• Question: Is it actually possible for history to ever repeat itself?

    Asked by beckyh to Arttu, James_M on 23 Jun 2011.
    • Photo: Arttu Rajantie

      Arttu Rajantie answered on 23 Jun 2011:

      Probably not in reality, although we are not quite sure. There are cosmological theories in which the universe has existed forever, and would for example be going through repeated cycles of big bangs and big crunches. There cycles could be exactly identical, and then we would be repeating the same history over and over again. However, even if they are not identical, history would eventually repeat itself after a very, very large of these cycles. This is known as Poincare recurrence.

      Of course, we don’t have a memory of the previous cycles, if these theories are true then in principle we could find some signs of the previous cycle especially in the early universe.

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