42 is the answer to Life, the Universe and Everything, as given by a supercomputer to a group of mice in Douglas_Adams's The Hitch Hikers Guide to the Galaxy. According to the Guide - Mice are the most intelligent life in the universe. That is why they live in the labratories where they can study mankind's greatest minds at work. They build a computer to tell them the answer to life, the universe and everything. After 10,000 years the computer divulges the answer - 42.
"Ah But what is the question?" "That will take another computer and another 10,000 years to answer." replies the supercomouter.
Earth is that second computer.
Some theories proposed about the possible question:
- "What is 6 times 9?" - This theory only works if the calculations are done in base 13 (not base 10.) Douglas Adams was not aware of this at the time, and has denied that "6 times 9" is the true question.
- It was also proposed in the book that perhaps the question is "How many roads must a man walk down?"