The universe it seems is not without a sense of humor. At least that’s one conclusion a person might draw from this very real image of a distant galaxy cluster bent by the gravity of a nearer cluster into a cosmic smiley face:
Galaxy clusters are the most massive structures in the Universe and exert such a powerful gravitational pull that they warp the spacetime around them and act as cosmic lenses which can magnify, distort and bend the light behind them. This phenomenon, crucial to many of Hubble’s discoveries, can be explained by Einstein’s theory of general relativity.
In this special case of gravitational lensing, a ring — known as an Einstein Ring — is produced from this bending of light, a consequence of the exact and symmetrical alignment of the source, lens and observer and resulting in the ring-like structure we see here.
It’s too bad we didn’t have the Hubble or something like it a hundred years ago. It would have saved a number of people chasing total eclipses all over the world, with bulky telescopes and other gear in hand, to confirm or reject one of the more spectacular predictions of Einstein’s theory of general relativity, first published exactly 100 years ago: the eerie bending of space-time by sheer mass and gravity.