Credit: H. Ford (JHU), W. Zheng (JHU), L. Infante (PUC), V. Motta(PUC, JHU), M. Postman (STScI), G. Illingworth (UCSC), M. Jee (JHU), R. White (STScI), N. Benitez (IAA), T. Broadhurst (Tel-Aviv Univ.), and NASA
(The figure shows a three-color image of the massive cluster of galaxies Abell 2218 taken with the Advanced Camera for Surveys in the Hubble Space Telescope. The distance to the cluster is approximately 2.5 billion light years. The blue arcs are star-forming galaxies that are behind the cluster approximately halfway across the universe. This is a beautiful example of a "cosmic telescope."