Show HN: What if the speed of light was 5 km/h?
Points and comments are a snapshot, not live.
A WebGL simulator lets you experience special relativity with light speed set to 5 km/h.
Relativity Park by Dmitry Brant is an interactive WebGL 2 simulator that reduces the speed of light to 5 km/h so relativistic effects become observable on human scales. Users accelerate with WASD keys, look around with the mouse, and toggle effects: light-travel delay, aberration and contraction, Doppler color shifting, and relativistic beaming. A Ferris wheel, carousel, and shuttle move at 75% of c to demonstrate length contraction, Terrell rotation, and time dilation. The simulator also shows world clocks ticking at different rates depending on your velocity.
What commenters are saying
Commenters praised the simulator and noted similar projects: MIT Game Lab's "A Slower Speed of Light" (2012) and "Velocity Raptor" (a free game with the same concept). One commenter warned that the common slogan "we all travel through time at the speed of light" is misleading because speed through time is a dimensionless ratio, not a velocity with units. Another pointed out that in the real world, such a change to c would alter fundamental constants like the meter and kilogram.