I built a space travel calculator using Vanilla JavaScript
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I built this because measuring my age in years felt boring—I wanted to see the kilometers.The first version only used Earth's orbital speed (~30km/s), but the number moved too slowly. To get the "existential dread" feeling, I switched to using the Milky Way's velocity relative to the CMB (~600km/s). The math takes some liberties (using scalar sum instead of vector) to make the speed feel "fast," but it gets the point across.Under the hood, it's a single HTML file with zero dependencies. No React, no build step. The main challenge was the canvas starfield—I had to pre-allocate the star objects to stop the garbage collector from causing stutters on mobile.Let me know if the physics makes you angry or if the stars run smooth on your device.
HN · launched Jan 24, 2026 · 54 upvotes (top 19%) · 0 views
Niche: specialized calculation tools · 551 launches, 66 in the last 7 days ▼ -7% · Explore this niche →
Category and tags
- Horizontal
- Dev tools
- B2C
- Not AI
- Hobby / open-source project
Visit website ↗ Source listing ↗
More like this: all 551 launches in specialized calculation tools →
Could you build this?
Yes A single-page vanilla JavaScript utility that multiplies elapsed time by cosmic velocity constants and displays it on an odometer.
Discussion
20 comments analyzed.
Competitors mentioned: three.js for star rendering, other cosmic distance calculators
Concerns raised: LLM-generated code and comments, lack of transparency about AI usage, Window resize breaks star background rendering, Logarithmic scale needed to visualize solar and galactic distances together, UI labels unclear/confusing for new users, CPU usage on mobile devices
Feature requests: Fix viewport resize jank with star rendering, Logarithmic scale option for distance visualization, Clearer UI labels/onboarding, Three.js integration for better star effects and performance
Competitors
Other products that read as similar to this one : 214 launches clear the similarity bar, closest 8 shown.
Attention rank: #42 of 215 (itself plus its competitors, highest first, normalized so YC and Product Hunt are compared fairly).
Launched 85 days after the earliest competitor.
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- A browser game where you navigate home to Earth using pulsars · hn · 2026-11-01 · 5 upvotes · similarity 0.53
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- farseer.space · hn · 2026-09-15 · 11 upvotes · similarity 0.49
- Blender Copilot · hn · 2026-09-26 · 6 upvotes · similarity 0.47
- A solar system simulation in the browser · hn · 2025-12-29 · 13 upvotes · similarity 0.46
- Swayanta · ph · 2026-11-10 · 2 upvotes · similarity 0.46
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