Space warp puts a supernova on cosmic repeat

An intergalactic mirage of sorts is acting like a time machine for astronomers, allowing them to see a supernova at three different stages in the explosion simultaneously. And it’s going to allow them to see it again in a kind of cosmic rerun.

About 4 billion light years from Earth lies the magnificent galaxy cluster MACSJ0138.0-2155 (let’s call it MACS J0138 for short). This is a collection of hundreds of galaxies all bound together by their mutual gravity. The mass of the cluster is so strong...