  There are (at least) four numbers of physical and cosmological significance
whose inferred values, when expressed in mass units, cluster in a window below
1 eV. These are: the neutrino mass, the neutrino chemical potential, the
cosmological constant, and the size of two extra dimensions (if the fundamental
scale of gravity is 1-10 TeV). In this note, we imagine ways in which these
four numbers could all be connected.
