This brand new picture from Hubble is as interesting as it is beautiful. This double quasar was first discovered back in 1979 and they share some incredible properties. The objects are very close to each other, they are both the same distance away from us (about 14-billion light-years away), they are extremely similar to each other. This raised some red flags because, when I say they are similar, I mean they are basically identical twins. It turns out, these two quasars aren't identical twins, but they are actually the same quasar. Obviously, the question is raised "if it's the same quasar, why do we see it twice?"
Obviously, we broke physics... or, maybe there is another explanation.
About 4-billion light-years from us, there is an utterly massive galaxy that is directly in between Earth and the Double Quasar. This galaxy, called YGKOW G1, warps spacetime causing a significant amount of gravitational lensing, especially if something is lined up just right. Gravitational lensing can cause a number of optical illusions and this is one of them.
When astronomers first realized that the Double Quasar was made of two nearly identical objects, they investigated the situation further and realized that this lensing was occurring. This was the first time that such a phenomenon was observed and it validated general relativity and the prediction of gravitational lensing (which was first proposed in 1936).