Time travel theoretical possible!

New model 'permits time travel'
Researchers speculate that time travel can occur within a kind of feedback loop where backwards movement is possible, but only in a way that is "complementary" to the present.

In other words, you can pop back in time and have a look around, but you cannot do anything that will alter the present you left behind.

The new model, which uses the laws of quantum mechanics, gets rid of the famous paradox surrounding time travel.

Paradox explained

Although the laws of physics seem to permit temporal gymnastics, the concept is laden with uncomfortable contradictions.

The main headache stems from the idea that if you went back in time you could, theoretically, do something to change the present; and that possibility messes up the whole theory of time travel.

Clearly, the present never is changed by mischievous time-travellers: people don't suddenly fade into the ether because a rerun of events has prevented their births - that much is obvious.

"You go back to kill your father, but you'd arrive after he'd left the room, you wouldn't find him, or you'd change your mind" -- Professor Dan Greenberger, City University, New York

So either time travel is not possible, or something is actually acting to prevent any backward movement from changing the present.

For most of us, the former option might seem most likely, but Einstein's general theory of relativity leads some physicists to suspect the latter.

According to Einstein, space-time can curve back on itself, theoretically allowing travellers to double back and meet younger versions of themselves.

And now a team of physicists from the US and Austria says this situation can only be the case if there are physical constraints acting to protect the present from changes in the past.

you can read the complete article at : news.bbc.co.uk...

Isn't this theory mearly stating that if we were to go back in time, that the laws of cause and effort would come into play. Also how come going back in time cause us to go against what we were meant to do, unless there of course was some connection with our conscieces and the universe.

Could be, it is rather weird that if you went back, your father (if you had the intentions of killing him) would have left the room just before you'd arrive , or you'd change your mind, but if I went now back in time, and I knew I would change my mind (because now I know that it would happen), and fight againt it, or try to ignore it, and i'm trying to kill him, can he die? Because the fact he isn't supossed to die, maybe my knife (or bullet or whatever) would just pass trough him, or his wounds would heal within the second, or he's just as hard as a rock and a knife or bullet doens't affect him. So assume if my theory is right and you went back In time, no-one in that time could die (maybe except yourself) (but offcourse, the chance of me being wrong is big)

[edit on 20-6-2005 by Martini]

[edit on 20-6-2005 by Martini]

I saw this in the news. Major coolness! I'm excited about the
theory and I think it's very plausable. I'm looking forward to
'going back' sometime in my future. (did ya' follow that?)

Yeesh how many theoretically possible time travel models do we have now? It must be in the Hundreds by now, but personally I think that the energy requirements will be prohibitive for some time to come. Maybe in a couple thousand years of constant technological improvements it may be possible but I wouldn't hold my breath

why won't you find your father, and why is it impossable to kill him?

Originally posted by bushfriend
why won't you find your father, and why is it impossable to kill him?

Two probable reasons.

1) Time travel by humans is impossible because we are not on the quantum level.

or

2) Because there is no such thing as free will and everything we ever think or do is already set by the laws of nature. Free will is an illusion.

Personally, I think the reason is #2.

or #3 Every Descision we make or potentially make creates a new reality so if we say go back and kill our father we would still exist as all we would do is create a new timeline, i think that is much more plausible IMHO

Originally posted by sardion2000
or #3 Every Descision we make or potentially make creates a new reality so if we say go back and kill our father we would still exist as all we would do is create a new timeline, i think that is much more plausible IMHO

Its irrational. As much as physicist pull alternate realities into the picture, there isn't any evidence for them.

Which is more logical, that a human brain is a physical thing ruled over by physical laws, or that our actions are totally free and we can generate new universes.

Your version even contradicts the original article in that there are alternate universes when it is specificly talking about traveling through time in a single universe.

Its irrational.

Maybe, maybe not that's your opinion nothing more. I'll be sure to ask a physist on what he thinks about this and get back to you as I'm not really qualified, just throwing out possiblities, just because you think it's irrational doesn't make it irrelivant. Actually the Double Slit experiment is evidance, flimsy yes but it is evidance nontheless. How does a single photon enter one slit yet a wave pattern appears behind it? Hmm? If you can answer that question with absolute certainty then you'd be the next Einstein, but as it stands it's just all speculation on your part as well as my part.

Having No Free Will is irrational to me and that's my opinion and we are both just as likely to be right at this moment in what we call time.

Originally posted by sardion2000
I'll be sure to ask a physist on what he thinks about this and get back to you as I'm not really qualified, just throwing out possiblities, just because you think it's irrational doesn't make it irrelivant.

I'm a physist. Well ex-physist. I used to do grant-based research while teaching a nice state school and worked for NASA/JPL for awhile.

And your opnion is not irrelivant at all. Most talk of time travel is irrational at its core any ways.

Actually the Double Slit experiment is evidance, flimsy yes but it is evidance nontheless. How does a single photon enter one slit yet a wave pattern appears behind it? Hmm? If you can answer that question with absolute certainty then you'd be the next Einstein, but as it stands it's just all speculation on your part as well as my part.

