This just in: systems with broadly similar characteristics behave in roughly the same fashion. In this case, mosh pits seem to look a lot like gasses in "2D equilibrium." No, I'm not completely sure what that is, either. What it mostly proves is I'm old enough to be puzzled by the "heavy metal = mosh pit" assumption. All my metal gods are old enough now to get put in a hospital by such shenanigans.