A Gallery of Gravitational Mirages

Explanation: The deeper you peer into the universe, the harder it is to see straight. The reason is that distant galaxies act as gravitational lenses , deflecting light that passes nearby. These deflections result in the distortion of background sources , and in some cases the creation of multiple images . Pictured above , candidate artifacts of gravitational lensing have been found in images from the Medium Deep Survey being done with the Hubble Space Telescope . Background source images that are lensed by foreground galaxies include quasars, appearing as multiple blue smudges , and galaxies, distorted into curving arcs . Unusual and interesting candidates for gravitational lensing include an edge-on galaxy disk which might be acting as a lens (upper left) and an image nicknamed London Underground (far left) which could well be the distortion of a background galaxy into an optical Einstein ring .