When a star the size of 20 suns dies, it becomes, “the most outrageous object that most people have never heard of” — a city-size body of improbable density known as a neutron star. A chunk of neutron star the size of a Ping-Pong ball would weigh more than a billion metric tons. Below the star’s surface, under the crush of gravity, protons and electrons melt into one another to form a bulk of mostly neutrons — hence the name. At least, that is what we think.
The issue is far from settled. Astronomers have never seen a neutron star up close, and no laboratory on Earth can create anything even approaching the same density, so the inner structure of these objects is one of the greatest mysteries in space.
Jocelyn Read, a Cal State Fullerton astrophysicist, is among those commenting on the matter.
“It’s starting to make our equation of state thread a needle path through these different observations,” says Read, co-leader of LIGO’s Extreme Matter team. “Trying to make compact stars, as well as supporting massive stars, is getting to be challenging to the theory. It’s definitely interesting and might get more interesting.” Continue reading in Scientific American.