It looks like the universe is smiling down on us. A recent photograph taken by the Hubble Space Telescope of galaxy cluster SDSS J1038+4849 shows what looks to be a happy face in space, complete with two dots for eyes and what looks to be a smile. The smile and the circular shape of the face is caused by what NASA calls “gravitational lensing”, which is an optical illusion of sorts caused by distortions in space-time.
“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,” NASA said in a statement.
“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.”
Astronomers use “gravitational lensing” to identify massive objects that are otherwise invisible. Examples of these are black holes, galaxy clusters, and dark matter. As it turns out, the happy face in space that was photographed by the Hubble Space Telescope is nothing more than a mere coincidence. But it’s definitely a delightful one.
Albert Einstein first theorized about the bending of light by a gravitational body in 1912, before he made his theory of general relativity. In 1926, the existence of Einstein rings were first mentioned in academic literature by Orest Chwolson. In 1936, Einstein wrote a paper about gravitational lensing saying, “Of course, there is no hope of observing this phenomenon directly. First, we shall scarcely ever approach closely enough to such a central line. Second, the angle β will defy the resolving power of our instruments.”
The first Einstein ring was discovered in 1988 by Hewitt, et al., after observing the radio source MG1131+0456 using the Very Large Array.
The “happy face in space” wasn’t the first Einstein ring photographed by the Hubble Space Telescope, it’s just one among many. In fact, the Hubble Space Telescope was even able to photograph the existence of a double Einstein ring. The image shows a galaxy surrounded by an almost complete ring with a fainter ring around it, making it look like a bull’s eye in a dartboard.
[Image via YouTube]