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Volcanic Worlds

Cold worlds kept molten from within by their moons.

A volcanic world is not melted by its star - it is kneaded by its moons. Close-in moons in a resonant configuration pump the planet's tides, and the flexing dissipates enormous heat inside it. Volcanism resurfaces the world continuously while the ground between the vents stays as cold as the orbit allows. Jupiter's moon Io is the real example: an equilibrium temperature near 110 K, and lava lakes at 1600 K on the same surface. Give a comfortable orbit two close-in moons to build one.

See all volcanic worlds on Explore

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.

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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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