This small galaxy cluster, in the constellation Pisces, contains about a hundred galaxies. The Pisces Cluster is roughly the same distance from Earth as the Perseus Cluster; both belong to the fila- mentary Perseus-Pisces Super- cluster.
In addition to superclusters, the universe contains voids:
unimaginably wide spaces where there are few galaxies. Just beyond the Perseus-Pisces supercluster, for example, there is a large void containing only a handful of bright galaxies.
The early universe was uniform, with only very small deviations in consistency. The COBE satellite (Cosmic Background Explorer) has measured the universeΓÇÖs micro-
