• Question: Could there ever be a time machine?

    Asked by nessy123 to Adam, Joanna, Marcus on 22 Nov 2012.
    • Photo: Joanna Giles

      Joanna Giles answered on 22 Nov 2012:

      Personally, I’m a little cynical on the idea of time travel and think that there are too many obstacles in the way and so time travel would probably not be possible.

      However! Experts in the field (so that’s the physics guys) do admit that there are no mathematical explanations to say that time travel isn’t possible. Einstein came up with the first equations explaining that time and space could be related, and since those equations (back in the 1900s) no scientist has been able to go from there to prove that going BACK in time is not possible. But it wouldn’t necessarily be by a “Time machine” more by black holes and worm holes in outer space.

      If you could go back in time (or forward for that matter) would you want to? Maybe curiosity would get the better of me and I would, but I would try really hard not to in case I did something that would change the course of the past – like the butterfly effect.

      (The butterfly effect is a “Chaos theory” that says that a tiny input can have a massive effect on something else. So if a tiny butterfly flaps it’s wings in one place, this might lead to a hurricane occurring in another place. So basically if you went back in time you could drastically change the course of the future – have you seen the “Back to the Future” movies?)

    • Photo: Adam Paige

      Adam Paige answered on 22 Nov 2012:

      Yeah time travel is a real difficulty for physicists. There is the famous Grandfather paradox – the idea that if you went back in time you could (accidentally) kill one of your ancestors, which means you could never have been born, so how could you have gone back in time and killed someone? But if you didn’t go back and kill that person then you could be born and therefore you could have gone back in time and killed them…!!! It seems so illogical that it feels as though it can’t be possible. However, the mathematical models of time and space that we know work so well do not prevent the idea of time travel. The maths says it should be possible (though not necessarily easy).

      One possible way around the paradox is the idea of alternate universes. If we travel back in time from our universe (which I shall call universe 1) and accidentally kill our grandfather, perhaps this would create an alternate universe (universe 2 – one identical to ours up to that point but then different afterwards because of the lack of our grandfather in that universe). In universe 2 “our grandfather” died so the universe 2 copy of us could not be born. But we could still be there, because we actually came from universe 1 where our grandfather had not died and we could therefore be born. I realise how confusing and crazy that sounds (sorry) but it is one idea to avoid the paradox of time travel. And it makes a great plot in many superhero comics and sci-fi movies!

      If you don’t like the alternate world idea, then take comfort from the fact that one of the greatest physicists of the current day, Stephen Hawking, believes that it is impossible to travel in time. He thinks that if you were to try there would be some kind of energy production that would stop it happening (I do not understand the physics of this though).

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