New evidence that some supernovae may be a “double detonation”

Astronomers have discovered evidence of "double detonation" supernovae, where a small explosion on a white dwarf's surface can trigger a full supernova before the star reaches critical mass. This finding challenges assumptions about type Ia supernovae, which are used to measure cosmic distances. The discovery, based on observations of supernova remnant SNR 0509-67.5, could impact our understanding of the universe's expansion and dark energy.