Astronomers traced one of the weirder twists in relativity to determine when they’d see an “instant replay” of a distant supernova, and now the Hubble Space Telescope has shown that their prediction was right. They say it marks the first time a supernova observation was predicted in advance.
The confirmation comes in the form of Hubble’s observations of the galaxy cluster MACS J1149.5+2223 over the course of more than a year. When scientists studied pictures taken in November 2014, they identified a supernova flash that had beensplit into four separate images, due to the cluster’s gravitational lensing effect.
