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How Moon Miner builds a Moon out of one number

The world is calculated, never stored

Moon Miner hands you a mining pod and a Moon full of rock, ore, caves and gas pockets. None of it exists as a map. There is no file anywhere containing the layout of your Moon. There is one number, and everything else is worked out from it as your drill arrives.

That number is called a seed. When you start a new world, the game picks a random whole number and keeps it. That single value is the entire Moon.

Every tile is a calculation, not a lookup

The Moon is a grid of tiles. When the game needs to know what a particular tile is, it does not look the answer up. It works it out from three things: the seed, the tile's column, and the tile's row.

The tool that does this is called a hash. A hash takes some numbers, scrambles them thoroughly, and hands back a result that looks completely random. The important part is that it is not random at all. Feed the same numbers in and you get the same answer back, every single time, forever. That property is called determinism, and it is what makes the whole trick work.

So the question "is there ore here?" costs a little arithmetic to answer and nothing at all to store. Ask it a thousand times and you get the same answer a thousand times.

Where the ore goes

Pure hashing would sprinkle minerals evenly across the rock like static on an old TV, which would be boring to dig. Real ore comes in veins.

So the game layers a second thing on top: a noise field. Noise here means a smooth, rolling landscape of values, high in some places and low in others, grown from the same seed. Wherever that field rises above a set level, the game calls that patch of rock a vein and fills most of it with minerals. Because the field is smooth, veins come out as connected blobs rather than confetti.

On top of that, plain rock has its own small chance of hiding a lone mineral. Those scattered singles are actually the bulk of what you dig up. The veins are the payday.

Which mineral you get depends on how deep you are. The Moon is divided into layers, and each layer has headline minerals of its own plus a smaller share of the ones from the layer above, so the boundaries blend instead of snapping. The deepest layers also hand out far fewer minerals, which is why the deep pays better per tile but hands you fewer of them.

How the caves get carved

Caves use an older and stranger technique. The game starts by marking tiles open or solid at random from the seed, a little under half of them open. The result is meaningless noise. Then it applies one rule, over and over: look at a tile together with its neighbours, and if most of them are solid, that tile becomes solid too. Everything else becomes open.

Run that rule once and the noise gets slightly clumpier. Run it a few times and it settles into smooth, rounded caverns with real walls and passages, as if someone had carved them. Nobody drew those caves. They fell out of a rule that was applied until it stopped changing much.

What the save file knows about the Moon

The payoff for all of this shows up when the game saves. The Moon runs to tens of thousands of tiles. Your save describes none of them.

It records your credits, your upgrades, your cargo and where your pod is, the way any game would. The world itself, though, comes down to two things: the seed, and a single yes or no per tile answering the only question the game cannot recalculate, which is whether you have dug there yet. That fits in a few kilobytes, and it shrinks further because long runs of untouched rock collapse into one entry. Load the game and it rebuilds the whole Moon from the seed in an instant, then paints your tunnels back on top.

Your dug tunnels are the only part of the world that is genuinely remembered. Everything else is worked out again on demand.

Does the Moon have a bottom?

It does, and it is closer than the endless-feeling rock suggests. The layers run out, and below them sit a core chamber, a thin band of root tiles, and then bedrock. That really is the end of the world.

What sells the illusion is not endless generation. It is that the root floor cannot be drilled. The game gives it infinite hardness, so no drill will ever break through it and nobody ever reaches the seam where the rock stops being invented. A wall you cannot pass looks exactly like a world that goes on forever.

One last consequence of building a world this way: because it is a pure calculation, two people with the same seed get the same Moon. Same layers, same caves, same veins, same gas pockets, in the same places. Not a copied map. The same sum, worked out twice.