Roger Smith

A distant lamp shines through uneven glass. The glass bends the rays, and instead of one flame on the wall, several appear — some brighter, some fainter. In much the same way, a massive galaxy bends the light of an exploded star. There was one explosion, but the images show four glowing points.

17 supernovae from the ZTF DR2 sample lit up ahead of schedule. In the first hours and days after the explosion, they emitted more light than standard models predict. Astronomers compare this to a Bickford fuse: before the blinding flash tears across the sky, a precursor spark runs through the outer layers.