Abstract: With densities going above 6 times nuclear matter densities, the core of neutron stars are our only laboratories to study high density nuclear matter and QCD. The composition of such cores is unknown, but after the measurement of the super massive pulsar PSR-J1614, the question of whether or not hyperons may be present in these stars, or perhaps completely deconfined quark matter, became extremely pressing. Nowadays, new data from the gravitational waves GW170817 give us some new constrains and help us to understand what goes on in such dense objects. In this talk I will give a brief overview of the quark-meson coupling model for nuclear interactions and show how it helps shed some light into these issues.