A thought experiment. Imagine you launch a spaceship from a space station that is fixed at a certain location (to eliminate the factor of Earth's orbit) and track its course, by powerful telescope, as it moves away from you to a distance of one light year. Let's say the journey takes ten years. At the point where the spaceship is one light year from you, the light which reflects from it to your telescope takes one year to reach you. This suggests that it would take 11 years to track the 10 year journey. This is the question: If you are observing the spaceship consistently, how does the extra year squeeze in? Does the spaceship appear to slow down? Does it flicker out of sight and then reappear as your perception catches up to the relative position of the object? I find it helpful to introduce a periodic element which can help track the motion of the spaceship. Let's say it has flaps which open and close periodically, in harmony with a defined distance traveled. Over the course of our 11 year observation, would the duration of each flap cycle increase, relative to the spaceship's distance? What if the ship stopped at its one light year destination?--Would the flaps suddenly speed up again? Don't know the answer. Perhaps it is explained in terms of relativity. Can anyone explain it to me?