A recent stellar explosion in a nearby galaxy gave astronomers a rare glimpse into the early stages of a supernova. Supernova PTF 11kly is only 21 million light-years from Earth—the closest Type Ia supernova in a generation. Type Ia supernovas are used to measure cosmic distances; astronomers are hailing this one as an "instant cosmic classic." The latest Astro Bulletin from the Museum's Science Bulletins program highlights this singular supernova in progress. View the story in AMNH's Hall of the Universe until November 25, 2011 or online.