Then the scientists divided the «atmospheric» spectrum by the star's «clean» spectrum to determine the gas composition and density of the atmosphere at different altitudes, as well as temperatures. (spaceref.com)
PC 130: The correct version says GE is proportional to the total density of the atmosphere. (realclimate.org)
Titan's gravity, the relative densities of its atmosphere and seas, and the seas» viscosity and surface tension all went into his model. (newscientist.com)