Relativity Lite

(a) (b) H = c τ d = c t r = v t intermediate (c) intermediate r = v t d = c t H = c τ (d) Figure 1. (a) An accelerating spacecraft moves forward one unit in one second, from the bottom to the middle picture, and three more units forward in the next second, top. A light beam shining in a window hits the far wall below where it entered. (b) Because the ship moves three more units forward in the next second than it did in the first, light entering an accelerating spacecraft will seem to bend as it travels from a window to where it hits the far wall. (c) The curved path shown in detail. Also shown is a dotted path for light traveling from the lower to the upper part of a spacecraft traveling at some constant, intermediate velocity. The accelerated curve is seen to be even longer than the hypotenuse that gives time dilation in special relativity. (d) If the acceleration is extreme, these two curves will be indistinguishable and very long, giving extreme time dilation in either case.