If a human-carrying craft could be devised that could travel at the speed of light indefinitely, and since for the occupants aboard no passage of time is perceived, then would not the occupants be able to travel for an infinite amount of time?
In another thread I suggested that the speed of light is the speed of time. A way I can describe what I mean is to consider that we are in a "wind" moving at the speed of light. If stationary, we "feel" the wind, and we age and everything around us ages as well. But if we are moving "with" the wind (of time), moving at the speed of light, we do not "feel" the wind, and it doesn't affect us, i.e., we do not "age" relative to reference points not moving at the speed of light.
Given that time is a dimension, travelling at the speed of light makes it possible to "move around" in that dimension. Unless we are moving at the speed of light, we cannot "move" in time as we move in three-dimensions. We are "in" the fourth dimension, time, but we can only "flow" along with it ... unless ... we are moving at the speed of light. Moving at the speed of light seems to be the gateway to our moving in the dimension of time. If we could travel at the speed of light indefinitely, it seems we could be called "immortal."
Now, I know that everything is not always as it seems....