this scenario his leaving and arrival of the rocket happens at the same time in his frame, correct? Yet an observer watching this happen, sees the guy get on the rocket at point A, some time passes, and he gets off at point B? His progress has a past and this establishes an arrow of time for him from the observer's viewpoint. Is that correct? And if this is so, which way does the arrow of time point for the guy in the rocket? Aren't both the point of origin and destination equally plausible as either? That point A where he departed and point B where he ended his journey are one and the same and can be swapped around? In a possible real version of this problem, if a photon is exchanged between two particles (electromagnetic or strong force carrier photon for example), are two photons exchanged, one from particle A to particle B and one from particle B to particle A? or, is one photon exchanged that satisfies both particle A and B that they have both sent and received a separate force carrier photon (that is one photon between them, that appears to be both arriving and departing both particles simultaneously)? Or is it simply one photon moving from one particle to the other with no reciprocal exchange? Or is it the only other option I can think of, that one photon is sent out from one of the particles, it is received by the other particle and then it sends out a photon in exchange after it receives one.