Another interesting question: Who says that expansion (or contraction) has not been occurring at differing speeds over the life of the universe? What was the rate a few hundred years ago before we even understood we could measure it? If this is so, then all of Sagan's bets are off.
Really throws a kink in everything, doesn't it?
I know that after drinking multiple glasses of "Midwest Screwdrivers" the Universe seems to speed up and then procede to rotate to the right at an ever increasing rate of speed...
Then I wake up the next morning and it seems the Universe is going at a high rate of speed in reverse (which would explain why my eyeballs feel like they are gonna pop out of my head)