Question

Let’s say there are 4000 galaxies within a 2.5 Mpc diameter spherical volume of the Coma Cluster and that there are 12000 galaxies within a 60 Mpc diameter spherical volume com- prising the Bootes Void. What is the ratio of the galaxy density of the cluster and the galaxy density in the void? Calculate the ratio of the densities of titanium and air (look these up) and compare to the result for the cluster/void density ratio. By what factor is the tita- nium/air density ratio bigger or smaller than the cluster/void density ratio?

Answer 1