Roman Space Telescope Could Weigh Hidden Neutron Stars via Gravitational Microlensing

NASA’s Nancy Grace Roman Space Telescope could spot and weigh isolated neutron stars in the Milky Way using astrometric microlensing in its Galactic Bulge Time Domain Survey; by tracking tiny shifts in background starlight as a neutron star passes in front, Roman can directly measure the masses of otherwise invisible remnants, helping map the neutron star–black hole population and shedding light on neutron-star birth kicks, with even a few detections significantly advancing stellar evolution models.