It's a case of cosmic deja vu and another confirmation of Einstein's general theory of relativity.
Four images of the same supernova that exploded over nine billion years ago are delighting astronomers both visually and scientifically.
Astronomers using the Hubble Space Telescope have taken a single image that shows this supernova exploding four different times. The four depictions of one explosion can only be explained by an exotic effect called gravitational lensing. The image is called the "Einstein Cross".
Light rays from the star have been bent and magnified by the gravity of an intervening cluster of galaxies so that multiple images of the supernova explosion appear. Each image in the cross represents a slightly different moment in the supernova explosion because each light ray follows a different path from the star to observers on Earth.
This is the first time astronomers have been able to see the same explosion over and over again, said The New York Times.
"I was sort of astounded," said Patrick Kelly of the University of California, Berkeley, who discovered the supernova images in November 2014. "I was not expecting anything like that at all."
"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", said Robert Kirshner, a supernova expert at the Harvard-Smithsonian Center for Astrophysics .
The Einstein Cross or Q2237+030 or QSO 2237+0305 is a gravitationally lensed quasar directly behind ZW 2237+030, Huchra's Lens. Strong gravitational lensing has caused four images of the same distant quasar to appear around a foreground galaxy.
The quasar is located about nine billion light years from Earth. On the other hand, the lensing galaxy or Huchra's lens is located at a distance of 400 million light years. Huchra's lens is also called ZW 2237+030 or QSO 2237+0305 G.
The Einstein Cross can be found in Pegasus at 22h40m30.3s, +3° 21′ 31″.