Time Travel - Is It Possible? And If So What Would Happen...

If you went back in time and kidnapped Shakespeare, then it will always be that you went back in time and kidnapped Shakespeare, therefore what has happened will still have happened, although our perception of what has happened may alter, but we wouldn't be aware of it, because our perception will have altered, and therefore, due to the inevitability of all history, nothing will be perceived to be different to how it was before. Or the universe will explode in a flux of contradicitions. :-) * P * :-)

You wouldn't have to bother with an infinite number of monkeys. If you want to buy my book, visit my blog: http://whatisthisstrangeplace.blogspot.com/

Or… Shakespeare finds his way back to his own time and becomes the finest 16th century writer of sci-fi drama? Incidentally, Iceman, I was just wondering, have you read anything by Jasper Fforde? I’ve only read a couple of his, but I don’t know of another writer who cleverly and humorously weaves classic literature with time travel and all sorts of other SF gubbins. :-) * P * :-)

If you kidnapped Shakespeare, you'd still leave Marlowe, which might finally solve that argument. Except it'd probably just turn into 'Who really wrote the plays of Arthur Boggins? Was it Christopher Marlowe?'

Er... was he kidnapped before he shagged Anne Hathaway? If so, who got to deflower her? If not, did she post a missing person report with the local plod? Not that that would help, they were probably far too busy writing out tickets for all those who didn't clean up the horseshit their steeds left in the High Street to go looking for a randy writer with his doublet around his ankles.

if anyone can arrange it can you please ensure that he is kidnapped before he wrote King Lear, then I could discount it from my next essay.

I was poised to write a lengthy exegesis of the varying models of chronophysics as used in different works of time travel literature, but I just realised that: a) If I do, my head will explode b) There's a whole world out there

I feel that if time travel is posible that it could only be forwards into a possible future. If time travel into the past were possible it seems likely that someone in the future would have discovered how and travelled back to brag about it. Mind you it's possible that Blair and Bush are shape-changing, time travelling, aliens and Dr Who is due to turn up any time now :O)

I think if time travel can occur it occurs at death or perhaps birth.

Okay, look. Time travel per se is not possible. You'll just have to trust me. What might, some day, be theoretically possible, is to create an entropy-reversal device which, at the same time, shields the user from its effects. Said 'time pilot' or 'chrononaut' could then use the machine to effectively rewind the entire universe, whilst himself remaining unaffected. However, chronologically, this event would still be following 'time's arrow', it's just that everything would be running backwards - in essence, killing everyone and destroying everything through reverse-entropy. (adults shrinking into babies, going into their mothers, turning to foetuses, separating into sperms and eggs, and so forth, trees becoming seeds then the seeds disappearing inside other trees, the sun gradually leeching energy from the surface of the planet, the universe shrinking towards a big crunch, etc) By stopping this process at any stage, the chrononaut could emerge in an identical copy of 1866, for example, but they would not have travelled back in time per se, only 'rewound the tape' to that point, before recommencing recording. The future that they came from, and all the people they knew, even the technology that brought them back, would have been destroyed by the machine. It would essentially be a doomsday device with the side-effect of allowing something close to time travel.

Not convinced that reversing entropy would mimic time reversal Rokkit. It's a bit like presuming that reversing gravity would take us back to the Big Bang... it seems reasonable until you think about it.

Time IS entropy....and motion....so entropy reversal IS time-travel. That's excactly what you'd have to do. Problem is, once entropy is reversed, you'd have no memory of ever having reversed it anyway...because you'd be just as much part of the reversal process as the environment around you. Like Einstein said: there is no such thing as time - just events.

For once I agree with Tim. I think it useful (and more accurate than some of the fanciful notions that abound in SF) to think of the universe as a serial tape that is being recorded as we speak. One day it may be possible to revert in some way, perhaps as Tim describes, however the sequence or story once recorded is set. The reversal would be akin to rewinding and then replaying a video tape. That is not to say that I believe the future is exactly mapped out in every way. I do believe that the universe is being created in this thing that we call the present and by virtue of creation can go in any/many potential directions. At an individual level, I find it useful to know that all our moments, good and bad are forever interwoven into the fabric of the universe in the manner described above. There is a kind of permanence to that... once lived, we do live forever in that sense.... all it takes is to rewind the tape and there I will be typing this guff on the keyboard. My version of the afterlife (if pressed), is precisely that described by Tim, some how being separate from the process but being able to watch ones life story unfold in excriciating and squirmy detail... I know I may be forced to watch myself thus I try and remind myself to behave as best as I can whilst I still can... We are being watched! I supposed if pressed furthe, I will allow that God if he does exist is some kind of creature that can watch any portion of this tape he/she chooses to... thus he does know everything there is to know, however that is where it stops. He has no influence on how the universe unfolds... that is the premise of the living and chance inherent in complex systems. Well, it makes perfect sense to me anyhow. As Shakespeare put it: To be or not to be...

