Shown here is supernova Refsdal (four points of light in the spiral arm of a distant background galaxy) multiply lensed by the foreground galaxy cluster MACS J1149. Credit: NASA, ESA, and S. Rodney (JHU) and the FrontierSN team; T. Treu (UCLA), P. Kelly (UC Berkeley), and the GLASS team; J. Lotz (STScI) and the Frontier Fields team; M. Postman (STScI) and the CLASH team; and Z. Levay (STScI)