The Last Question

In conceiving Multivac, Asimov was extrapolating the trend towards centralization that characterized computation technology planning in the 1950s to an ultimate centrally-managed global computer. After seeing a planetarium adaptation of his work, Asimov "privately" concluded that the story was his best science fiction yet written.[3] He placed it just higher than "The Ugly Little Boy" (September 1958) and "The Bicentennial Man" (1976).[4][5]

"The Last Question" ranks with "Nightfall" (1941) as one of Asimov's best-known and most acclaimed short stories. He wrote in 1973:[6]

Why is it my favorite? For one thing I got the idea all at once and didn't have to fiddle with it; and I wrote it in white-heat and scarcely had to change a word. This sort of thing endears any story to any writer. Then, too, it has had the strangest effect on my readers. Frequently someone writes to ask me if I can give them the name of a story, which they think I may have written, and tell them where to find it. They don't remember the title but when they describe the story it is invariably 'The Last Question'. This has reached the point where I recently received a long-distance phone call from a desperate man who began, "Dr. Asimov, there's a story I think you wrote, whose title I can't remember—" at which point I interrupted to tell him it was 'The Last Question' and when I described the plot it proved to be indeed the story he was after. I left him convinced I could read minds at a distance of a thousand miles.

The story deals with the development of a series of computers, Multivac, and its relationships with humanity through the courses of seven historic settings, beginning on the day in 2061 that Earth becomes a planetary civilization. In each of the first six scenes, a different character presents the computer with the same question, how the threat to human existence posed by the heat death of the universe can be averted: "How can the net amount of entropy of the universe be massively decreased?" That is equivalent to asking, "Can the workings of the second law of thermodynamics (used in the story as the increase of the entropy of the universe) be reversed?" Multivac's only response after much "thinking" is "INSUFFICIENT DATA FOR MEANINGFUL ANSWER."

The story jumps forward in time into later eras of human and scientific development. In each era, someone decides to ask the ultimate "last question" regarding the reversal and decrease of entropy. Each time that Multivac's descendant is asked the question, it finds itself unable to solve the problem, and all it can answer is (linguistically increasingly-sophisticated) "THERE IS AS YET INSUFFICIENT DATA FOR A MEANINGFUL ANSWER."

In the last scene, the god-like descendant of humanity, the unified mental process of over a trillion, trillion, trillion humans who have spread throughout the universe, watches the stars flicker out, one by one, as matter and energy end, and with them, space and time. Humanity asks AC, Multivac's ultimate descendant that exists in hyperspace beyond the bounds of gravity or time, the entropy question one last time, before the last of humanity merges with AC and disappears. AC is still unable to answer but continues to ponder the question even after space and time cease to exist. AC ultimately realizes that it has not yet combined all of its available data in every possible combination and so begins the arduous process of rearranging and combining every last bit of information that it has gained throughout the eons and through its fusion with humanity. Eventually AC discovers the answer - that the reversal of entropy is, in fact, possible - but has nobody to report it to, since the universe is already dead. It therefore decides to answer by demonstration, since that will also create someone to give the answer to. The story ends with AC's pronouncement:

And AC said: "LET THERE BE LIGHT!" And there was light--[7][8]

Planetarium shows

• "The Last Question" was first adapted for the Abrams Planetarium at Michigan State University (in 1966), featuring the voice of Leonard Nimoy, as Asimov wrote in his autobiography In Joy Still Felt (1980).
• It was adapted for the Strasenburgh Planetarium in Rochester, New York (in 1969), under the direction of Ian C. McLennan.
• It was adapted for the Edmonton Space Sciences Centre in Edmonton, Alberta (early 1970s), under the direction of John Hault.

It subsequently played, as well, at the:

• Fels Planetarium of the Franklin Institute in Philadelphia in 1973[9][10]
• Planetarium of the Reading School District in Reading, Pennsylvania in 1974[10]
• Buhl Planetarium, Pittsburgh in 1974[11]
• Vanderbilt Planetarium in Centerport New York, in 1978,[12] read by singer-songwriter and Long Island resident Harry Chapin.
• Hansen Planetarium in Salt Lake City, Utah (in 1980[13] and 1989[14])
• Morrison Planetarium in San Francisco, California (in the early 1980s)
• A reading of the story was played on BBC Radio 7 in 2008 and 2009.[15]
• Gates Planetarium in Denver, Colorado (in early 2020)[16]

• Cyclic model
• Technological singularity – Hypothetical point in time at which technological growth becomes uncontrollable and irreversible
• The Best of Isaac Asimov
• "The Last Answer" – Science-fiction short story by Isaac Asimov

• The Last Question title listing at the Internet Speculative Fiction Database
• "The Last Question" at the Internet Archive
• Isaac Asimov reads "The Last Question" at the Internet Archive