Rare supernova discovery ushers in new era for cosmology

With the help of an automated supernova-hunting pipeline and a galaxy sitting 2 bil-lion light years away from Earth that’s acting as a “magnifying glass,” astronomers have captured multiple images of a Type Ia supernova—the brilliant explosion of a star—appearing in four different locations on the sky. So far this is the only Type Ia discovered that has exhibited this effect.