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We only keep your email and the username you choose. We never share or sell your email, and we don't send marketing — we use it only to email you a sign-in code. Read our privacy policy.

About TerraForge

TerraForge is a planet-building tool and an exoplanet reference, built to make planetary science tangible instead of abstract.

What you can do here

Mix elements, pick a star, add moons, and watch the simulation classify what you've built — rocky, gas giant, water world, and more — then simulate billions of years of evolution in seconds. Save a world and share it with a link, or browse what other people have built.The same engine also renders every planet in NASA's Exoplanet Archive that has enough measured data to simulate — thousands of real, confirmed worlds, each built from its actual measured mass, orbit, and star, not a guess.

The physics, honestly

The simulation is a model, not a lab: it uses real relationships between mass, density, stellar radiation, and composition to classify a planet, but it simplifies where a full physical simulation would be impractical for something that needs to run instantly in a browser. Where the model and a real exoplanet's own measurements disagree, the page says so rather than quietly picking one over the other — see the note on any exoplanet page.

Built with

Next.js, Three.js, and Space UI.

Questions or feedback

Reach out through the contact page, or read the guide for a full walkthrough of the builder.
A binary star system's orrery: two suns close together, a red dashed dead-zone boundary, and a debris trail left by a destroyed world

New: Binary Star Systems 🌀

A system can now orbit two suns. Add a companion star when you build one — close, medium, or wide — and the physics decides what survives: a shared center of mass carves out a dead zone where gravity from both stars tears a world apart, leaving it as debris, and every surviving planet's orbit goes elliptical, moving fastest at closest approach and slowest out at aphelion. Push the separation to wide and the dead zone opens tens of AU across, wide enough to gut a system that would have been stable around one star alone. Stand on a world that made it through and you'll watch two suns cross the sky together.

Create your free account

Enter your email and we'll send a 6-digit code — no password needed.
We only keep your email and the username you choose. We never share or sell your email, and we don't send marketing — we use it only to email you a sign-in code. Read our privacy policy.

Send feedback

We're still building out the best experience we can — and we'd love your input. Tell us about features you enjoy, ideas you'd like to see, or pain points where something feels off, and we'll know where to look next.

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