Thank you. I was always wandering why such an obvious concept is hidden so deep in the theory. I think relativity should be taught "backwards": proper velocity first, THEN time dilation and so on.
Is it correct that the time it takes to travel a distance from the point of view of the traveler (measured by their clock) is the same as it is in classical mechanics?
I.e. if you start accelerating at a constant rate, at some point you will go "faster than light" if you define speed as...