Is Time Travel Possible and How Do Parallel Universes Work?

[dagg3r]

I'm new to the topic of theoretical physics so can someone fill me in is it possible to go back in time and go to the future?

because say Joe is from the future, and he goes to the pass and kill's his younger version. will he instantly disappear?

oh yeah btw, it struck me, parallel universes, how do they exist?

 

[newton1]

Originally posted by dagg3r
I'm new to the topic of theoretical physics so can someone fill me in is it possible to go back in time and go to the future?

because say Joe is from the future, and he goes to the pass and kill's his younger version. will he instantly disappear?

oh yeah btw, it struck me, parallel universes, how do they exist?

the Einstein's theory of relativity show me the time can't move back
so i think go back is impossible
but go to future is possible
because when you moving with light speed
your time will stop, and you will be live 1000...year
this is future

 

[LogicalAtheist]

1. No, it is not possible to travel through time. It is completely and totally impossible, it's just a sci-fi idea that will NEVER happen. That's that.

2. If you want to see proof of parallel universes I URGE YOU to go to the store and get the newest copy of SCIENTIFIC AMERICAN which says in big letters PARALELL UNIVERSES on the cover. It's about 6 bucks and WELL WORTH IT. It's amazing how easily it is to prove they exist.

 

[avemt1]

the Einstein's theory of relativity show me the time can't move back
so i think go back is impossible
but go to future is possible
because when you moving with light speed
your time will stop, and you will be live 1000...year
this is future

Time travel is only based on reletivity. That may be useful in normal situations, but is this a normal situation? We are talking about reversing all of the reletivistic veiws to point in the opposite direction of what they were before. This is what I call 'total time dialation.'
Another way to change time is to slow your 'time experience' to make the reletivistic veiw of everybody around you move faster and, basicallly speed up their time reletivistically to your time field.
this is what I call reletivistic time dialation.

 

[Mentat]

Originally posted by dagg3r
I'm new to the topic of theoretical physics so can someone fill me in is it possible to go back in time and go to the future?

because say Joe is from the future, and he goes to the pass and kill's his younger version. will he instantly disappear?

oh yeah btw, it struck me, parallel universes, how do they exist?

No, it's not possible. See the first post in: Why We Can't Go Back

 

[LogicalAtheist]

Heh, yes mentat says it all! I like mentat, good discussion 1 on 1 and he points it out so simply! yay!

 

[LogicalAtheist]

I use logic et al to explain my theories and facts. But I'm going to make a special exception and make a point, I will also post the common rebutal. NOTE, the rebutal is fine, but no need as I am just pointing this out.

Let's make the non-controversial (unless your a religious idiot) that the universe is oh let's say 50 billion years old.

Let's make another assumption, since people here like to pull stuff outta their butt, that there's only THIS universe, ok?

Ok. Now, practically speaking, if we have gone 50 bill years here, and we have oh let's say an infinite amount of time left. Then, even if time travel was discovered in 100 billion years, you telling me we wouldn't have future organisms popping the hell up all over the place?

They would have billions of years to choose all sorts of time periods and places to go.

It's just a practical idea.

The usual rebutal is, how would we notice something from the future. Well, would you notice if an 8th century warrior was walking around the freakin mall, going crazy over what he's seeing? I thought so.

Just a point. time travel possibilities have slready been disproven beyond rationality, thus and only thus i point this out for entertainment.

time travel is pseudo science.

 

[RuroumiKenshin]

Originally posted by dagg3r

because say Joe is from the future, and he goes to the pass and kill's his younger version. will he instantly disappear?

In a quantum parallel universe, his younger version is alive and not alive. This is called super-positioning. When he kills his younger version, the older Joe creates a new history.

oh yeah btw, it struck me, parallel universes, how do they exist?

Which parallel universe?


Level 1: I'll get back to you on this one...
Level 2: When the universe inflates, some parts of space stop stretching. The symmetry on that region would break, therefore creating a new bubble like universe with a Hubble volume that is identical to the original universe. But the events aren't the same.
Level 3:The quantum universe. In this universe, everything is random. Events branch out according to each event. For example, if you choose a salad out of 6 choices, you are only experiencing the 1/6 of the whole reality. There is one wave function per reality. In another quantum history, you didn't have a salad and so on. So, you did have salad and you didn't have salad. This is called supperpositioning.
Level 4: In this universe, all physical laws are not consistent with ours. In such a universe, what we think of gravity is exactly the opposite in the Level 4 universe. Time could be a physical aspect of our universe that we can control easily and naturally.

Scientific American has an article on this, if you want to read it.

 

[LogicalAtheist]

Majin - Yeah this article was recommended by me and others, it's good. I want to learn more about it I'm going to get the elgant universe..

 

[Ivan Seeking]

In the collection of essays, "The Future of Spacetime" by Hawking and others, Igor Novikov presents a rather interesting proof. I have not seen the formal derivation of this but I understand that one does exist. The setup is to consider a billiards table with a time machine located in the corner pocket. If we shoot a ball into the corner pocket, the ball falls into the time machine, goes back in time, and is then released from the side pocket just in time to hit itself; thus deflecting it's original trajectory and preventing the ball from ever falling in the corner pocket - a billiards version of the grandfather paradox. It can be shown that it is possible to cause the ball to deflect itself, but not so much as to miss the pocket.

Edit: Hawking [I think] then comments that one might go back in time to kill their grandfather, but the laws of physics would conspire to deflect the bullet or the thrusting knife.

For you multiple universe fans out there, could this still be consistent with the many worlds theory in that all possible paths exist, but only those allowed by this solution?

