A Supernova explosion over & over

Over nine billion years ago a star exploded on the other side of the universe causing a supernova.  Supernovas are some of the most violent and rare events in the universe that only occur once a century in a typical galaxy.  They are very bright and can outshine other galaxies, spitting out elemental particles into space to form the foundations of new worlds.  They can leave behind neutron stars or black holes.   This particular Supernova is called Refsdal and is more unique than any other supernova; it’s been seen exploding four different times!

Thanks to a trick of Einsteinian optics light from the explosion is curved around a cluster of galaxies.  The tight cluster of four galaxies allows for the light from the exploding star to bend and magnify.  As the light travels around the cluster of galaxies the supernova appears multiple times.   The supernova has been spotted with the Hubble Space Telescope since the 1960’s.  This is the first time astronomers have been able to see the same explosion over and over.

Looking ahead, scientists are anticipating the next appearance of the supernova in the next decade.   With its next appearance, astronomers may be able to determine some long standing scientific questions.  As the next image appears in a different part of the sky, astronomers will measure the distance the image moved and the time it took to get there.   They can then possible figure out what dark matter is and how fast the universe is expanding.