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the world of sci-fi science-truth or fiction

edited October 2009 in - Reading


  • Regarding the Grandfather Paradox in time travel, I think there are many other theories to challenge this. It’s a bit like Marty McFly in Back to the Future where his mum was falling in love with him and not his dad so he would never exist
    One argument to challenge this is obviously the fork in the river, or parallel universe argument and another is no constant causality.

    My favourite theory though is the fork in the river. It means if you make a mistake (kill your own grandfather) then a fork will appear in the river of time and you will travel down this new road where time is fixed and your grandfather was never killed in the first place.
    Which is a bit spooky in the real world as the scientist at the Large Hadron Collider are now saying the machine is breaking due to it knowing it is going to be used for a catastrophe in the future and is sabotaging itself in the past.

    The best example ever though is the episode of Futurama called ‘Roswell That Ends Well’. If you haven’t watched it download it give it a go.
    Sorry to go on but I’m obsessed with time travel and have been all my lives.
  • with our knowledge of DNA Time Travellers would know the Dna type/history and would not go where they might jeopardise their past/future.

    If it becomes possible in the future to travel in Time to the past then it must be happening now and has been for some time....

    ...which might mean that repeated sightings over the years of ufo in the same places... may be actually the same one... sighted years apart by different people....
  • Since there are more dimensions than we know what to do with, time travel in the future is certainly very possible, assuming they've worked out how to avoid all the paradoxes. Certainly the Grandfather Paradox would go on ad infinitum, so it would be interesting how this is solved.
  • I'll post the answer to that.....
    last friday....:-)
  • The caveat to the grandfather paradox is that anything that is in the present (future) must have found a way to be there so anything that is destroyed in the past must have found a way to heal itself.
    If I went back in time and shot my dad then according to the GP I would not be born. However if I was never born how could I have travelled back to the past to shoot my own father?
  • Ah I see...
  • Of course we could avoid killing people when we travel back in time which would solve the problem. As most of us go our whole lives without killing anyone, would it really be such a strain to hold back all murderous feelings whilst we pop back to 1962 for a couple of hours?
  • lol PM very good point. I never read theories or paradoxes that talk about sending nice cards or saying I love you. However saying that it's not really about the killing, it’s just a way to emphasise a dramatic change in the time line.
    That card that was sent could take a postman to a house where there was a bomb; the house blows up and kills the postman. That postman was about to go on his honeymoon the week after where he would conceive a baby with his wife, that baby would have been the only scientist to discover the cure for AIDS or cancer.

    It’s really to do with causality. Think of Ray Bradbury’s prehistoric butterfly for example. Only a small thing but it could change or even destroy the world.
  • Going back in time and killing your grandfather or indeed your father is where you vanish by wiping yourself from existence, you haven't been born. By that effect, your grandfather or father have not been killed, and you end up being born and then the process will start over and cause a paradox, infinite loop of you killing your grandfather/father.
  • Or time travel can only be done in parallel universes. So you only killed a parallel grandfather so your parallel dad will not be born and neither will your parallel self. When you travel back to your present you are still there because your real grandfather and dad were never visited.
  • Indeed, and let's not forget time doesn't travel in a straight line, so you can have any number of loops and parallel loops going off all over the place. How mind boggling!
  • Very boggling but interesting. This is before you even consider black holes, space and time bending or wormholes.
  • Or ripple effects or chaos theory interfering...
  • Isn't Terminator Two (the best of them) all about backwards and forwards in time? And there's a cracking story by John Wyndham called 'Consider Her Ways' which works on this theme too. Why is John Wyndham not more popular - I think he needs a comeback!
    The whole subject is completely fascinating.
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