Short story read in the 1960s. Story begins with the very large early tube and relay computers which occupied whole building and sometime city blocks. A couple of drunk computer engineers ask the computer to theorize on entropy or the death of all life, heat energy, and what could be done to halt entropy. The story describes computer evolution into a future where the computer existed in another dimension. Users contacted the computer via a ring on their fingers. And, through history many people asked the same question. "Why does everything have to end?" The final human dies. The final star freezes. Yet, the computer continues to think about the one question. Finally the Computer comes of with the answer and says. "Let there be Light and there was Light."
The last question was asked for the first time, half in jest, on May 21, 2061, at a time when humanity first stepped into the light. The question came about as a result of a five dollar bet over highballs, and it happened this way ...
The consciousness of AC encompassed all of what had been a Universe and brooded over what was now Chaos. Step by step, it must be done.
And AC said, "LET THERE BE LIGHT!"
And there was light--
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.