• Question: Could there ever be a parallel universe?

    Asked by to Aimee, Chris, Dave, Greig, Laurence on 17 Jun 2014. This question was also asked by .
    • Photo: Greig Cowan

      Greig Cowan answered on 17 Jun 2014:

      Yes, definitely. Some scientists believe that there are an infinite number of Universes, all being slightly different 🙂

    • Photo: Dave Jones

      Dave Jones answered on 17 Jun 2014:

      It’s definitely possible! There is even a theory which states that there are an almost infinite number of Universes each of which exists in a higher dimension that the 4 that we experience (the 3 spacial dimensions and time). It is even possible that the interaction between these Universes in these higher dimensions was what caused the Big Bang! Just to make the theory sound even crazier, it is called “Brane World Theory” because the name they give to each Universe in this set-up is “a brane”. Crazy, yeah?

    • Photo: Laurence Perreault Levasseur

      Laurence Perreault Levasseur answered on 17 Jun 2014:

      yes, there could be. However they are not really ‘parallel’ in the sense of in the same physical place as us, and in a different level of reality. Rather, they are just so far away from us that they are beyond our observable Universe.

      Observable Universe is a fancy word to say the furthest stuff we can see in the Universe because light has had time to travel from that stuff to us since the Big Bang. Everything beyond that is so far that light hasn’t had time to reach us.

      So. How do parallel universes come about then? It’s because just after the Big Bang there was a period of inflation, when space was expanding exponentially fast. During that time, tiny pieces of space were stretched well beyond the size of the observable Universe today. Now if we imagine that inflation ended in some parts of the Universe, but not everywhere at the same time. Then, say, here, in a little bubble, inflation has ended, and our normal Universe as we see it starts evolving. But everywhere outside that bubble, the Universe is still expanding like crazy and inflation is still going on!

      Then in a little bubble somewhere else inflation ends at a different time, and another universe start evolving, with similar properties as our own, but maybe slightly different, because, after all, it’s not the same place, nor the same Universe!!

      Even with those two bubble universes, there is still a lot of space in inflation, and the amount of space in inflation is MUCH bigger (and constantly becomes bigger) than the space where inflation has stopped. So I can basically create an infinite amount of ‘little’ (I mean, they are still bigger than our observable universe today!!!) bubble Universes, and still have even more space in inflation, outside of those bubbles.

      They will all be different, be at different places, and have different stuff in it. But I think these are the ‘parallel’ Universe you were referring to (am I correct?). This theory where some part of space is always in inflation is called ‘eternal inflation’ and the ensemble of all the bubble universes is called the ‘multiverse’.

      This theory has some problems to it, though. Since to test it we’d have to go outside of our observable universe, which it’s impossible, it doesn’t yet make any testable prediction. This means that many scientists think it’s not a scientific theory, because it cannot be falsified by experiment.

    • Photo: Aimee Hopper

      Aimee Hopper answered on 17 Jun 2014:

      Could there, probably. Dont see why not. Unfortunately it’s not something that we’ll ever be able to prove/disprove, unless we discover faster than light travel!

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