[0910.1589] How many universes are in the multiverse?

Alert: spoiler ahead. First you have to get beyond the abstract and 10 pages of dense material. The answer is 10^10^10^7, which is a pretty big number, even bigger that the 10^500 from string theory. Then they start applying simplifications, like the number of distinct universes, and the number that are observable locally. It is still a pretty big number.

If I apply their criteria that the universes be locally observable, I get a much smaller number. Our universe is probably much larger than the observable universe, so I get > 1.

Fooey, I was hoping to grab my laptop and a copy of the PDR, jump backwards 30 years, marry the other girl, and become filthy rich. These cosmologists just have to try a little harder.

Two - and the other one is exactly like us, except they all have cowboy hats.