Verified answer

See: Quantum Suicide/Immortality (Google it). Using Schrodinger's Cat as an example: There is another way to describe the outcome: The cat is NOT alive and dead at the same time. Rather, under Many Worlds Interpretation of Quantum Mechanics (Which works just as well as the Copenhagen Interpretation that says the cat is alive and dead at the same time until we open the box and observe the cat.) Soon as we close the box, 2 universes are created. In one universe the cat is alive. In the other universe the cat is dead. Both universes exist. When we open the box we find out which universe we live in. BUT, the other universe continues to exist. The cat can never die, there will always exist a universe where the cat is still alive.

For your grandfather, there will always exist a universe where your attempt to kill your grandfather fails. Thus, the paradox is resolved, you live in the universes where your attempts fail and your grandfather lives.

You cannot kill your grandfather, you live in the universes where you failed. Thus, the paradox is resolved and time travel to the past is allowed.

Ray Bradberry used this plot device in his short story "Sound of Thunder" Mess with the past and you snap to the time-line that results from your messing with the past

http://www.lasalle.edu/~didio/courses/hon462/hon46...

Of course, there are other reasons like the 2nd Law of Thermodynamics that prevents time travel to the past.

It doesn't solve it. It puts the lie to the multiverse theory:

- you go back into a parallel Universe's past, and kill the grandfather of your parallel self

- of course he went back and killed your grandfather (since there are an infinite number of parallel Universes, one of them killed your grandfather).

Still a a paradox. Still violates conservation of energy.

You need to do this? Cross the event horizons of four or so successive supermassive black holes, and you end up back at the beginning of this Universe. The wait for Earth to form and cool, then wait for your grandfather to be born...

Of course it is a different Universe, same Props, just a different Script.

The grandfather paradox relates to the fallacy that we could move to another point in time with our memories intact. The parallel universe fallacy gets around the problem by allowing you to kill your grandfather in another universe, but not in the one where you were born.

Time is a property of the universe. We pass through it at what to us appears a uniform rate. We know that we can speed up or slow down the passage of time and one day it may be possible to pass backwards and forwards through it. However, that would not take us in our present state to another time. It would simply be like jump to another part of the DVD. If you could go back a year, it would still be the same you a year younger. You would have no memory of the ensuing year and you would live it in exactly the same way. If your time machine went back to before you were born, you would not be in it. Similarly if it went forward in time, you would arrive with a memory of that time you skipped since you would have existed in it. In fact we may be travelling backwards and forwards in time at the moment and not realise it.

maybe when you kill your grandfather and come back to the present, you come to a universe in which your grandfather wasnt killed..that is your attempt had failed..maybe you just get transported to an alternate universe if you misbehave with time travel... who knows

http://whatzzin.blogspot.in/2013/06/time-travellin...

I don't see something strange.Today hardly all yours grandfathers have killed yet. Just as their peoples around them. Do you think they had killed one another? Answer is no. Task is to survive you themselves now. You will understand soon that.

1st thing to learn in physics is that you cannot regard ANYTHING as "law" cos tomorrow the "law" may be proved wrong (or more likely incomplete)

It happened with gravity and it can happen with any law