We begin with the concept of a billion. One billion is represented as a one followed by nine zeros (1,000,000,000); it is one thousand times the size of one million (represented as a one followed by six zeroes—1,000,000). But what does one thousand times greater than one million really mean? Mathematician John Allen Paulos, author of Innumeracy, a book about overcoming ignorance of mathematics and a fear of numbers, presents this example. It takes eleven and one half days for one million seconds to elapse. Can you guess how long it takes for one billion seconds to tick away? Try thirty-two years.

If those numbers impress you, you may be willing to follow our advice not to leave your grandchildren a time capsule with instructions to open it in one trillion seconds. That's because it will take 31,709 years—that's one-thousand billion seconds—to go by.