Post #231923 2.54K Sep 10, 2026, 02:43 UTC Show HN: What if the speed of light was 5 km/h?Article, Comments Dmitrybrant Relativity Park: Walking Speed of Light Special relativity simulator in which light crawls along at a human speed, so Lorentz contraction, aberration and Doppler shift happen at walking pace. 🌭 7