What physical force is responsible for halting the gravitational collapse once protons and electrons merge into neutrons?
Answer
Neutron degeneracy pressure
Gravity overcomes electron degeneracy pressure, forcing the elements to merge; the collapse is then stopped by the pressure generated by the neutrons themselves, known as neutron degeneracy pressure.

Related Questions
Which celestial body is defined as the densest known object that is still technically classified as a star?What catastrophic stellar event often marks the birth of a neutron star?What physical force is responsible for halting the gravitational collapse once protons and electrons merge into neutrons?If a teaspoon of material from a neutron star's interior could be weighed, what approximate mass would it have?What is the typical radius range for a neutron star, compressing solar mass into a tiny volume?What causes the characteristic periodic pulses detected from objects designated as pulsars?Why do neutron stars possess extremely rapid rotation rates after their formation?The outer crust of a neutron star is composed of which primary structural elements suspended in electrons?What is the main unresolved uncertainty regarding the internal structure of a neutron star?What celestial object is considered denser than a neutron star?