In Neu Theory, a surface of closure is the part of an object that serves as the boundary between the object and its environment. The surface of closure is a finite area that can be measured by any unit of choice. In the Neu Theory model there are only three discrete surfaces in nature:
- The first (S1) defines the proton and the neutron core.
- The second (S2) and the third (S3) always appear together, and define the neutron membrane, and the electron ball.
The three surfaces topologically define the hollow volume as either:
- a-state, the closed hollow of the neutron cell.
- b-state, the open hollow of the electric ions and space.