cosmological distance measures

This morning I met with Gus Beane (Penn) to discuss our work on a possible update of my pedagogical notes on cosmological distance measures. It needs to be updated because the world models in that note are so out of date! (See, for example, footnote 1 on page 2.) And the discussion about what's important doesn't map well onto what's important in today's cosmological context, where the dark energy has internal complexity. We discussed the scope or form for an update and haven't decided whether it is a total re-write, a revision, or an appendix. But whatever we decide, the first order of business is to find out what parameterizations are currently in use for the dark energy, and update all the equations, and figure out which of the analytic results survive the update (very few will, I think). Of course it's hard to predict where things are going in the future, so I don't know what we should really concentrate on.