For the first time ever, scientists have captured the image of an exploding star — one they correctly predicted would do so ahead of time.
Supernova Refsdal, as the star was named, was first noticed by astronomers from NASA and ESA back in 2014 when it appeared in four different images in an Einstein's Cross formation, AKA a gravitationally-lensed quasar, all of it due to forces deployed by a galaxy cluster known as MACS J1149.5+2223. Because of the way light reaches us from space — and the amount of distance it has to travel to do so — the explosion the astronomers caught on camera actually occurred roughly 10 billion years ago and took about half that time to get within our (galactic) line of vision.
"While studying the supernova, we realized that the galaxy in which it exploded is already known to be a galaxy that is being lensed by the cluster," said Steve Rodney from the University of South Carolina, one of the study's lead astronomers, in an official statement released on the Hubble Telescope's site. "The supernova's host galaxy appears to us in at least three distinct images caused by the warping mass of the galaxy cluster." This means, more or less, that the scientists were able to view this phenomenon three times previously due to the gravitational force of the cluster, which is powerful enough to actually bend space-time.
This arrangement magnified the galaxy cluster (see photos above), in what otherwise should have blocked us from viewing the supernova in the first place.
Tommaso Treu, an astronomer at the University of California, elaborated on how the scientists were able to correctly predict when the sight of the star explosion would reach us.
"We used seven different models of the [galaxy] cluster to calculate when and where the supernova was going to appear in the future," explained Treu. "It was a huge effort from the community to gather the necessary input data using Hubble, VLT-MUSE, and Keck and to construct the lens models."
Luckily, each respective model estimated that the image of Refsdal would appear around the same time (or at least within the same time frame); the actual occurrence transpired on Dec. 11 of this year.
Via: Gizmodo
