All models that explain Type Ia supernovae begin with a white dwarf in a pair of stars. Now, astronomers have captured a new image that proves their hunch was right: at least some Type Ia supernovae explode through a ‘double-detonation’ mechanism instead. In this alternative model, the white dwarf forms a blanket of stolen helium around itself, which can become unstable and ignite. Until now, there had been no clear, visual evidence of a white dwarf undergoing a double detonation. This provides strong evidence that a Type Ia supernova can occur before its parent white dwarf reaches a critical mass.