2015-03-05. Astronomers Watch a Supernova and See Reruns.

posted Mar 8, 2015, 2:29 PM by Alan Gould   [ updated Mar 8, 2015, 2:30 PM ]
By Dennis Overbye, The New York Times. For GSS A Changing Cosmos chapter 6. Excerpt: ...astronomers using the Hubble Space Telescope say they have been watching the same star blow itself to smithereens in a supernova explosion over and over again, thanks to a trick of Einsteinian optics. The star exploded more than nine billion years ago on the other side of the universe, too far for even the Hubble to see without special help from the cosmos. ...light rays from the star have been bent and magnified by the gravity of an intervening cluster of galaxies so that multiple images of it appear. Four of them are arranged in a tight formation known as an Einstein Cross surrounding one of the galaxies in the cluster.  ...This is the first time astronomers have been able to see the same explosion over and over again, and its unique properties may help them better understand not only the nature of these spectacular phenomena but also cosmological mysteries like dark matter and how fast the universe is expanding.... “I was sort of astounded,” said Patrick Kelly of the University of California, Berkeley, who discovered the supernova images in data recorded by the space telescope in November ...lead author of a report describing the supernova published on Thursday in the journal Science. ...Robert Kirshner, a supernova expert at the Harvard-Smithsonian Center for Astrophysics who was not involved in the work, said: “We’ve seen gravitational lenses before, and we’ve seen supernovae before. We’ve even seen lensed supernovae before. But this multiple image is what we have all been hoping to see.”.... http://www.nytimes.com/2015/03/06/science/astronomers-observe-supernova-and-find-theyre-watching-reruns.html.