Giant Cluster Bends, Breaks Galaxy Images . ... Credit Copyright: W.N. Colley E. Turner ( Princeton ), J.A. Tyson ( Lucent Technologies ), HST , NASA Explanation: What are those strange blue objects? Many are images of a single, unusual, beaded, blue, ring-like galaxy which just happens to line-up behind a giant cluster of galaxies. Cluster galaxies here appear yellow and -- together with the cluster's dark matter -- act as a gravitational lens . ... NASA Official: Jay Norris. ...