A state of matter last seen just after the Big Bang may exist inside neutron stars — and scientists think they can prove it

We could soon be able to "see" inside a neutron star and learn what extreme matter governed by exotic physics lurks there, thanks to the imprint of tidal interactions on gravitational waves emitted by pairs of neutron stars spiraling toward an explosive merger.

"One hope is that we'll be able to get some information about the neutron-star equation of state at densities found in the inner core of a neutron star," said Nicolás Yunes of the University of Illinois, who led the research, in a statement. "Is there really a quark core, as some have recently claimed? Are there phase transitions occurring inside that we don't know about yet?

A neutron star is the compact remnant of a massive star that has gone supernova. With a diameter about the same as a large city, yet packing a mass several times that of our sun, neutron stars are incredibly dense. The pressure in their interior is so great that atoms are crushed and split apart into their constituent particles.