Two models of galaxy formation were being investigated simultaneously on the 1970’s. The bottom-up model was championed by Peebles, and the top-down model by Zeldovich. At first, dark matter was not part of either model, but this effort to explain the origin of galaxies eventually stalled for both models the because the temperature fluctuations in the cosmic background radiation are too small to accommodate galaxy formation from baryons alone. At first massive neutrinos were introduced as dark matter, and when this failed to word, cold dark matter (CDM) was introduced. CDM forms early halos, and then baryons eventually fall into these halos. The first CDM computer models of galaxy formation were introduced by Melott and Shandarin and later developed by the “Gang of Four” (White, Davis, Efstathiou and Frenk). Eventually, the top-down and bottom-up models gracefully merged, and the concept of “biasing” became part of the final model.

Jaan Einasto at first investigated the structure of nearby galaxies and helped to deduce that they are dominated by dark matter. Joeveer at first studied the distribution and dynamics of stars in our Milky Way galaxy. In a joint effort in the mid-1970s, they investigated the galaxy distribution using catalogued data and began to see evidence for large-scale inhomogeneities. A careful review of their investigation reveals shortcomings. The Tartu Observatory 1.5-m telescope was built and commissioned in this era, but it was not equipped with a spectrograph capable of detecting galaxy redshifts. The greatest advantage held by the Estonians came from their early knowledge of computer simulations by Shandarin based on the Zeldovich approximation. At IAU Symposium No. 79 organized by the Estonian astronomers, the first open discussion was held of cosmic voids. Also participating in the meeting was Brent Tully, an expert on the structure of the Local supercluster.