Artist’s impression of two white dwarf stars destined to merge and create a Type Ia supernova. Credit: ESO/L. Calçada Astronomers can see into the future of the two superdense stars racing around the center of planetary nebula Henize 2-428. And it doesn’t look good. Their racetrack is slowly (but steadily) shrinking. And in 700 million years, they will crash into each other, igniting a Type Ia supernova. In over a century of astronomers studying supernovae, this is the first time they’ve seen this type of supernova in the making.