These elliptical and spiral galaxies look as though they were scattered; in fact, they are all part of the nearby Centaurus Cluster, a very loose collection of galaxies, about 30 times less dense than the rich Perseus Cluster. 
    The galaxies in a cluster are gravitationally bound to each other. None of those seen here is likely ever to leave the cluster. Even if a galaxy’s path were to take it away from the cluster, the combined gravity of the other galaxies in the cluster would prevent its escape.