• Question: How can the universe be finitely big with no edges?

    Asked by lizzie3006 to Ben, Jony, Katharine, Mark, Peter on 19 Nov 2011.
    • Photo: Jony Hudson

      Jony Hudson answered on 18 Nov 2011:

      A sphere is finitely big with no edges, as is a torus (donut).

      That said, I totally don’t understand any of this finite universe cosmology stuff, so I’ll be interested to see what the other scientists have to say!

    • Photo: Mark Basham

      Mark Basham answered on 18 Nov 2011:

      I’m not an expert either, but I think Jony has it right, The current thinking is something like a 4D doughnut, So if you go in any direction for long enough, you will eventually arrive back where you started. However this is expanding, so as time goes on it will take longer and longer to get back to where you started.

      Hope this helps

    • Photo: Peter Williams

      Peter Williams answered on 19 Nov 2011:

      Just like Jony and Mark say.
      The odd thing is that the universe seems to be very finely balanced on the cusp between being closed, like a sphere, or being open, like a saddle shape. Why this is is not understood.

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