The universe was only two thirds its present age when the light from the galaxies in this image set out on its journey towards Earth. By resolving detail in the images of faint, remote galaxies, HST acts as a 'time machine', allowing astronomers to probe back into the past history of the universe and see galaxies they were then.
The view here shows the central portion of a cluster of galaxies known as CL 0939+4713. Most of the spiral or disk galaxies visible have odd features, suggesting they were easily distorted by the gravitational influence of neighbors within such a 'rich' cluster. There even seem to be a number of mysterious 'fragments' of galaxies interspersed through the cluster.
Looking back billions of years, we can see that galaxy clusters at that time contained several times more spiral galaxies than similar clusters do now. These spiral galaxies have since disappeared through mergers and disruptions.
Camera: WFPC2
Credit: A. Dressler (Carnegie Institution
of Washington), and NASA
