GoKawiilInteractive simulation lets users experience relativity with light speed set at 5 km/h
A new browser-based demo, shared on Hacker News, simulates a park environment where light travels at only 5 kilometers per hour instead of its real-world speed. As users move through the space, they can observe relativistic effects like length contraction, time dilation, and the Doppler shift, all normally imperceptible at everyday speeds.