Image 19:   Abell 1689: A Rich Cluster of Galaxies

This is one of the densest locations in our Universe - a region a few million light years across just crammed with several thousand galaxies. Notice that almost all the galaxies are old, yellow, ellipticals. That's because the young blue disks of spiral galaxies are fragile things that can't survive a the rough ride of gravitational "jolts" as they zoom through the cluster passing close to other galaxies. This is really quite a chaotic environment - not one that nurtures the gentle majesty of an orderly rotating disk of gas and stars.

Although this galaxy cluster lies 2.5 billion light years away, the exquisitely sharp vision of the Hubble Space Telescope reveals many extremely distant galaxies that lie well behind the cluster. The remarkable fact is that the huge gravitational field from all the matter in this cluster acts like a giant lens, bending the light rays and magnifying the galaxies behind the lens. Because the lens is rather lumpy, the background galaxies appear rather distorted and many are stretched into thin arcs. A careful analysis of the lens reveals special regions with much higher magnification, near 30 times, so that the Hubble Telescope's 2.5 meter mirror is effectively boosted to a 10 meter mirror! Using the combined power of this natural telescope, some of the most distant galaxies yet known have been found, including a record breaking object at 13.0 billion light years, only 700 million years after the Big Bang. At these enormous "look-back times", the Universe contains only infant galaxies: small and chaotic collections of stars looking nothing like the huge stately giants we see all around us today. In fact, it takes another 5 billion years before galaxies like the Milky Way begin to appear in the cosmic record, gradually assembled by the gravitational coalescence of hundreds of these tiny infants.

But what about earlier times? Can we see back to the Universe's actual birth? The answer is yes, and that's what the final image in our series shows.