Large numbers, like the U.S. national debt in pennies (~1015), are hard for our brains to deal with.
Consider this true story:
A very distinguished chemist, who had made important biological contributions and was well aware of their importance, was at Yale some years ago to collect a prize. During his lecture he was impressing on us the stupendous variety available to Nature.
He took as an example the number of different polypeptides available by linking together a short chain using the twenty common amino acids. If you have 20 possibilities for each of N positions, there are 20N possible variations (20 possibilities for the first amino acid, 20 for the second, and so on).
"So even if N is only 16," he said, "the number of possible polypeptides is 2016, a number as large as the number of atoms in the universe."
What do you think of this statement?