A googolplex is a very large number defined as 10 raised to the power of a googol. A googol itself is 10 raised to the power of 100, which means it is a 1 followed by 100 zeros. Therefore, a googolplex is 1 followed by a googol of zeros, making it an unimaginably large number. To put this in perspective, if you tried to write out a googolplex in standard form, it would be impossible to fit it on the entire observable universe, as there simply isn't enough space to accommodate all those zeros. The concept of a googolplex was introduced by mathematician Edward Kasner in the early 20th century.