A googol is 10 to the 100th power (which is 1 followed by 100 zeros). A googol is larger than the number of elementary particles in the universe, which amount to only 10 to the 80th power.
The term was invented by Milton Sirotta, the 9-year nephew of mathematician Edward Kasner, who had asked his nephew what he thought such a large number should be called. Such a number, Milton apparently replied after a short thought, could only be called something as silly as a "googol."
Later, another mathematician devised the term googolplex for 10 to thepower of googol - that is, 1 followed by 10 to the power of 100 zeros. Frank Pilhofer has determined that, given Moore's Law (which is that computer processor power doubles about every 1 to 2 years), it would make no sense to try to print out a googolplex for another 524 years - since all earlier attempts to print a googolplex out would be overtaken by the faster processor.
