Hey Product Hunt, I built FineTune because I’ve always been fascinated by one question: “What would happen if the laws of physics were slightly different?” I wanted to build something that lets you experiment with the rules of the universe itself. FineTune lets you modify fundamental constants like gravity, the speed of light, quantum effects, and electromagnetism, then see how those changes ripple through atomic structure, stars, planetary systems, and cosmic stability in real time. One of the hardest parts was balancing scientific realism with interactivity. Early versions were mostly “physics-inspired,” but over time I rebuilt large parts of the engine around actual scaling relationships from atomic and stellar physics while still keeping it understandable and fun to explore. This project became part physics sandbox, part educational tool, and part thought experiment about how fragile, or resilient, our universe really is. Would love to hear what universes you create, what breaks first, and what features or physics systems you’d want to see next!

FineTun Physics

FineTune: Explore universes by rewriting physics

FineTune: Explore universes by rewriting physics