Lets just say a 256 bit number represents all the matter in the milky way galaxy and then a ton more. There isn’t enough spin states to cover that in anything called reasonable on an astronomical scale.
Our galaxy, the Milky Way, contains approximately 100 to 400 billion stars. If we take this as 200 billion or 2 × 10^11 stars and assume that our sun is a reasonable average size we can calculate that our galaxy contains about (1.2 × 10^56) × (2 × 10^11) = 2.4 × 10^67 atoms.
The Hubble space telescope tells us that there are about 100 billion or 10^11 galaxies in the whole universe. So again, if we assume that our galaxy is average, we get that the number of atoms in the universe is about 2.4 × 10^67 × 10^11 = 2.4 × 10^78. Internet research gives answers of around number of atoms image 3
Actually then, a 256 number (approx 10^77) is 10 times to 10,000 times smaller than number of atoms in the known universe. But with 100,000,000,000 galaxies its still close LOL.