How to Reconcile Two Neutron Stars ⚡ экспресс
Gravitational waves from events GW170817 and GW190814 described the properties of superdense matter differently. By applying an evolutionary search for equations of state, physicists found a large family of compatible models. They predict a maximum neutron star mass up to 2.8 solar masses, a radius of about 12 km, and tidal deformability ≤580. The main feature is a double-humped speed of sound, reaching 99% of the speed of light. This suggests that inside such stars, matter can layer like oil and water, not mixing completely.
A neutron star is a superdense pie, and its equation of state is the dough recipe. The stiffer the dough, the less the star deforms when squeezed. Observations of two gravitational-wave bursts—GW170817 (merger of two neutron stars) and GW190814 (a neutron star swallowed by a black hole)—gave conflicting hints: one required a soft recipe, the other a stiff one. Like obsessed bakers, scientists sifted through thousands of compositions and found a family of recipes where the filling becomes two-layered, and sound inside races at nearly the speed of light. Only a few dozen out of thousands passed the strict test of observations.
Thus they managed to reconcile the data on the merger of two neutron stars and the absorption of one by a black hole, without going beyond Einstein's theory.
🎯 If someone shouted inside a [tag:neutron_star]neutron star[/tag], the sound would circle Earth 7 times per second—its speed is comparable to the [tag:speed_of_light]speed of light[/tag].
🎬 In Larry Niven's story 'Neutron Star,' the hero survives near such an object. Reality turns out to be no less exciting.