NASA, ESA, and T. Treu (UCLA), P. Kelly (UC Berkeley) and the GLASS team; S. Rodney (JHU) and the FrontierSN team; J. Lotz (STScI) and the Frontier Fields Team; M. Postman (STScI), and the CLASH team; and Z. Levay (STScI)
The Hubble Space Telescope is seeing quadruple. Four images of the same supernova flashed in the constellation Leo as its light bent around a galaxy sitting about 6 billion light-years away between Hubble and the exploding star, researchers report in the March 6 Science.
The light from the supernova, nicknamed Refsdal, traveled for over 9 billion years along paths dictated by the gravity of the intervening galaxy. By measuring how the light bent, astronomers can measure the galaxy’s mass. Researchers also hope to use the multiple images to estimate the Hubble constant, a measure how fast the universe is expanding.