Origins of the idea and Nietzsche's horror

This notion, it must be admitted, was not original with Nietzsche and it would have been better for his philosophy and for his repute as an intelligent thinker had he never sought to elucidate it. In his early essay on history he first mentioned it and there he credited it to its probable inventors--the Pythagoreans.[1] It was their belief that, whenever the heavenly bodies all returned to certain fixed relative positions, the whole history of the universe began anew. The idea seemed to fascinate Nietzsche, in whom, despite his worship of the actual, there was an ever-evident strain of mysticism, and he referred to it often in his later books. The pure horror of it--of the notion that all the world's suffering would have to be repeated again and again, that men would have to die over and over again for all infinity, that there was no stopping place or final goal--the horror of all this appealed powerfully to his imagination. Frau Andreas-Salomé tells us that he "spoke of it only in a low voice and with every sign of the profoundest emotion" and there is reason to believe that, at one time, he thought there might be some confirmation of it in the atomic theory, and that his desire to go to Vienna to study the natural sciences was prompted by a wish to investigate this notion. Finally he became convinced that there was no ground for such a belief in any of the known facts of science, and after that, we are told, his shuddering horror left him.