Hi everybody, I've made another relativity visualization. This time it's about the aging twins, since this is one of the most frequent newbie questions: http://www.adamtoons.de/physics/twins.swf (needs flash plugin: http://www.adobe.com/products/flashplayer/) Besides the common Minkowski diagram it features an Epstein diagram with proper time as the temporal dimension. In that diagram you can directly see the current age difference between the twins. What is also visualized is how the twins see each other during their separation due to signal delay. The paths of the light signals between can also be displayed in both space time diagrams. The inertial frame of reference of the observer can be chosen arbitrary, or set to one of the three interesting cases: - twin A (stays at home) - twin B (leaves earth) - twin B (returns to earth) Comments and ideas are welcome.