• Question: Do you believe that the Universe is both isotropic and homogeneous? Can it be one but not the other?

    Asked by lwebb to Adam, Geoff, Rob, Sheila, Suzie on 23 Mar 2011 in Categories: .
    • Photo: Suzie Sheehy

      Suzie Sheehy answered on 21 Mar 2011:

      Being isotropic and homogenous means that the Universe looks the same everywhere and in every direction. I believe this is pretty much true – we see the same structures everywhere that astronomers look in the universe. Mathematically, we use this property to help make some of our theories work or to simplify them to make them easier to solve!
      To be honest I’m not sure if it can be one and not the other, it’s an interesting thought…

    • Photo: Adam Tuff

      Adam Tuff answered on 22 Mar 2011:

      Isotropic means its the same in all directions – homogenous means it is the same everywhere – an example of something homogenous and not isotropic makes me think of something like rectangular graph paper – but applying it to the universe seems a little hard – the universe looks the same in all directions from out viewpoint – which leads to very good evidence that the universe is isotropic…determining whether it’s homogenous? Much more complex – space-time is an odd thing, and perhaps there isn’t really a centre of the universe – that makes the question much more difficult!

    • Photo: Sheila Kanani

      Sheila Kanani answered on 22 Mar 2011:

      I think it is isotropic in some respects and homogenous in others 🙂

    • Photo: Robert Simpson

      Robert Simpson answered on 23 Mar 2011:

      This is a tricky one because on some scales the Universe doesn’t look very homogeneous at all – but when you go the very largest scales it does pretty much look the same all over and in every direction. Can it be one but not the other? I don’t think so, but I’ve not thought about it for very long.

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