Figure 8: The temporal dependence of energy rate density for human society as plotted here pertains only to the topmost part of the master graph in Figure 2 and thus concerns less than the past million years or <0.01% of all of cosmic history. This graph serves to illustrate the advance of (per capita) energy usage by some of our hominid ancestral groups during the cultural-evolutionary phase of cosmic evolution. On a linear temporal scale as plotted here, that rise is approximately exponential in very recent times as civilization has become heavily dependent upon energy for its continued well-being.