p12
Is 10^10 big?
H Nakanishi pointed out that the world human population is of order 10^9, so 10^10 is a rather `familiar’ number, not astronomical (or perhaps we should say our population is astronomically abnormal).
We human-beings are made of 1014 cells of our own and about the same number of (or about one or two orders more of) prokaryote cells.