Scientists have uncovered a new key to understanding the strange workings of neutron stars — objects so dense they pack the mass of multiple suns into a space smaller than a city.
It turns out there is a universal relationship linking a trio of properties related to how fast the star spins and how easily its shape deforms. This relationship could help astronomers understand the physics inside neutron stars’ cores, and distinguish these stars from their even weirder cousins, quark stars.
Neutron stars are born when massive stars run out of fuel for nuclear fusion and collapse. They expel their outer layers, and their cores fall inward under the pull of gravity to become denser and denser. Eventually, the pressure is so great that even atoms cannot retain their structure, and they collapse. Protons and electrons essentially melt into each other, producing neutrons as well as lightweight particles called neutrinos. The end result is a star whose mass is 90percent neutrons.