A 50-year-old theory has been proven true as astronomers have come across a startling image from the Hubble Telescope: one supernova, appearing in four different places in a cross or diamond pattern around a distant galaxy.

The remarkable image is due to an effect called gravitational or cosmic lensing. The cross configuration is referred to as an “Einstein cross,” in honor of the famous physicist who first predicted how such a seemingly impossible thing could come to pass. Einstein reasoned that the presence of a large enough amount of mass would cause light to bend while passing the object – in much the same way as high-mass objects like planets bend gravity. In 1964, Norwegian astronomer Sjur Refsdal theorized that such a phenomenon could be observed by studying time-delayed images from a lensed supernova, which could in turn yield insights about dark matter and the expansion of the universe.

Now, Refsdal’s theory is being put to the test. Dr. Patrick Kelly of the University of California, Berkeley, noticed the four identical supernovas while studying an image of a cluster of galaxies. Astronomers have hypothesized that dark matter in the dense, compacted galaxy cluster caused the light to bend enough to create the illusion of four exploding stars surrounding a large galaxy near the center.

Dark matter is difficult to study because it cannot be seen directly. However, it is believed to make up the majority of the universe’s mass. Scientists hope that this discovery will better help them understand the way that dark clumps together in the far-away galaxy. It may even lead to a better estimation of the amount and distribution of dark matter throughout the universe.

“Basically, we get to see the supernova four times and measure the time delays between its arrival in the different images, hopefully learning something about the supernova and the kind of star it exploded from, as well as about the gravitational lenses,” said Kelly.