I have no heart!!
Can someone please explain the grandfather paradox and is there a way around it
Excellent!!!!!!!!Basically, it's one of the contraddictions (=paradox) that emerge if you theoretically allow for time travel. That is, it would make time travel seem theoretically impossible, rather than physically impossible. It's one way of saying "even if there was magical or science-based machine that could allow you to travel back in time, once you're there you would be able to do something that contraddicts your own existence, hence such machine can't exist".
The paradox is summarized thus:
Suppose you build a machine that allows you to travel back in time. You use it, and for some reason intentional or not, you kill your own grandfather. Now that your grandfather is dead, you never existed... but if you never existed, who went back in time to kill your grandfather? No one. But if no one kills your grandfather, then you're born, and you go kill him. But if you kill him, you won't be able to back and kill him! See where I'm going with this?
Now, there are some ways to see past the contraddiction, but they're flimsy.
One would involve the creation of an alternate timeline, one where the world goes on without either you or your grandfather, and one where you travel back in time, and have no future after the present time you leave with your time machine.
Another approach would be more subtle and would involve a "stable" time loop, where you go back in time, kill your grandfather, and nothing happens. Puzzled, you take your time machine back to the future (I cannot believe I just typed that). And you notice that nothing has changed in the future, either! Eventually you discover that your time-travel adventure was always instrumental to creating the present you already knew, and the only thing that changed is your perception of it, that is to say, you learned about things you didn't know. Perhaps, that you had been adopted. Or that your grandma was already pregnant when you killed your grandfather. Or other details. Still, a bit flimsy. What if you go back in time and detonate a nuclear warhead? That's hardly something you could've missed...
Then again you could argue that maybe a necessary condition for you to be able to operate a time machine is that you have enough moral fiber not to completely devastate anything. Eh, it's complicated.
You killed yourself-- not only did you come from a differeent time but a paralell universe as well--- so the person you killed couldnt travel in time in that particular universe- and u will still exist because you come from a different paralell universe!I remember this paradox I believe Einstein was the one who said anyway I first heard about it when I was in six grade I came to the conclusion that it was going to be a loop, since I have no idea about parallel universes were, but when I asked my brother he insisted that I was wrong and explained to myself they would both (grandfather and grandson) disappear at that instant.... long story short, so it takes me more than a decade before I could see that I a six grader had a stronger argument than his 10 year older brother.... yay.
I think a better paradox is "What will happen if you make a time machine that opened 15sec into the past at the same location. Then you take a gun and kill yourself 15sec in the past before you even turn on the machine." Who killed you?
That's actually a pretty good answer, it makes sense.You killed yourself-- not only did you come from a differeent time but a paralell universe as well--- so the person you killed couldnt travel in time in that particular universe- and u will still exist because you come from a different paralell universe!
You're thinking of the twin paradox. It's family-related, but grandpa's not involved in time-dilation phoenomena.If you travel at 4 times the speed of light for 25 years, you will end up at the other galaxy 75 years in the 'past'. If you get to that other far away galaxy and have the huge telescope, you can look at Earth and see it as it was 75 years ago. If you turn around and go 4 times the speed of light back for 25 years, 50 years will have gone past for the spaceship crew, but they would end up 50 years in the past...or would they? Would time go faster in one direction than in the other?.