# Googol

A googol is the large number 10100; that is, the digit 1 followed by 100 zeroes:

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

The term was coined in 1938[1] by 9-year-old Milton Sirotta, nephew of American mathematician Edward Kasner. Kasner popularized the concept in his 1940 book Mathematics and the Imagination.

Other names for googol include ten duotrigintillion on the short scale, ten thousand sexdecillion on the long scale, or ten sexdecilliard on the Peletier long scale. A googol has no particular significance in mathematics, but is useful when comparing with other very large quantities such as the number of subatomic particles in the visible universe or the number of hypothetical possibilities in a chess game. Edward Kasner used it to illustrate the difference between an unimaginably large number and infinity, and in this role it is sometimes used in teaching mathematics.

A googol is approximately 70! (factorial of 70). In the binary numeral system, one would need 333 bits to represent a googol, i.e., 1 googol ≈ 2332.2, or exactly $2^{(100/\mathrm{log}_{10}2)}$.

Googol is notable for being the subject of the £1 million question in the infamous episode of Who Wants to Be a Millionaire?, when contestant Charles Ingram cheated his way through the show by getting help from fellow contestant Tecwen Whittock.

Widespread sounding of the word occurs through its namesake of the famous internet company Google, with the name "Google" being a misspelling of "googol" by the company's founders,[2] which was picked to signify that the search engine was intended to provide large quantities of information.[3]

To give a sense of how big a googol really is, the mass of an electron, just under 1×10-30 kg, can be compared to the mass of the visible universe, estimated at between 1×1050kg and 1×1060 kg.[4] It is a ratio in the order of about 1080 to 1090, still much smaller than the value of a googol.