Silent Messengers: Neutrinos Illuminate Hidden Galactic Explosions

Avi Loeb explains that neutrinos from Galactic supernovae penetrate interstellar dust and reveal explosions that optical observations often miss. The 1987 SN 1987A produced 24 neutrinos detected by Kamiokande-II, IMB, and Baksan, enabling estimates of the explosion’s energy and the newborn neutron star’s properties. Today’s and forthcoming detectors—Super-Kamiokande, JUNO, IceCube, Hyper-Kamiokande, and DUNE—could observe thousands to tens of thousands of events from a Milky Way supernova, allowing measurements of neutrino masses and oscillations as well as the neutron star’s mass, radius, and binding energy. Webb’s 2022 observations of a neutron-star signature in SN 1987A underscore the potential of neutrino astronomy for probing fundamental physics and stellar remnants.