Hello. I am wondering what are the properties of matter at the core of a neutron star. I read that it could be quark matter of strange matter, but overall uncertain. How can strange matter form if strange quarks decay very quickly into up quarks (the state of matter would last very shortly), and where would the strange quarks come from? Why do they start to matter at extremely high temperatures and pressures? Is it possible to experimentally detect and study the core of a neutron star to be sure? Thank you in advance.