I saw Eternity the other night
Like a great Ring of pure and endless light
    All calm as it was bright;
And round beneath it, Time, in hours, days, years,
    Driven by the spheres.
Like a vast shadow moved, in which the world
    And all her train were hurled.
                              — From "The World" by Henry Vaughan

Twenty-one years after its publication in Analog, here is Marc Stiegler's story The Gentle Seduction: nanotechnology and the hours, the days, the years, and the billennia.