Say cheese! The Hubble Space Telescope captured this friendly image of the galaxy cluster SDSS J1038+4849 in the constellation Ursa Major.
The eyes of this galactic happy face are two distant, bright galaxies, according to an ESA release, and lines that make up the face and smile are actually arcs created by an effect called strong gravitational lensing. Galaxy clusters are some of the universe’s most massive structures, capable of exerting a gravitational pull so strong, it warps the spacetime around them. By redirecting light rays, a galaxy cluster in the foreground acts as a cosmic lens that can magnify, distort, and bend the light that’s behind them. In this particular case, the bending of light from some faraway source produced a ring-like structure called an Einstein Ring: the result of an exact, symmetrical alignment of the light source, the lens, and the observer.
Gravitational lensing is important to many of Hubble’s discoveries, including sneak peaks into the Early Universe. This smiley object was studied as part of a survey of strong lenses using Hubble’s Wide Field and Planetary Camera 2 and Wide Field Camera 3. A version of this image was entered into the Hubble’s Hidden Treasures 2012 Image Processing Contest by Judy Schmidt. Hubble has made more than a million observations since 1990, resulting in vast archive. Contestants in this competition had to process previously unpublished images with astronomical image software used by ESA and NASA. You can see more entries on their Flickr page.