In 2017 gravitational waves, oscillations of space-time, were detected from the collision of two neutron stars. This historic event provides new insight into very dense neutron rich matter. We compare these observations to the PREX II experiment. PREX uses parity violating electron scattering to precisely locate the 126 neutrons in 208Pb. Despite differing in size by 18 orders of magnitude, both the Pb nucleus and a neutron star are made of the same neutrons, with the same strong interactions, and have the same equation of state (pressure as a function of density). Therefore, PREX II has important implications for neutron star mergers and the structure of neutron stars.