Neutron Stars — Brief Overview

Published: February 26, 2023

Neutron stars (NS) are interesting because they represent extreme objects in which many physical quantities are pushed to their maximum (gravitational and electromagnetic fields, conductivity and fluidity). We cannot create this in laboratory conditions, but space gives us a so-called "poor man's laboratory," where there is an opportunity to study such objects.

For example, with the help of NS we can study matter at very high densities. Under normal conditions, we only deal with the density of an atomic nucleus, which the strong interaction does not allow us to exceed. It is very difficult to overcome. Yes, there is a possibility to collide two nuclei in an accelerator, but then we get hot plasma. In neutron stars, however, we can study this matter in a "cold" state.

The density of matter in the center of an NS can be 10 times greater than that of an atomic nucleus. Usually there are equal amounts of protons and neutrons in matter, but in an NS there can be 9 times more neutrons. But, despite the name, their quantity may not exceed 10-20%.

Under pressure, matter in the center of an NS is compressed, and electrons and protons merge into neutrons. This achieves the maximum possible density of matter. If we continue to "throw" more matter onto an NS, then, upon reaching a mass greater than 3 solar masses, it will turn into a black hole.