"It is like a perfect bullseye, being much more difficult than anywhere further from the center of the target," Goobar said.
The arrangement raises questions about whether there's some reason such an intense amplification is more likely than thought, and the structures within the galaxy, like black holes or a dense network of stars, that enhance the lens effect. It also provides a rare opportunity to learn more about the way lenses bend light and the way space-time might have been warped along the paths those light beams traveled, Goobar said.
"Since the various images follow different paths, there is no reason for them to reach us at the same time," Goobar said. Because the type of supernova and the light it gives off is so well-understood, "we can then compare the light curves for the four images and try to estimate the time difference between them, which encodes information on the scale of the universe.
"This information is very precious since it can be used to measure the expansion rate of the universe, i.e. the Hubble Constant," Goobar added. "As we are about to upgrade the surveying capability at Palomar and make it 10 times more efficient, we are very hopeful that we will be finding new, similar systems in the coming years, which bodes well for the prospects of improving the measurement of the expansion rate of the universe."