• Question: if people will invent time machines to bring people from the dead back will that disturb other people time traveling eg. if I was 2009 and somebody died and we were in 2010 and i time travelled back would other people that was brought back from the dead disapear because of the disturbance of time?

    Asked by claremcglone to Amy, Drew on 24 Jun 2011.
    • Photo: Drew Rae

      Drew Rae answered on 24 Jun 2011:

      Hi Clare. I think time travel confuses us all, because there are different ways it might work, if it worked at all. Here’s a rough overview of the major theories and the consequences for your question:

      1) The branching universe theory – When you go back in time and change things, there are now two universes, one where you changed things and one where you didn’t.

      In this universe, after you saved the dead person, you would be in a totally new universe. That person would never have died, and lots of other things might have changed as a consequence.

      2) The time heals itself theory – you can try to change history, but to avoid paradoxes it minimises the disturbance. You save someone’s life, but they get hit by a bus anyway two minutes later.

      3) The paradox theory – you save the person’s life, and as a consequence the time machine never gets invented or built, so you don’t go back in time to save the person’s life, so the person dies and the time machine does get built, and the entire universe explodes or gets trapped in a time loop.

    • Photo: Amy MacQueen

      Amy MacQueen answered on 24 Jun 2011:

      Hmmmmm…..this is incredibly confusing. Are you saying that people are bringing other people back from the past and that you have been back into the past but are now returning to the present (i.e. moving forward in time?). In which case you think that with you moving forward in time the universe will get confused and the people who had died in the place that you have been that the other people have since gone back in time to bring back to life are dead to you so should be dead when you arrive in the present?

      If this is the case you are getting into multiple universes where different things are happening. Time travel is generally thought to be impossible – and if it did work I would argue that scientific theory then sort of goes out the window (at least without multiple parallel universes) because causes and effects aren’t going to match up. My best advice is to leave the dead people dead and live in the present – using your memory to re-live the past and your imagination to pre-live the future!

      Have you watched “De Ja Vu”? This question totally reminded me of that…I spent ages drawing a diagram of parallel universes and different causes and effects after watching that and the more I worked out the more confusions I came across!! 🙂