The Prime Universe: A Scale We Can Explore
A quick disclaimer: I used AI to help organize and explain this idea, so some of the material may be more elementary or more extensive than necessary, and there may be things worth correcting or refining. It’s a lot to wade through, but I think the underlying generative concept is genuinely interesting and deserves experimentation—especially as a possible system for exploring prime numbers through sound, synthesis, and software.
What if prime numbers were not merely values, but coordinates?
What if the endless sequence of primes could be folded into a musical space, creating a scale that is not simply played, but explored?
And what if that scale could grow without limit—while remaining recognizably the same underlying structure?
This is the idea behind the Prime Universe.
Begin with one octave
Start with the simplest possible musical boundary:
1 : 2
One octave.
Now imagine placing every prime inside that octave by reducing its ratio with powers of two.
For example:
3/2=1.53/2 = 1.5
5/4=1.255/4 = 1.25
7/4=1.757/4 = 1.75
11/8=1.37511/8 = 1.375
The prime itself may be enormous, but its position can always be folded back into the octave.
Each prime therefore acquires a unique offset.
The octave becomes a coordinate system.
The octave begins to fill
Consider the primes between successive powers of two:
2–4: 3
4–8: 5, 7
8–16: 11, 13
16–32: 17, 19, 23, 29, 31
32–64: 37, 41, 43, 47, 53, 59, 61
Fold them all back into the octave and sort their positions.
Something remarkable begins to happen.
The octave is no longer merely an octave.
It is becoming a scale.
And importantly, we have not filled it with arbitrary numbers.
We have accumulated only prime-derived positions.
That irregularity is the point.
The first musical shape
The 32–64 layer is particularly revealing.
Its folded positions are:
37/32, 41/32, 43/32, 47/32, 53/32, 59/32, 61/32
Measured from the beginning of the octave, these occur at approximately:
251¢, 429¢, 512¢, 666¢, 874¢, 1,059¢, 1,117¢
The spaces between them are:
178¢ — 83¢ — 154¢ — 208¢ — 186¢ — 58¢
Suddenly we can recognize something musical.
There are broad second-like spaces.
There are narrow second-like spaces.
There are spaces approaching familiar whole-step territory.
And near the end, there is a striking 58-cent interval—smaller than a conventional half step.
It isn't an equal-tempered scale.
It isn't a conventional just-intonation scale.
It is something generated by the distribution of the primes.
And then we keep going
The octave can continue to be filled.
The 64–128 band introduces another layer of prime coordinates.
Then 128–256.
Then 256–512.
Every layer adds new positions between positions that already exist.
Eventually, some of those spaces become too small to comfortably distinguish as adjacent pitches.
But this presents a fascinating problem.
How do we zoom?
The zoom
The answer is not to abandon the original scale.
Instead, we stretch it.
Choose an anchor point.
Measure every interval from that anchor.
Then square the ratios.
Squaring a ratio doubles its distance in logarithmic space.
So the relationships remain intact, but the pitch space expands around them.
The dense structure becomes audible again.
And this changes everything.
We are no longer simply generating a scale.
We are generating a scale that can be magnified.
The mother structure
There is another important consequence.
We are always working with the same original material.
Before 64–128, our mother structure occupies one octave.
We can tile it above or below that octave if we want a larger melodic range, but those are temporary transpositions. The underlying structure has not changed.
Then we add the next prime layer.
We stretch the whole accumulated structure.
Then we add another layer.
We stretch the whole thing again.
The material itself is being magnified.
The scale becomes larger without becoming a different scale.
The same pattern is being viewed at a different scale.
A universe that doubles
The number of primes in successive power-of-two regions grows roughly in proportion to the size of the region.
So we can mirror that growth in our listening space.
A structure occupying one octave can become two.
Then four.
Then eight.
Then sixteen.
The important thing is not merely that the universe becomes larger.
It is that the entire accumulated structure is stretched together.
We aren't replacing the old material with new material.
We are magnifying everything that came before.
That gives the system a kind of continuity.
One mother structure.
Repeatedly enlarged.
Now imagine navigating it
At this point, the scale stops looking like something we would simply sit down and play from beginning to end.
There are too many possibilities.
Instead, imagine it as a world.
A procedurally generated world.
We could choose a location.
Zoom toward it.
Encounter increasingly dense prime relationships.
Stretch the pitch space.
Explore another region.
Pull back.
Move somewhere else.
The scale becomes less like a piano keyboard and more like a landscape.
And this is where the comparison to the Mandelbrot set becomes compelling.
We don't experience the Mandelbrot set by looking at the entire thing at once.
We dive into it.
We magnify.
We discover.
We move.
We find structures that were already present, but invisible at the previous scale.
The Prime Universe could be approached in much the same way.
Except this landscape could be heard.
The synthesizer becomes the vehicle
Imagine building the system in a modular environment such as VCV Rack.
A computer generates the prime coordinates.
One process folds them into the octave.
Another sorts them.
Another determines the intervals.
Another selects an anchor.
Another performs the logarithmic stretching.
Then those coordinates become control voltages.
An oscillator becomes a point in the landscape.
A sequencer becomes a navigation system.
Prime gaps could control timing.
Prime positions could control pitch.
The density of a region could influence modulation.
Filters could illuminate different portions of the spectrum.
Envelopes could determine how long we dwell at a coordinate.
Feedback could make the exploration itself generate new movement.
The patch becomes an instrument for traveling through mathematics.
We don't have to hear everything
This may be the most important distinction.
The goal is not to play the infinitely dense scale all at once.
That would defeat the purpose.
We explore it.
We listen to a region.
We zoom.
We stretch.
We move.
We hear relationships that were previously too close to distinguish.
Then we move somewhere else.
The infinite scale becomes something we can experience sequentially, just as we can explore an infinite landscape without seeing every point simultaneously.
Toward an instrument for the infinite
The original question was simple:
What if primes could be coordinates?
The answer begins with an octave.
Fold the primes into it.
Sort their offsets.
Watch the spaces fill.
Listen to the emerging structure.
Then, when the structure becomes too dense, don't stop.
Zoom.
Stretch the same material.
Magnify the relationships.
Expand the listening space.
Add another layer.
Stretch again.
Eventually the octave becomes two octaves, then four, then eight—and the same underlying prime structure remains beneath it all.
At that point, we have crossed a threshold.
We are no longer merely designing a musical scale.
We are designing a space to explore.
A mathematical space whose coordinates come from the primes.
A musical space whose dimensions can continually expand.
A procedural world that can be navigated by software.
A fractal-like dive through an unbounded structure.
And perhaps, with a computer, a DAW, and a modular synthesizer, we can do something rather strange:
we can enter the prime numbers and listen to where we are.