• Question: Can I have a basic overview of StringTheory

    Asked by yoloswagmaster123 to Joel, Kristian, Tim, Venus, Zachary on 20 Nov 2013.
    • Photo: Tim Hollowood

      Tim Hollowood answered on 20 Nov 2013:

      Thanks the the question. OK here’s a basic overview of string theory. In the usual theory of PARTICLE physics the basic building blocks are the particles, so the electron, the quarks, etc. So we need quite a few particle to make the Standard Model of particle physics. But there a problem gravity does not seem to fit into the model. String theory theory is way of unifying gravity with all the other forces. It does this by replacing the particles by tiny strings…think of little elastic bands that are so tiny that to our experiments they look like point particles. But the nice thing is that we can account for all the particle by one kind of string vibrating in different ways, like notes on a guitar string. But the really cool thing is that string theory has gravity in it almost for free. So that’s why it’s so important and interesting to study.

    • Photo: Kristian Harder

      Kristian Harder answered on 20 Nov 2013:

      Tim is a master of string theory, so his answer wins, but there’s one more thing that I’ve heard about why we love string theory so much.
      Our description of the universe based on particles assumes that these particles are pointlike. Really pointlike, meaning they have no size. They are assumed to be infinitely small. But that is a bit of a problem, because it leads to infinities all over the place. Imagine for example you get two electrically charged particles very close together. The closer you get them together, the stronger the force between them becomes. If the particles are infinitely small, you can get them infinitely close to each other without having them bump into each other. But then the force gets infinitely strong, and it would take infinite energy to get the particles away from each other again. But this is not how nature works. These infinities do not actually exist. So what you do in the mathematical description of the universe is basically just cut off everything beyond certain values. You pretty much artificially cut out the infinities, and voila, the whole thing gives your finite and proper results. We call that renormalization. It seems a bit haphazard, and if it didn’t work so well in practice, we’d probably be very embarrassed about it. 🙂
      Now, the miraculous thing that happens if your particles are not points, but one-dimensional strings, is that all these problems disappear. You don’t run into these kind of infinities anymore, and thus you don’t need to invent these weird procedures to get rid of them in actual calculations.
      Sound a lot more natural?
      EXACTLY. 🙂

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