A Rare Quadruple Supernova, Revealed by a Quirk of Einstein
By William Herkewitz
Apr 20, 2017
The star had been in hiding. A galaxy sat halfway between it and us, eclipsing it from the Earth's point of view. But when it went supernova last September, astronomers caught the image of the concealed explosion anyhow, all thanks to a cool trick of physics.
Because of a bizarre effect called gravitational lensing explained by Einstein's theory of general relativity, scientists caught four separate images of the supernova in a single picture. Stranger still, the faraway supernova—it lies more than 4.4 billion light years from home—was naturally magnified by 5,000 percent when the scientists first saw it.
http://www.popularmechanics.com/space/deep-space/news/a26164/quadruple-supernova/