Marcus Chown writing in this week's New Scientist [subscribers only link] about the so-called Goldilocks Paradox (i.e. why do the laws of physics seem fine-tuned for life?):
The most likely explanation for fine-tuning is […] that our universe is merely one of a vast ensemble of universes, each with different laws of physics. We find ourselves in one with laws suitable for life because, again, how could it be any other way?
The multiverse idea is not without theoretical backing. String theory, our best attempt yet at a theory of everything, predicts at least 10500 universes, each with different laws of physics. To put that number into perspective, there are an estimated 1025 grains of sand in the Sahara desert.
I don't think that puts it into perspective at all. Do you? What Chown is saying is that the number of grains of sand in the Sahara is 10475 times smaller than the theoretically predicted minimum number of universes in the multiverse (10500 ÷ 1025 = 10475).
I don't think 10475 is much easier to envisage than 10500. That's a 1 followed by 475 zeroes, as opposed to a 1 followed by 500 zeroes.
Chown might almost as well have said, "To put that number into perspective, I only have two legs". Two is much closer to 1025 than 1025 is to 10500. Several hundreds of orders of magnitude closer, in fact.
In other words, as I'm sure Chown would agree, 10500 is an unimaginably vast number. You can't really put it into any sort of perspective.
Nice try, though, Mr Chown: you certainly got me thinking.