Image List

The thin blue bull's-eye patterns in these six Hubble Space Telescope images are so-called "Einstein rings," which are the most elegant manifestation of gravitational lensing. The yellowish-red blobs are giant elliptical galaxies roughly 2 to 4 billion light-years away. Einstein rings are created as the light from galaxies twice as far away is distorted into circular shapes by the gravity of the intervening giant elliptical galaxies. Gravitational lensing allows astronomers to study the distribution of unseen matter in the lensing galaxies, and to observe light from more distant galaxies that would otherwise remain undetectably faint.