No Man's Sky is a massive game — not in terms of its size on your hard drive, but the size of the universe within the game. If you're anything like me, you might have seen that the game will have 18,446,744,073,709,551,616 planets and thought, "How is that even possible?"
Admittedly, it's still a difficult concept to understand even once you have all the details. But today, we're going to try to give you those details in the easiest way to understand possible!
What's so special about that exact number?
If you saw 18,446,744,073,709,551,616 and assumed the No Man's Sky team at Hello Games decided to just hit numbers until they were satisfied with the randomness of the assortment, you'd be wrong. I mean, it's a perfectly valid guess, but wrong all the same.
That number actually has to do with the fact that the game was created in a 64-bit system. A 64-bit system is named as such because it can store precisely 2^64 different values.
Before you bust out your calculators, yes, 2^64 is 18,446,744,073,709,551,616. In other words, Hello Games decided to take the computing system it was working with and push it, quite literally, as far as it could go.
With that in mind, it's still hard to picture how anyone — let alone the small team of 10 the encompasses Hello Games — could ever create that many planets. Well, technically, they didn't.
Each planet is a "seed" in the system that is randomly generated from different variables.
Think of it this way: Hello Games decided which variables would be in the game — for example, plant life, animal life, terrain, and so on — and then gave variants to each of these variables — color, size, shape, etc..
With enough variables, and enough variants to those variables, the computer program that No Man's Sky uses is able to combine them in every way possible. Each of those possible combinations of all of the variables and variants is one "seed."
"The cool thing is that every planet has a single number, a random seed, that defines everything about that planet. A single random seed generates every blade of grass, tree, flower, creature."
In other words, the team designed the tools that helped set everything else in motion — they planted the seeds, the computer made them grow.
Each and every one of these seeds is one of the values stored in the 64-bit computing system, which is why the game maxes out at 18 quintillion planets.
How can all this exist at once without overloading my system?
Here's the trick to it all: The game procedurally generates the content. Procedural generation is a fancy way of saying that something doesn't exist in a physical sense until you get close enough to see it. If you can see it on your screen — a star, a moon, another planet — the computer has generated data about it in some capacity (with more distant objects having less data generated). But if you can't see it, the game won't load it until you can.
In a way, it's sort of like your character is running on a virtual, 3D treadmill, with the space in front of you being generated as you move toward it at the same rate the space behind you is being un-generated.
For Rick and Morty fans, it's kind of like what happens in the episode "M. Night Shaym-aliens," if that visual is easier to grasp.
Another way to think of it is that your character has an invisible "box" around themselves and this box does not change size. Anything within the bounds of that box will be generated by the computer, anything outside it will not. As you move, the box moves with you. Your game will never generate anything more or less than what fits inside this box.
It's all a bit complicated to grasp — if nothing else, you can always fall back on the all-encompassing explanation, "Magic!"