• Question: do you think time travel will ever be possible ?

    Asked by Sophie to Gavin, Karen, Mark, Michel, Roisin on 9 Nov 2016. This question was also asked by leila, 925xygg26.
    • Photo: Michel Destrade

      Michel Destrade answered on 9 Nov 2016:

      No, from a logical point of view I don’t think so, otherwise time travelling tourists would have visited us.

    • Photo: Roisin Jones

      Roisin Jones answered on 10 Nov 2016:

      I don’t think it will unfortunately, because it would be an amazing thing to be able to view history in person! However, I think that successful time travel is hypothesised to require the traveler to move at faster than the speed of light, which is impossible. Also, in support of Michel’s answer, Stephen Hawking held a party for time-travellers, which he announced the day after it was held…and nobody showed up! So seems unlikely we’ll ever be seeing visitors from the future.

    • Photo: Mark Kennedy

      Mark Kennedy answered on 10 Nov 2016:

      Roisin raised a good point about time travel requiring you to move faster than light to time travel, which isn’t really possible (from what we know. Maybe we could travel through wormholes, or outside the Universe, and this could allow for time travel).

      Allow me to propose to you another scenario. Rather than just a single person moving through time, would it be possible to move the entire Universe back in time? After all, time is just another dimension we move through. And you can move forward and backward and sideways in the spatial dimension – why can’t we do this with time? Why do we only ever move forwards in time?

      Because of entropy. The Universe wants to move towards a high state of entropy. Everything likes to move towards high entropy! If I gave you a box which had nothing in it (a vaccum) and then you released a load of gas into it, would the gas all just sit in one corner (which would be a low state of entropy)? Of course not, it would spread out and occupy the whole box equally (which is a high state of entropy). The Universe is the same – it’s constantly moving towards a higher state of entropy. And if you tried to move the entire Universe backwards in time, you’d be trying to force it into a lower state of entropy.

      Which it really, really wouldn’t like. In fact, you might break it by trying to do that. So please don’t. I like our Universe to be not broken.

      Here are some really good videos on entropy and the Universe and your part in all of this: https://www.youtube.com/watch?v=yKbJ9leUNDE

    • Photo: Karen

      Karen answered on 10 Nov 2016:

      No I don’t think so…in the words of lady Macbeth “what’s done is done…and cannot be undone”. Wise woman was Lady Mc

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