Galaxy zoom

13 May 2013 - Bright arcs are smeared around the heart of galaxy cluster Abell S1077 in this image taken by the NASA/ESA Hubble space telescope. The arcs are stretched images of distant galaxies distorted by the cluster's enormous gravitational field. Galaxy clusters are large groupings of galaxies, each hosting millions of stars. They are the largest existing structures in the Universe, bound by the gravitational attraction between them. The amount of matter condensed in such groupings is so high that their gravity is enough to warp even the fabric of space-time, distorting the path that light takes when it travels through the cluster. In some cases, this phenomenon produces an effect somewhat like a magnifying lens, allowing us to see objects that are aligned behind the cluster and that would otherwise be undetectable from Earth. In this image, stretched stripes that look like scratches on a lens are in fact galaxies whose light is heavily distorted by the gravitational field of the cluster.