The Nine Billion Names of God

In a Tibetan lamasery, the monks seek to list all of the names of God. They believe the Universe was created for this purpose, and that once this naming is completed, God will bring the Universe to an end. Three centuries ago, the monks created an alphabet in which they calculated they could encode all the possible names of God, numbering about 9,000,000,000 ("nine billion") and each having no more than nine characters. Writing the names out by hand, as they had been doing, even after eliminating various nonsense combinations, would take another 15,000 years; the monks wish to use modern technology to finish this task more quickly.

They rent a computer capable of printing all the possible permutations, and hire two Westerners to install and program the machine. The computer operators are skeptical but play along. After three months, as the job nears completion, they fear that the monks will blame the computer (and, by extension, its operators) when nothing happens. The Westerners leave slightly earlier than scheduled departure without warning the monks, so that it will complete its final print run shortly after they leave. On their way to the airfield they pause on the mountain path. Under a clear night sky they estimate that it must be just about the time that the monks are pasting the final printed names into their holy books. Then they notice that "overhead, without any fuss, the stars were going out."

Assuming the monks' alphabet has ${\displaystyle n}$ letters, then according to the Lama's description, the set of all possible names of God is the set of strings following two conditions:

• It has length in ${\displaystyle \{1,2,...k\}}$ with ${\displaystyle k=9}$
• It has no more than three consecutive equal letters.

The number of such strings is

$${\displaystyle \sum _{l=0}^{k-1}{\begin{bmatrix}n&0&0\end{bmatrix}}{\begin{bmatrix}n-1&1&0\\n-1&0&1\\n-1&0&0\end{bmatrix}}^{l}{\begin{bmatrix}1\\1\\1\end{bmatrix}}}$$

Setting ${\displaystyle n=12}$ gives 5.6 billion names of God, and ${\displaystyle n=13}$ gives 11.5 billion names of God for the short scale definition of billion (10⁹), or alternatively, ${\displaystyle n=27}$ gives 7.9 billion names of God, and ${\displaystyle n=28}$ gives 11 billion names of God for the long scale definition of billion (10¹²). In 1953 a British writer would usually have used the long scale while an American would use the short scale; however it is possible Clarke, writing for an American audience, meant the short scale. Writing 10¹² names over 15000 years requires that just over two names a second be written on average, while printing 10⁹ names over 100 days means printing 127 names a second.

In 2004, "The Nine Billion Names of God" won the retrospective Hugo Award for Best Short Story for the year 1954.[1] Kirkus Reviews called it "quietly remarkable",[2] and The Guardian considered it to be a "wonderful apocalyptic rib-tickler".[3] Stating that the story "introduced many Western readers to an intriguing speculation in Oriental religions", Carl Sagan in 1978 listed "The Nine Billion Names of God" as among the "rare few science‐fiction [stories that] combine a standard science‐fiction theme with a deep human sensitivity".[4] In 1986 it was included in the anthology Isaac Asimov Presents The Great SF Stories 15 as one of the best science fiction short stories of 1953.

Gary K. Wolfe noted that the story is "patently at odds with Clarke's scientific rationalism".[5] Paul J. Nahin has pointed out that, due to the delay imposed by the speed of light, an omniscient God would have had to destroy all the stars in the universe years earlier so that their "synchronized vanishing" would be visible at exactly the time that the monks completed their task.[6]

In 2003, Clarke reported having been told that the Dalai Lama had found the story "very amusing".[7]

In 2011 the story was loosely adapted into a Portuguese short film, Scr1ptum, by Swiss director Matthias Fritsche.[8] In 2018, the story was adapted into a 2018 short film by Dominique Filhol.[9]

• Names of God
• Brute-force attack
• Tower of Hanoi, a puzzle whose legendaria incorporate a similar end to the Universe
• "The Library of Babel", a 1941 short story by Jorge Luis Borges which also deals with collecting all the possible permutations of a character string
• "The Fife of Bodidharma", a 1959 short story by Cordwainer Smith, reprinted in The Rediscovery of Man
• Jorge Palma, a Portuguese singer whose 1972 song was named after and inspired by the story
• "The Nine Billion Names of God", a 1984 short story by Carter Scholz about an exact replica of Clarke's story[note 1]
• Darren Aronofsky's Pi (1998), in which a computer is used to divine the 216-character name of God
• "Seventy-Two Letters", a 2000 novella by Ted Chiang
• "Godfellas", a 2002 Futurama episode partially inspired by the story
• "Last Contact", a 2007 short story by Stephen Baxter about humans experiencing the universe ending in a Big Rip

• The Nine Billion Names of God title listing at the Internet Speculative Fiction Database
• James Randi praising The Nine Billion Names of God as his favourite Clarke story Audio interview the day after Clarke's death