Why This Matters
An interactive browser demo drops the speed of light to walking pace, letting anyone experience relativistic effects—length contraction, time dilation, Terrell rotation, and Doppler shifting—by simply moving around a virtual park. It turns abstract physics into something intuitive and visual, a strong example of the web as an educational medium.
Key Takeaways
- A Show HN project simulates a world where light travels at 5 km/h, making relativity perceptible at human speeds.
- It renders multiple effects at once: length contraction, time dilation, Terrell rotation, and blueshift/redshift depending on direction of motion.
- Demonstrates how interactive, real-time browser graphics can teach concepts that are hard to convey with text or equations.
Light is slow here
In this park, the speed of light is 5 kilometers per hour — a brisk walk. Just like in the real world, the speed of light is not attainable, only approachable asymptotically. The more you speed up, the more relativistic effects will become apparent: length contraction, time dilation, Terrell rotation, etc. The Doppler effect of light also becomes apparent, with objects in front of you blueshifted, objects behind you redshifted, and transverse Doppler effects visible on objects in motion.
Click to look around
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