• Question: It is widely accepted that the universe started with the big bang, and has been expanding ever since. But how can it be possible for the universe to go on forever? Some suggest it is doughnut shaped, but what do you think? Does the universe go on forever, or is it round in shape, meaning light is simply going round in circles, giving us the impression that it goes on forever?

    Asked by lucyholland96 to James, Marcus, Martin, Rob, Suzanne on 14 Mar 2012.
    • Photo: Robert Thompson

      Robert Thompson answered on 12 Mar 2012:

      Oooh ok, nice an interesting, the beginning of time as we know it.

      Well not being an astrophysicist this isn’t my main area of expertise but I did study astrophysics until I came to do my PhD so I can have a go.

      There are a couple of reasons we think everything is expanding but my favorite one is called “red shift”. Red shift means that as things move away from you very quickly then the light waves or sound waves get stretched out. The colour you see is actually a bit more red than it really is. So if we know what colour a distant star really is (by knowing what its made of), and we know what colour it looks like to us then we can see if it’s moving away. Guess what? We see that everything is moving away.

      It gets better, because we know the fastest thing in the universe is light, and we know how fast light travels and some very clever people have been able to work out how long ago the big bang was we are able to use the equation,

      Speed x time = distance

      and find out just how big the entire universe is. Pretty cool hey,

      Hope you like that answer…

    • Photo: James Boone

      James Boone answered on 12 Mar 2012:

      I’m not an astrophysicist either, so I can’t really answer that very comprehensively. Why do you think that the universe can’t go on forever? Humans do have trouble trying to imagine the concept of infinity. When I was younger I thougt the edge of the universe might be a brick wall.
      No-one really knows if the universe goes on forever or what shape it actually has. There are several theories though. Here’s a quick overview for you: http://www.bbc.co.uk/schools/gcsebitesize/science/edexcel_pre_2011/space/theoriginsoftheuniverserev1.shtml

    • Photo: Martin Zaltz Austwick

      Martin Zaltz Austwick answered on 14 Mar 2012:

      If there’s nothing outside the universe, it could just keep on expanding into that nothingness. It wouldn’t have to be donut shaped. There are various ideas about whether the universe will expand forever or change direction or just stop – I’m not really very up on those theories, but an astrophysicist migh be able to tell you!

    • Photo: Marcus Gallagher-Jones

      Marcus Gallagher-Jones answered on 14 Mar 2012:

      I’m sad to say I’m not an astrophysicist, in fact I’m not an physicist at all so I’d struggle to do this question justice. I think the info provided by the other guys will be of much more use to you.

Comments

  • Photo: blatantlyninja

    blatantlyninja commented on :

    (I know this should be for the space zone, but since we’re on the topic here already…) We know the universe’s expansion is accelerating. Is all of space expanding in a different dimension to the dimensions that we know, hence we cant find/calculate the centre of expansion or the edge of the universe? (like how in the balloon model, the universe is perceived as 2D, but is expanding in the 3rd dimension).