Neutron Star Structure

A neutron star has a layered interior that tests the limits of known physics. The outer crust is a rigid lattice of iron nuclei and electrons. Deeper down, nuclei become so neutron-rich they form exotic shapes physicists call nuclear pasta — sheets, tubes, and blobs that may be the strongest material in the universe.

Below the crust lies a superfluid ocean of neutrons that flows without friction. The innermost core may hold quark matter — quarks freed from their usual confinement inside protons and neutrons. No lab on Earth can recreate these conditions, making neutron star interiors one of the few places truly exotic states of matter exist.