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I think there are actually two forces at play, according to the article: gravity and degeneracy pressure. One the one hand, the neutrons are stable and not decomposing into protons, electrons, etc. by the extreme gravity. At a previous point in the star's lifecycle, it was comprised of normal atoms which contain electrons, protons, and neutrons. In atoms under typical conditions, there is a force which keeps the electrons from falling into the nucleus. Later in the star's life, as the star ran out of fuel, gravity overcame the force that normally keeps electrons from falling into the nucleus and so the protons and electrons fused to become neutrons. Hence, a neutron star. If one were to release the gravitational pressure, the neutrons would become unstable and you'd get the decay back to protons, electrons, and the radiation that's mentioned. It would be a huge release of energy, as the article states. The degeneracy pressure is the other force at play. It's what keeps the neutrons from collapsing onto one another and becoming a black hole. I think it's essentially the Pauli exclusion principle, but I could be wrong there. So, the degeneracy pressure keeps them separated as individual neutrons, but gravity is what is stabilizing the neutrons themselves as neutrons. If the star were large enough, gravity would overcome even the degeneracy pressure, resulting in a black hole. At least, I think that's how it works. |