It's the maximum speed through space and time. The speed of light through time is just 1s/s. Einstein says space and time are equivalent, so as your velocity th

It's the maximum speed through space and time. The speed of light through time is just 1s/s. Einstein says space and time are equivalent, so as your velocity through space approaches c, your velocity through time approaches zero and vice-versa. The photon has zero velocity through time because its velocity through space is c. In its reference frame, no time passes between creation and destruction, but from all other reference frames it appears to be moving through space in discrete time but with high velocity.