In the first novel and radio series, a group of hyper-intelligent pan-dimensional beings demand to learn the Answer to the Ultimate Question of Life, the Universe, and Everything from the supercomputer, Deep Thought, specially built for this purpose. It takes Deep Thought 7½ million years to compute and check the answer, which turns out to be 42. Unfortunately, The Ultimate Question itself is unknown.
When asked to produce The Ultimate Question, the computer says that it cannot; however, it can help to design an even more powerful computer (the Earth), that can. The programmers then embark on a further ten-million-year program to discover The Ultimate Question. This new computer will incorporate living beings in the "computational matrix", with the pan-dimensional creators assuming the form of mice. The process is hindered after eight million years by the unexpected arrival on Earth of the Golgafrinchans and then is ruined completely, five minutes before completion, when the Earth is destroyed by the Vogons to make way for a new Hyperspace Bypass. This is later revealed to have been a ruse: the Vogons had been hired to destroy the Earth by a consortium of psychiatrists, led by Gag Halfrunt, who feared for the loss of their careers when the meaning of life became known.
Lacking a real question, the mice decide not to go through the whole thing again and settle for the out-of-thin-air suggestion "How many roads must a man walk down?" from Bob Dylan's protest song "Blowin' in the Wind".
At the end of the first radio series (and television series, as well as The Restaurant at the End of the Universe book) Arthur Dent, having escaped the Earth's destruction, potentially has some of the computational matrix in his brain. He attempts to discover The Ultimate Question by extracting it from his brainwave patterns, as abusively suggested by Marvin the Paranoid Android, when a Scrabble-playing caveman spells out forty two. Arthur pulls random letters from a bag, but only gets the sentence "What do you get if you multiply six by nine?"
| “ | "Six by nine. Forty two."
"That's it. That's all there is." "I always thought something was fundamentally wrong with the universe" |
” |
This 'question' is impossible with a standard set of Scrabble, which contains only two Ys, instead of four (unless you count the two blank tiles). In the television series and book,the set has been handmade from Arthur's memory; in the radio series Arthur has a "pocket Scrabble set" at Milliways.
Six by nine is, of course, fifty-four. The program on the "Earth computer" should have run correctly, but the unexpected arrival of the Golgafrinchans on prehistoric Earth caused input errors into the system—computing (because of the garbage in, garbage out rule) the wrong question—the question in Arthur's subconscious being invalid all along.
Quoting Fit the Seventh of the radio series, on Christmas Eve, 1978:{|align="center" class="cquote2" style="border-style: none; border-collapse: collapse; background-color: transparent;" |valign="top" width="20" style="padding: 10px; color: rgb(178, 183, 242); font-size: 40px; font-family: serif; font-weight: bold; text-align: left;"|“ |valign="top" style="padding: 4px 10px;"|Narrator: There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened. |valign="bottom" width="20" style="padding: 10px; color: rgb(178, 183, 242); font-size: 40px; font-family: serif; font-weight: bold; text-align: right;"|” |} Some readers subsequently noticed that 6 × 9 = 42 (using base 13). Douglas Adams later joked about this observation, saying, "I may be a sorry case, but I don't write jokes in base 13."
In Life, the Universe and Everything, Prak, a man who knows all that is true, confirms that 42 is indeed The Ultimate Answer, and confirms that it is impossible for both The Ultimate Answer and The Ultimate Question to be known about in the same universe (compare the uncertainty principle) as they will cancel each other out and take the Universe with them to be replaced by something even more bizarre (as described in the first theory) and that it may have already happened (as described in the second).Though the question is never found, it is notable that 42 is the table number at which Arthur and his friends sit when they arrive at Milliways at the end of the radio series. Likewise Mostly Harmless, and the book series proper, ends when Arthur stops at a street address identified by his cry of "There, number 42!" and enters the club Beta, owned by Stavro Mueller, who is apparently the final incarnation of Agrajag.
Douglas Adams was asked many times during his career why he chose the number 42. Many theories were proposed,but he rejected them all. On , he gave an answer on alt.fan.douglas-adams:
| “ | The answer to this is very simple. It was a joke. It had to be a number, an ordinary, smallish number, and I chose that one. Binary representations, base thirteen, Tibetan monks are all complete nonsense. I sat at my desk, stared into the garden and thought '42 will do.' I typed it out. End of story. | ” |
Adams described his choice as "A completely ordinary number, a number not just divisible by two but also six and seven. In fact it's the sort of number that you could, without any fear, introduce to your parents."
While 42 was a number with no hidden meaning, Adams explained in more detail in an interview with Iain Johnstone of BBC Radio 4 (recorded in 1998 though never broadcast) to celebrate the first radio broadcast's 20th anniversary. Having decided it should be a number, he tried to think what an "ordinary number" should be. He ruled out non-integers, then he remembered having worked as a "prop-borrower" for John Cleese on his Video Arts training videos.
Cleese needed a funny number for the punchline to a sketch involving a bank teller (himself) and a customer (Tim Brooke-Taylor). Adams believed that the number that Cleese came up with was 42 and he decided to use it.
