Titan's atmosphere, per this NewScientist article, is ten times denser than Earth's, though the moon is less than half Earth's size. The composition is largely nitrogen, like ours, with a small component of methane, so chemical density should be similar, if gravity were same, actually less (except for temperature differences).
How can this be, unless Newton's G is greater there than here? My calculations (as discussed at length on these pages) shows G should be at about 10 times Earth's G, since Saturn is about 9.5 AU vs. Earth's 1 AU. If G grows in linear proportion to distance from the Sun, then it all fits. Awaiting more good news... Thanks Titan!
BTW, compare this atmosphere to Gynamede's, a Jovian moon slightly larger than Titan with only a whisp of atmosphere, and this Titan atmopshere density becomes a real conundrum. Jupiter at about 5.2 AU should show G about five times Earth's G. At this point, only Jerry and I seem to think this way... to the power of 2?