In the final moments of a massive star's life, nearly invisible particles called neutrinos carry within them the answer to one of astronomy's oldest questions: will the star die in a brilliant explosion, or vanish silently into a black hole? Scientists have discovered that the way neutrinos shift between identities as they stream through a collapsing stellar core may encode the star's ultimate fate. This research, still in its early stages, positions humanity on the threshold of reading messages written in the language of ghost particles — messages that have been traveling through the cosmos s