I made a planet renderer using a unit cube. INSIDE the unit cube is 12 million^3 blocks that represent possible voxel blocks that can make up the planets data(at the surface). I need a way to match the space representation of the planet with the voxel representation at the surface, but my big concern is that I don't know if I will be able to generate enough noise detail to be able to do this.

So basically my question is this. If I generate 3D noise representing the cube of data(12 million^3), and use the sides of the 3d noise "cube"[within -1,1] to represent my heightmap for the planet, is it possible to generate enough detail to have a real to scale planet? Or would this just take too many octaves to do.I need to be able to have a detailed enough noise function that can sample values between [-12,000,000 to +12,000,000] and have coherent noise in these ranges representing the data of the planet.

I am just lost as to how to go about combining these two ideas(polygons from space and voxels at surface) using the same noise method so when I switch from space to surface the data is the same.

Thanks for any guidance.