Adams also had written a sketch for The Burkiss Way called "42 Logical Positivism Avenue", broadcast on BBC Radio 4 on - 14 months before the Hitchhiker's Guide first broadcast "42" in fit the fourth, .
In January 2000, in response to a panelist's "Where does the number 42 come from?" on the radio show "Book Club" Adams explained that he was "on his way to work one morning, whilst still writing the scene, and was thinking about what the actual answer should be. He eventually decided that it should be something that made no sense whatsoever- a number, and a mundane one at that. And that is how he arrived at the number 42, completely at random."
Stephen Fry, a friend of Adams, claims that Adams told him "exactly why 42", and that the reason is "fascinating, extraordinary and, when you think hard about it, completely obvious." However, Fry says that he has vowed not to tell anyone the secret, and that it must go with him to the grave. John Lloyd, Adams' collaborator on The Meaning of Liff and two Hitchhiker's fits, said that Douglas has called 42 "the funniest of the two-digit numbers."
There is the persistent tale that forty-two is actually Adams' tribute to the indefatigable paperback book, and is really the average number of lines on an average page of an average paperback book.
42 Puzzle
The 42 Puzzle is a game devised by Douglas Adams in 1994 for the United States series of The Hitchhiker's Guide to the Galaxy books. The puzzle is an illustration consisting of 42 multi-coloured balls, in 7 columns and 6 rows. Douglas Adams has said,{|align="center" class="cquote2" style="border-style: none; border-collapse: collapse; background-color: transparent;" |valign="top" width="20" style="padding: 10px; color: rgb(178, 183, 242); font-size: 40px; font-family: serif; font-weight: bold; text-align: left;"|“ |valign="top" style="padding: 4px 10px;"|Everybody was looking for hidden meanings and puzzles and significances in what I had written (like 'is it significant that 6 * 9 is 42 in base 13?'. As if.) So I thought that just for a change I would actually construct a puzzle and see how many people solved it. Of course, nobody paid it any attention. I think that's terribly significant. |valign="bottom" width="20" style="padding: 10px; color: rgb(178, 183, 242); font-size: 40px; font-family: serif; font-weight: bold; text-align: right;"|” |}In the puzzle the question is unknown, but the answer is already known to be 42.
The puzzle first appeared in The Illustrated Hitchhiker's Guide to the Galaxy. It was later incorporated into the covers of all five reprinted "Hitchhiker's" novels in the United States.
Six of the solutions are:
| How many spheres are in the diagram? (six rows of seven is 42) | What position in the grid does the computer that calculates the Question to the Ultimate Answer (the Earth) occupy? (42) | The barcode is the number 42 as an Interleaved 2 of 5 barcode |
| Considering red-hued spheres (red, purple, orange, black) as a '1' and those without as a '0', what number does each line represent in decimal form? (In binary, each line reads '0101010', or '42' in decimal form.) | What number do the blue-tinted spheres (blue, green, purple, black) spell out? (Similar to a color blindness test.) (42) | What number is represented by Roman numerals spelled out by the yellow-tinted spheres (yellow, orange, green, black) in the first three rows? (XLII = 42) |
The number 42 and the phrase, "Life, the universe, and everything" have attained cult status on the internet. "Life, the Universe, and Everything" is a common name for the off-topic section of an internet forum and the phrase is invoked in similar ways to mean "anything at all". Many chatbots, when asked about the meaning of life, will answer "42". Several online calculators are also programmed with the Question. If you type the answer to life, the universe and everything into Google (without quotes or capitalising the small words), the Google Calculator will give you 42. If you type 'answer to life, the universe, and everything' into Wolfram's Computational Knowledge Engine it provides the result '42'. Microsoft's Bing search engine will also give you 42.Alphasmart 3000's calculator, when given any equation that results in 42, will display, "The answer to life, the universe, and everything". In the online community "Second Life," there is a section on a sim called "42nd Life." It is devoted to this concept in the book series, and several attempts at recreating Milliways, the Restaurant at the End of the Universe, were made.
In the Stargate Atlantis Season 4 episode "Quarantine", 42 are the last two digits in Rodney McKay's password. After John Sheppard explains to Teyla the meaning of the previous twelve digits, she asks him what 42 is. Then, John says, "It's the ultimate answer to the great question of life, the universe, and everything," at which point Teyla looks confused.
In the TV show Lost, 42 is the last of the mysterious numbers, 4, 8, 15, 16, 23, and 42. In an interview with Lostpedia, producer David Fury confirmed this was a reference to Hitchhiker's.
The TV show The Kumars at No. 42 is so named because show creator Sanjeev Bhaskar is a Hitchhiker's fan.
The band Coldplay's album Viva la Vida includes a song called "42". When asked by Q magazine if the song's title was Hitchhiker's-related, Chris Martin said, "It is and it isn't."
The band Level 42 chose its name in reference to the book.
In the PC game Spore, once reaching the center of the galaxy, Steve the UFO will present you with the Staff of Light that can make any planet livable- but can only be used 42 times.