Show HN: The Atlas – I Built a 3D Universe Simulation with Python and Three.js https://ift.tt/GZ26MIQ

Show HN: The Atlas – I Built a 3D Universe Simulation with Python and Three.js Hi HN! I’ve spent the summer of the past 2 years building The Atlas, a procedural universe simulator that generates 1 sextillion galaxies (10²¹) from a single mathematical seed. Think No Man’s Sky meets theoretical physics, but running entirely in your browser. Everything is purely deterministic, the universe is calculated from SHA-256 hashed seeds using the golden ratio as primordial constant. There’s no database, no pre-saved data, just pure math. Time itself is treated as a coordinate, so the universe exists as a 4D structure where any moment can be computed on demand. Shut it down for weeks, restart, and planets have still been orbiting. Open the same world on multiple devices and you’ll see identical cloud formations, lava flows, even particle effects—always perfectly synchronized (if your clocks are synced). The simulation applies real physics, Kepler’s laws, tidal locking, Roche limits, hydrostatic relaxation for moons, and orbital temperature variations. Scale is mind-boggling, 300 tredecillion potential planets, far beyond anything that could ever be explored. The backend runs on Python/Flask with Hypercorn, the frontend on React + Three.js, connected via a custom MIT-licensed “vite-fusion” plugin we made. Everything is generated in real time, no storage needed. The Atlas includes 26+ planet types, fictional elements, moons evolving over geological timescales, and rare life forms that display Arecibo-style messages when analyzed. There’s resource mining and spaceship progression as gamification features. At its core, it’s a playable implementation of Einstein’s block universe theory, all moments exist simultaneously in the mathematical structure, you’re just moving through different temporal slices. You can try the live demo or run your own universe locally. When installed, you can choose between Core Continuum (a shared seed universe evolving since 1986, my birth year) or Design the Multiverse (your own unique cosmos with a fresh seed). I’d love feedback on the procedural generation algorithms and ideas for expanding the physics simulation! - GitHub: https://ift.tt/nZu3KCL - Docker: bansheetech/atlas:latest - Demo: https://the-atlas.koyeb.app - Alt Demo: https://ift.tt/l8KOWQN Thanks for reading this far! <3 https://github.com/SurceBeats/Atlas September 21, 2025 at 09:26PM