Exactly which form of entropy are you talking about that you believe equates to time Yan? http://en.wikipedia.org/wiki/Entropy_%28disambiguation%29 By the way have you read this? http://news.bbc.co.uk/1/hi/sci/tech/2135779.stm

Interested in this. If time is a tape that can be wound back, how can there also be free will? I believe in the tape thing essentially, and I believe we make our own decisions, but I think also that if you take any moment of decision making and replay it over and over, the decision would always be the same. I believe free will exists insomuch as I make my own choices, but those choices were/ are / will be the ones I was always going to make. Enzo.. www.thedevilbetweenus.com

I assumed he was tlaking about this one: Entropy is a supervillian in the game Freedom Force vs. the Third Reich. Obviously. Enzo.. www.thedevilbetweenus.com

Clearly, he wasn't "tlaking" about anything. Enzo.. www.thedevilbetweenus.com

A really great game Enzo! Yan, assuming that reversing entropy would reverse time is like believing that re-freezing melted snow would reproduce the original snow flakes. If you want to look into the past get your telescope out and do a bit of star gazing :O)

I must re-quote mykle... it seems reasonable until you think about it - a beautiful summation! (no offence intended, mykle...) :-) * P * :-)

I'll have to respectfully disagree, Mykle - if reversed entropy seems resistant to thinking about, that's because it's a state that would be impossible to directly experience; everyone caught up in the process would be having their memories and experiences systematically obliterated. It entails a reversal of *everything*, not just isolated laws. It's not true time travel, but if the machine could genuinely reverse all universe's laws, then your refreezing a snowflake analogy becomes inaccurate, since it recreates not only the processes, but the identical surrounding conditions. 'Problem is, once entropy is reversed, you'd have no memory of ever having reversed it anyway...because you'd be just as much part of the reversal process as the environment around you.' Which is why I said our hypothetical entropy-reversal machine would have to somehow shield the user (and itself) from its effects.

I must say I can't see why reversing entropy reverses all the universe's laws Rokkit but, even if it did, it still presumes that there is no randomness. It is still believed that all information is lost or destroyed on entering a black hole so it's difficult to see how they could reverse and it's impossible to guess what effects the inevitable randomness would introduce... Mind you, it's a fun idea that you can go back to what is essentially an earlier time without actually going back in time and it avoids a lot of problems :O)

Hey, are you having a physics argument without me? No, I see your not.

Well, I meant it more as a thought experiment than an actual blueprint for a time machine, but yes, it's interesting what you say about black holes. That could be very cool, though. I mean, what would a reverse black hole be like? Perhaps it'd start spewing out a load of random stuff!

Anyone who is interested in the complexities of being an observer moving forward in time on a world that appears to be moving back in time should watch Backwards from Red Dwarf III. Part of the bonus material is Backwards forwards :O)

Entropy wouldn't reverse universal laws...laws are constants...they can't be reversed. Time is not a constant, a law, a nothing...it's a combination of phenomena (entropy and motion) that gives us a SENSE of time. Must be clear when speaking of time or might be contrived. The egg splatters but doesn't unsplatter. That's increased entropy. If you could unsplatter the egg then you are time travelling..but as well as the unsplattering of the egg you would be decreasing the motion and entropy of the whole environment..including your whole physical/mental states....to the point where you'd end up with the unsplattered egg but no memory of what the hell you were doing in the first place. Not possible.

Yan - I've just rewound the thirty seconds I wasted reading your garbled attempt at explaining the mysteries of the universe, and I'm going to spend it being nice to my cat, instead.

The only theory with any backbone regards time travel is the multiverse theory which would avoid paradox...which leads us into the realm of quantum mechanics...and cats would you believe! As for the past and the future - they don't really exist...only in memory and, as a result, contemplation of motion and entropy of a "future." All we have is a now which is hard to fully comprehend due to the necessity (for survival) for our brains to pan out reality the way it does. hence the saying: time is the mind's prison. Mykle: to answer your question regards which entropy I am referring to in relation to time - it's well written that entropy (and it's tendency to increase...as with the splattering egg analogy) is what physicists call "time's arrow." As in: our perception of time having a direction is simply due to our cosmos increasing in entropy (wearing out/trading energy) and not vice versa. Check second law of thermodynamics! Or http://www.tardyon.de/time.htm

If I could go back in time I would tie Iceman's hands behind his back to stop him starting this incredibly dull and pointless thread.

Yes, I would recommend spending time (in either direction) being nice to your cat. Last night, I turned to find my cat (daft old, gormless but happy, do-I-really-have-to-get-off-your-lap Sharon) staring at me. She was glowering. It was chilling. In eighteen years, the only expression that cat has ever worn, has been a blank one. I had to take her to the cattery this morning – but there was no evidence to tip her off about that last night. She growled and hissed at me when I put her in the travel box too and she’s never done that before. I’m beginning to wonder who she is the reincarnation of and what it is I’ve done to really piss ‘em off…