Figure 25-22: Structure Evolution from Sound Waves This illustration shows the evolution of early density variations seen in the CMB to the present-day distribution of galaxies. The size scales of the resulting variations are much larger than galaxies or clusters, and the variations show up as filaments and voids traced out by the distribution of superclusters of galaxies. The Baryon Oscillation Spectroscopic Survey (BOSS) has observed these variations at their predicted size scale of around 150 Mpc.

(Illustration courtesy of Chris Blake and Sam Moorfield)