 

[LogicalAtheist]

Ivan - that idea can quickly be debunked. It's just one science fiction idea of how time travel would work.

Nevertheless, time travel still remains completely and totally impossible.

 

[Mentat]

Originally posted by LogicalAtheist
Heh, yes mentat says it all! I like mentat, good discussion 1 on 1 and he points it out so simply! yay!

If there is sarcasm implied in this, I've missed it, and I thank you for the apparent compliment.

 

[Mentat]

Originally posted by Ivan Seeking
In the collection of essays, "The Future of Spacetime" by Hawking and others, Igor Novikov presents a rather interesting proof. I have not seen the formal derivation of this but I understand that one does exist. The setup is to consider a billiards table with a time machine located in the corner pocket. If we shoot a ball into the corner pocket, the ball falls into the time machine, goes back in time, and is then released from the side pocket just in time to hit itself; thus deflecting it's original trajectory and preventing the ball from ever falling in the corner pocket - a billiards version of the grandfather paradox. It can be shown that it is possible to cause the ball to deflect itself, but not so much as to miss the pocket.

Edit: Hawking [I think] then comments that one might go back in time to kill their grandfather, but the laws of physics would conspire to deflect the bullet or the thrusting knife.

For you multiple universe fans out there, could this still be consistent with the many worlds theory in that all possible paths exist, but only those allowed by this solution?

This illustration (of the billiard ball) is interesting enough to discuss, but it is not even an hypothesis. An hypothesis must be testable (at some future point). This is not only untestable, but utter (obviously fictitious) nonsense.

 

[Ivan Seeking]

Originally posted by LogicalAtheist
Ivan - that idea can quickly be debunked. It's just one science fiction idea of how time travel would work.

Please do so. [?]

 

[LogicalAtheist]

Mentat - it's a compliment, I'm never sarcastic, I'll just say it if I mean it.

 

[Ivan Seeking]

Originally posted by Mentat
This illustration (of the billiard ball) is interesting enough to discuss, but it is not even an hypothesis. An hypothesis must be testable (at some future point). This is not only untestable, but utter (obviously fictitious) nonsense.

Why do make faith arguments in a scientific discussion?

 

[Mentat]

Originally posted by Ivan Seeking
Please do so. [?]

You mean, debunk the idea? Did you happen to read the first post of the link I provided?

 

[Mentat]

Originally posted by Ivan Seeking
Why do make faith arguments in a scientific discussion?

I'm not making a faith argument. I made a simple, scientific, argument against the idea of backward time travel in the link that I provided (above). I call the illustration nonsense because it relies on something that cannot (unless my reasoning in "Why We Can't Go Back" fails) happen.

 

[Mentat]

Originally posted by LogicalAtheist
Mentat - it's a compliment, I'm never sarcastic, I'll just say it if I mean it.

Good point, I've noticed that about you.

 

[wimms]

Originally posted by Ivan Seeking
Edit: Hawking [I think] then comments that one might go back in time to kill their grandfather, but the laws of physics would conspire to deflect the bullet or the thrusting knife.

Ahh, now I know where all our conspiracy theories originate from. Its those bastards from the future...

 

[Ivan Seeking]

Originally posted by Mentat
You mean, debunk the idea? Did you happen to read the first post of the link I provided?

Surely you realize that this is proof of nothing. What you present is a logical conundrum. Many paradoxes exist regarding time travel. Perhaps we will find good reasons that such things are not possible, but to draw conclusions at this point is merely speculation. If Hawking, Novikov, Ferris, Lightman, Price, Whitten, Gell-Mann, Wheeler etc etc cannot agree on this question, then why do you make such a bold assertion?

 

[Ivan Seeking]

Originally posted by wimms
Ahh, now I know where all our conspiracy theories originate from. Its those bastards from the future...

No, but that's what the time travelers from the past want us to think! Don't be fooled!

 

[LaplaceOperator]

Then, even if time travel was discovered in 100 billion years, you telling me we wouldn't have future organisms popping the hell up all over the place?

That depends on where you are looking.

IF time machines are possible, they will be a very formidable devices: Gigantic dense structures which bend space and time. You won't be able to build these things near the Earth (unless you wish to tear our planet apart with tidal forces). So unless you look far out into space, don't expect to see any time traveller arriving from the future.

The usual rebutal is, how would we notice something from the future. Well, would you notice if an 8th century warrior was walking around the freakin mall, going crazy over what he's seeing?

Will you recognize such a person as a time traveller? Or will you simply consider him to be a mad man who merely thinks himself to be an 8th century warrior?

Perhaps there are countless time travellers right under our noses, and we simply don't recognize them for what they are? Most of them, undoubtly, succeeded in concealing their true identity (a wise move in our day and age). And those who didn't are probably locked up in some looney bin, along with the people who "exposed" them.

Just a point. time travel possibilities have slready been disproven beyond rationality, thus and only thus i point this out for entertainment.

No it hasn't.

Your argument doesn't stand. And I've also rebutted Mentat's argument as well (see his thread for my rebuttal)

 

[Nomy-the wanderer]

It's not impossible to tarvel through time, just u can only travel forward...
If we r dealing with time as a dimension and not constant, ofcourse we can...
A spaceship travels through light years, and one traveling with a speed close to the light's with my twin, then my twin will definitely be younger when he gets back on earth, he's going to be younger than me, yeah he has skipped several years and came back to the future...

It is such a paradox..

The only problem with that is that u need an infinite amount of energy to travel with such a speed...