When nine-year-old Milton Sirotta’s uncle asked him to come up with a name for a number that had a hundred zeros after it, he left oodles of possible words ending in “-illion” behind, and coined the word “Googol.” In case you’re wondering, the number looks like this:

10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000.

A googol is a number bigger than the number of bugs’ legs on the earth. It’s even bigger than all the pixels contained in the webpages on, well, Google.

It’s not every nine year old that gets to name something so mind-boggling huge. He decided to go one step further, and suggested the googolplex — a number that had as many zeroes as you could write, until you were simply too tired to write anymore.

His wise uncle Edward thought the definition required some refinement.

They finally agreed that a googolplex was a number with a googol of zeros behind it. If you actually tried to write all those zeros, each the size of a period, you’d make it all the way to the edge of the known universe and still not be finished. Milton might have pointed out that by that time your hand might indeed be a bit fatigued.

Edward Kasner, a math instructor from Colombia University, first published these words in 1940 in his book MATHEMATICS AND THE IMAGINATION.

http://en.wikipedia.org/wiki/Names_of_large_numbers