What if the speed of light was 5 km/h?
Get picks like this daily. Today's launch numbers, the top launches, AI and tech news, and a daily opportunity pick, straight to your inbox.
Want to reach these readers? Sponsor an issue.
I've always wanted to make a visualization where the speed of light was scaled down to human speeds, so that we could intuit relativistic effects with everyday objects. Here is the first version of it!
HN · launched Sep 10, 2026 · 626 upvotes (top 1%) · 0 views
Niche: interactive 3d web simulations · 157 launches, 9 in the last 7 days ▼ -47% · Explore this niche →
Category and tags
- Education
- B2C
- Not AI
- Hobby / open-source project
Visit website ↗ Source listing ↗
More like this: all 157 launches in interactive 3d web simulations →
Could you build this?
Partial Creating a standard Three.js or WebGL scene is simple, but accurately implementing physical relativistic shaders (Lorentz boosts, Terrell rotation, relativistic aberration, Doppler shifts, and beaming) requires specialized mathematical and graphics physics knowledge.
What it would actually take: The application relies on custom WebGL/WebGPU GLSL vertex and fragment shaders that apply Lorentz transformation tensors per vertex and compute relativistic Doppler/radiance shifts per fragment. It requires precise mathematical modeling of four-vectors and retarded light-travel times rather than standard rasterization. Doing this smoothly at 60fps in the browser requires expertise in relativistic physics and shader optimization.
Discussion
20 comments analyzed.
Competitors mentioned: A Slower Speed of Light (2012, MIT Game Lab)
Concerns raised: Doesn't work on mobile - no movement controls or predictable camera, Mouse icon disappears after visiting, Physics assumptions unrealistic - reduced c would create black holes and change atomic structure, Latency from distant locations much worse than 300ms estimate, Controls feel inverted - W goes backward instead of forward like FPS
Feature requests: Add arrow buttons for mobile navigation, Fix keyboard controls to match standard FPS (W forward, S backward)
Competitors
Other products that read as similar to this one : 90 launches clear the similarity bar, closest 8 shown.
Attention rank: #1 of 91 (itself plus its competitors, highest first, normalized so YC and Product Hunt are compared fairly).
Launched 292 days after the earliest competitor.
- I built a space travel calculator using Vanilla JavaScript · hn · 2026-01-24 · 54 upvotes · similarity 0.55
- A gravity simulator where forces propagate at the speed of light · hn · 2026-09-03 · 6 upvotes · similarity 0.52
- Space on Live · ph · 2026-10-07 · 1 upvotes · similarity 0.47
- Gravity · hn · 2026-06-09 · 217 upvotes · similarity 0.47
- The Emergence of Time and Space · ph · 2026-09-18 · 1 upvotes · similarity 0.41
- Does Information Density Cause Time Dilation? · hn · 2025-12-24 · 10 upvotes · similarity 0.41
- CalculUnits · ph · 2026-10-12 · 1 upvotes · similarity 0.40
- Algorithmically finding the longest line of sight on Earth · hn · 2026-02-09 · 412 upvotes · similarity 0.39
The niche, labels, vibe code rating and competitor comparison on this page are analysis by Nicheloom. If you use them, please credit nicheloom.com. How you may use our data.