Based on M-theory this is caused by photon interaction with other particles in dimensions we can not see. The same goes for gravity. I'm no Einstein.

When i say dimensions i mean the 7 physical ones we can't see, or possibly even overlaping branes, not alternate realities.

well if we can go back and not change the future or present by eather making another time line or somthing similar we might just have solved all our problems.... think about it.... I mean really think about it..... If we gain acess to the past or parrelel world or time lines what ever and it has no effect on the present? What could we do for example? set up colony worlds... if we go back before man existed the hole world would be freash and new and we could ship people there to start living.

2. waste/supplys go back in time and dump all our wast on one world/time/what ever and go back to others and mine/drill for oil what ever and ship it back to the present.

3. bring back extinct animals

because of how it would work you would have endless worlds to explore/explot.... example hay kids lets go visit granny she is living in 1799 at 5:45 pm the only problem i see is if you make a new time line how do you access it once you have made it unless you are forced to keep a gateway open bettween them to keep them linked.

there is still alot of problems with time traval but if you could get it to work for people it would solve all our problems if we are unable to affect the present.

'm a physist. Well ex-physist. I used to do grant-based research while teaching a nice state school and worked for NASA/JPL for awhile.

Cool Never knew that about you You just don't talk like it(eg not enough incomprehensible math in your examples )

Based on M-theory this is caused by photon interaction with other particles in dimensions we can not see. The same goes for gravity.

Most Physist's I have talked to think M-Theory is silly, I think it's increadibly elegant even though I don't understand it(the Math that is) but then again I don't understand the math of well any theory just a pure layman here.

I'm no Einstein.

Hey you never know Keep up the thought experiments you might get lucky one day

When i say dimensions i mean the 7 physical ones we can't see, or possibly even overlaping branes, not alternate realities.

Well we don't know, I would love it if in my life-time a Unified Field Theory was penned out and confirmed(sort of that is, in order to proove it we would have to recreate the universe and that would be a bad Idea IMHO :roll

PS When I hear Irrational, I take that as Irrelevant. Maybe I'm just way too tired now having been up for 30 hours straight Off to bed with me.

Maybe we are looking at this all the wrong way. Everyone is saying that if we did go back and do something that it would stem new realities etc...But wouldnt the most plausable theory be that, if you were capiable of interacting with something in the past, then resultantly you would cause an effect, but this effect would be the correct thing to do, since it was you in the first place that caused the timeline to be shaped as it is.

Think about the film timeline, its that kind of theory I am specaliating.

The other theory that I can come to the conclusion of is, that we mearly do not have enough information too truely create a theory about time travel.

Originally posted by Quest

I'm a physist. Well ex-physist. I used to do grant-based research while teaching a nice state school and worked for NASA/JPL for awhile.

...and I am an english major lol. It's spelled physicist.

THE ANSWER “Isn’t that kind of big?”
The Universe can just 'be' is because in the fourth dimension (We are in the 3rd) all time is one, and so everything already is and has been, that is how there is a god, and this god I believe created the 3rd dimension and time.

Maybe through a hole in the two dimensions was created to put chemicals into our dimension creating the Big Bang.

RIP THERY: I thought of an idea and then found it was already used, if space is the same density through completely then if it keeps stretching like this than it will rip! Could this stretch time? I think so because of the Quantum Time Theory and distance (light time), that is passably how worm wholes are created, by stretches in space and so stretches in time (Time or Worm Wholes would have to be enormous though).

TIME MACHINE: In order to create a time machine you would have to compress distance in a box, put a needle inside of the box (MAKE A SLIT) and move it back and forth, creating a wormhole. If you were to put a seed inside of the box than it would grow rapidly.

Originally posted by Lucid Lunacy

Originally posted by Quest

I'm a physist. Well ex-physist. I used to do grant-based research while teaching a nice state school and worked for NASA/JPL for awhile.

...and I am an english major lol. It's spelled physicist.

Yes well, now you found my weakness. My verbal/language skills are below average, and I know average is already LOW.

My ability to even talk at a normal rate and clearly is hard, typing is even worse.

And get this, i left science for the business world. Talk about strange move for someone like me. I proof read document about 10 times before sending them out.

[edit on 20-6-2005 by Quest]

yes, How do explain the explosion of tech in the ancient world. They did not develop these things all by themselves. They were taught by visitors from other worlds, and they came here using worm whole technology.

Originally posted by bushfriend
why won't you find your father, and why is it impossable to kill him?

Because its a loop and you already did this and it failed. If you had of succeeded, Then you wouldnt be there to be going back to kill him. Even if those were your intentions, when you came to do it it didnt happen for one of the reasons or possibly another. Does that make sense to you? Thats how i took it anyway

[edit on 6/23/2008 by Matt.Trakker]

I think God said I am the alpha and the omega. There is no traveling back in time or forward in time. The past/present and future are now happening at the same time. The illusion of time is a human concept.