November 17, 2005: Astronomers have combined two powerful astronomical assets, the Sloan Digital Sky Survey (SDSS) and NASA's Hubble Space Telescope, to identify 19 new "gravitationally lensed" galaxies, adding significantly to the approximately 100 gravitational lenses previously known. Among these 19, they have found eight new so-called "Einstein rings," which are perhaps the most elegant manifestation of the lensing phenomenon. Gravitational lensing occurs when the gravitational field from a massive object warps space and deflects light from a distant object behind it. Einstein rings are produced when two galaxies are almost perfectly aligned, one behind the other.
The thin blue bull's-eye patterns in these eight Hubble Space Telescope images appear like neon signs floating over reddish-white blobs. The blobs are giant elliptical galaxies roughly 2 to 4 billion light-years away. The bull's-eye patterns are Einstein rings, which are created as the light from galaxies twice as far away is distorted into circular shapes by the gravity of the giant elliptical galaxies.See the rest: