How are galaxies distributed in space ?
Galaxies are not distributed evenly through space. As we have seen, a big galaxy may have satellite galaxies. On a larger scale, galaxies come in clusters. For example there is a small “Local Cluster” containing our Galaxy and the Andromeda galaxy plus several others (mostly small). An example of a big cluster of galaxies is the Virgo Cluster. One can look on a larger scale. Margaret Geller of Harvard has done the following. • Choose a thin slice of sky. • The idea is to examine everything in that slice out to a certain distance. • Viewed from above, the region examined then looks like a slice from a very thin pie. • Measure the angles to all the galaxies in that slice. • “Measure” the distances to the galaxies by measuring the redshifts and assuming the Hubble relation. • Plot the points. Here is my impression of the results. The real data is in Fig26-23 of your book. Unfortunately, I couldn’t find an electronic version. The thing one notices is not so much the clusters of galaxie
