When a massive star runs out of fuel, it collapses and explodes as a supernova. An instant before the catastrophe, neutrinos — ghostly particles — burst from the core. They rush through the star and interstellar space like the smell of smoke, heralding a fire that will only ignite minutes or even days later. Light, on the other hand, needs time to break through the dense shells.
Underground detectors catch this 'smoke' — a few particles out of an unimaginable torrent. Upon receiving the signal, the Vera Rubin Observatory turns its colossal eye to the right spot. It will glimpse the glow of a newborn neutron star and the dispersing gas. Calculations show: between 57 and 97 percent of supernovae in our Galaxy will be caught.
The ideas of Fritz Zwicky and Hans Bethe back in the last century linked neutrinos to the death of stars. Today, rapid photometry (brightness measurement) will allow us to trace the entire process: from collapse to the dispersal of the envelope.
Neutrinos from the SN 1987A explosion reached Earth three hours before the light — and that's despite a distance of 168,000 light-years.