"While nuclear pasta has not been observed in a neutron star, its phases are theorized to exist in the inner crust of neutron stars, forming a transition region between the conventional matter at the surface and the ultra-dense matter at the core.
Towards the top of this transition region, the pressure is great enough that conventional nuclei will be condensed into much more massive semi-spherical collections. These formations would be unstable outside the star, due to their high neutron content and size, which can vary between tens and hundreds of nucleons. This semispherical phase is known as the gnocchi phase.
When the gnocchi phase is compressed, as would be expected in deeper layers of the crust, the electric repulsion of the protons in the gnocchi is not fully sufficient to support the existence of the individual spheres, and they are crushed into long rods, which, depending on their length, can contain many thousands of nucleons. These rods are known as the spaghetti phase. Further compression causes the spaghetti phase rods to fuse and form sheets of nuclear matter called the lasagna phase. Further compression of the lasagna phase yields the uniform nuclear matter of the outer core. Progressing deeper into the inner crust, the holes in the nuclear pasta change from being cylindrical, called by some the bucatini phase or antispaghetti phase, into scattered spherical holes, which can be called the Swiss cheese phase.
The nuclei disappear at the crust–core interface, transitioning into the liquid neutron core of the star.
The pasta phases also have interesting topological properties characterized by homology groups."