Draw a random alien planet type -- ocean worlds, tidally locked eyeballs, ringworlds and tomb worlds -- each with what makes it what it is.
This generator draws from 114 kinds of planet across seven groups, from classes astronomers genuinely argue about (chthonian planets, super-Earths, rogue worlds) to the megastructures and ruins that only exist in fiction. Each result describes what the world actually is rather than just naming it, so it's a starting point you can build on immediately.
Every result here is drawn using crypto.getRandomValues() -- the Web Crypto API's cryptographically secure randomness -- instead of Math.random(), so it's genuinely unpredictable, not just statistically random. Learn more.
Game masters use it to invent a destination between sessions. Science fiction writers use it when a story needs somewhere specific rather than a generic planet, and it's the first block of the Random Alien World preset, which then adds terrain, inhabitants, a civilization and a hazard.
Generate draws one planet type at random using the site's cryptographically secure randomness, guaranteed not to repeat whatever result is currently showing in single-result mode. Filter by group to stay inside hard-science classes, or inside the built and ruined ones.
A sample of what this generator can draw, spread evenly across the full list:
Many are. Ocean worlds, chthonian planets, hot Jupiters, super-Earths, rogue planets and eyeball worlds are all real classes that astronomers use. Others -- ringworlds, shellworlds, tomb worlds -- are science fiction, and are grouped separately so you can filter them out.
A tidally locked planet with one face permanently towards its star. The melted ocean on the day side is ringed by ice, so from space it looks like an eye. It's a genuine and much-discussed class of potentially habitable exoplanet.
Yes -- filter to Habitable & Marginal. Or filter to Dead & Ruined if you want somewhere that used to be.
Use the Random Alien World preset, which stacks this with Alien Biome, Alien Species, Alien Civilization and World Hazard so one press gives you a place, its people and its problem.
Alien Species · Alien Biome · Alien Civilization · World Hazard · Spaceship Name · Sci-Fi Gadget