Einstein ring
An Einstein ring is a phenomenon where the light from a distant object, such as a galaxy or quasar, is bent into a ring shape by the gravitational field of a massive foreground object, like another galaxy. This effect is a consequence of Einstein's theory of general relativity.
Source: hyperphysics.phy-astr.gsu.edu
APODs including "Einstein ring"
A Big Dish at the VLA Radio Observatory
29/11/2006
They are so large, they are almost unreal. The radio dishes of the Very Large Array (VLA) of radio telescopes might appear to some as a strange combination of a dinosaur skeleton and common satellite-TV receiving dish. Together, the 27 dishes of the VLA combine high sensitivity with high resolution, enabling a series of important astronomical discoveries, including water ice on planet Mercury, micro-quasars in our Galaxy, gravitationally-induced Einstein rings around distant galaxies, and radio counterparts to cosmologically distant gamma-ray bursts. Pictured above, a dish from the VLA was photographed last week near Socorro, New Mexico, USA.