A gravitational lens system has been discovered by undergraduate students examining images from the 8.2-metre Subaru Telescope’s Hyper Suprime-Cam. Dubbed the “Eye of Horus” due to the system’s uncanny resemblance to the sacred eye of the ancient Egyptian goddess, it is formed by a galaxy 7 billion light-years from the Earth bending the light from two more galaxies directly behind it.
Dark matter is a mysterious substance composing most of the material universe, now widely thought to be some form of massive exotic particle. An intriguing alternative view is that dark matter is made of black holes formed during the first second of our universe’s existence, known as primordial black holes.
Subtle distortions hidden in a stunning Atacama Large Millimetre/submillimetre Array (ALMA) image of the gravitational lens SDP.81 are telltale signs that a dwarf dark galaxy is lurking in the halo of a much larger galaxy nearly 4 billion light-years away. This discovery could help astronomers address important questions on the nature of dark matter.