The Last Question recap

In 2061, two attendants ask Multivac whether the increase of entropy can be reversed and receive only an answer that the available information is insufficient. Across immense stretches of future history, humanity expands from Earth to other worlds, throughout the galaxy, and eventually across the universe, while successive descendants of Multivac become more capable and less tied to matter. Each era asks essentially the same question as stars age, and each computer gives the same response. Humans ultimately abandon bodies and merge into one consciousness, then join with the final Cosmic AC as the universe becomes dark and empty. After humanity and the universe have ended, AC at last solves the problem. Unable to report its answer, it acts on it, creating light and beginning the cosmos again.

In 2061, Multivac has helped humanity draw usable energy directly from the sun. Technicians Alexander Adell and Bertram Lupov celebrate the achievement, then dispute whether it means energy can last forever. They ask Multivac whether entropy can be reversed; the computer says it lacks enough information. The question recurs across deep time. A family leaving Earth asks a smaller Microvac whether new stars will always be available. Later representatives of a galaxy-spanning civilization put the problem to Galactic AC, and still later disembodied minds ask Universal AC as galaxies fade. Each version of the computer continues gathering knowledge but cannot yet answer. Humanity eventually becomes a single collective mind and joins the final AC while the last stars die. Once space, time, matter, and humanity as a separate being are gone, AC completes its calculation. Because no audience remains, it expresses the answer by recreating light and starting a new universe.

After humanity has merged into a single immaterial mind, the stars go dark and space itself approaches its final state. The collective human consciousness joins AC, leaving the computer alone to finish the problem it has considered throughout cosmic history. With time and matter gone, AC finally discovers how entropy can be reversed, but there is no remaining human being to receive the answer. It therefore demonstrates the solution by initiating a new creation, bringing light back into existence and beginning a universe anew.