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New Model Solves Grandfather Paradox
goldfishy writes "If you went back in time and met your teenage parents, you could not split them up and prevent your birth - even if you wanted to, a new quantum model has stated. 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 theory, you could go back in time and meet your infant father but you could not kill him." From the article: "Quantum behaviour is governed by probabilities. Before something has actually been observed, there are a number of possibilities regarding its state. But once its state has been measured those possibilities shrink to one - uncertainty is eliminated."
I am my own grandfather!
What does this mean for Fry and his past-nastification?
Free of Flash! Free of Flash!
Farnsworth: Oh, a lesson in not change history from Mr. I'm my own Grandpa!
You become your own grandfather.
In C++, friends can touch each others private parts.
How can that even be remotely possible? Anything and EVERYTHING (no matter how small or big of an event it is) will change SOMETHING in the future. Anyone who thinks any differently needs to go back to school.
Sounds like the Novikov self-consistency principle to me.
Please, for the good of Humanity, vote Obama.
Just watch Quantum Leap
"OK, McFly, here's the gun. If you can kill your own father and thus erase yourself from existence, we'll know the theory was wrong."
Lawrence Person (lawrencepersonh@gmailh.com (remove all "h"s to mail)
http://www.lawrenceperson.com/
Behold! This was posted in the past!
I can't help but think this article is flawed pseudo-science with little actual evidence to support this theory. The 'universe sorts itself out' theory is all well and good in something like the hitchhiker's guide to the galaxy, but to present it as science seems a little dubious.
this was a principle plot point in the move the time machine.
How does this "solve" the grandfather paradox? This seems to just be re-stating the problem. We already KNOW that if I can go back in time, I can't kill my grandfather. So what is new in this article?
In other words, even if you take a trip back in time with the specific intention of killing your father, so long as you know he is happily sitting in his chair when you leave him in the present, you can be sure that something will prevent you from murdering him in the past
This means that you cannot be killed when you go back in time, nor can you kill or destroy anything! That's just perfect!!
Go back in time and be able to observe, only... no ability to interact with anyone either... it should be kinda like ghosts... we go back in time and observe and be like ghosts in the sense that we cannot interact and change anything that has already happened but only observe!
Imagine the possibilities of history classes of the future... maybe there are already a lot of ghosts watching us right now... the future students studying history!!
How do you know they're not me?
For all I know, it's totally possible.
But highly unlikely.
The question is - if you exist in the same timeline as yourself at a different age - wouldn't the cells in your body have been replaced atom by atom over time anyway?
So what if I exist here in Seattle and in China at the same time.
-- Tigger warning: This post may contain tiggers! --
....Huh?
"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."
That's not clear at all. If I went back in time and killed the baby George W Bush, it's like he would disappear in the middle of a speech. Rather the entire course of history branching from that moment would be changed, so that in the "present" no one would ever know GW had existed.
-Alex
Couldn't you go back in time to kill your grandfather, only to have him rematerialize out of quantum randomness 5 minutes later? It's not impossible, just really improbable... maybe that's the protection mechanism.
One great big unscientific cop-out;
"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," said Professor Greenberger.
Sounds more like 'faith' to me.
In the free world the media isn't government run; the government is media run.
Comment removed based on user account deletion
Consider the event "I have never gone back in time."
There are no karma whores, only moderation johns
"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," said Professor Greenberger.
Anyone else having difficulty imagining a scenario where it would be "impossible" to kill somebody?
I mean sure, there could be the above difficulties - but short of a divine miracle, what could possibly stop (for example) a determined psychopath from doing everything possible to kill his own father?
...Also, I didn't know Buggalo could fly.
stop picking at our simulation, or we turn it off.
final warning.
love,
the operators
Another example of logic gone awry. If the number of possible states has been reduced to one, then time travel is again impossible. Not only can you not kill your father, you can't meet him either. You can't be anywhere at all in the past because you weren't there.
This sounds a lot like that John Titor character. http://www.johntitor.com/
Not only could you not kill your father, you could not change any event to which you or anyone else had observed and recorded. Essentially this is the 12 Monkeys interpretation of time travel, you are only to observe.
"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."
Why is this obvious? For all I know this might be happening. How do I know the immediate past is truly as I recall it and hasn't 'changed'?
So they are saying the past is deterministic (since the quantum state has already been resolved). But surely that means that since there was no state in the past determined in which your forefather met you, you can't go back to meet him, since that state does not exist.
You just ruined my weekend...
If I went back in time, and killed my mum, I wouldn't have been born to go back in time to kill my mum?
So she wouldn't have died, leaving her to eventually give birth to me, for me to go back in time and kill her, preventing her from getting pregnant with me, meaning I would never have existed to go back and kill her?
Where's the paracetamol, mum?
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.
;)
So either time travel is not possible, or something is actually acting to prevent any backward movement from changing the present.
So let me get this straight, BBC reporter. Your proof that time can't be changed, is simply that you don't remember it happening?
There are just so many flaws in that reasoning.
First, time changes could be happening everywhere, but perhaps you have not witnessed one. Wait! How about this? How about time changing, and altering your memory at the same time?
What's the matter with you? Do you believe that it is impossible for something to occur, without you being aware of it?
Is this a God complex?
What unmitigated self-importance, BBC reporter!
Now sure, I know this reporter was likely trying to parse some marlaky that they were told, but this has to be the worst use of logic I have seen.
So, I guess this makes the Terminator Series pretty much infinite then, since basically they've been trying the grandfather paradox against SkyNet all these years.
That and John Conner will apparently never die, at least from a time traveling robot.
In Soviet Russia, Trojan exploits YOU!
parallel world lines.. its you -2%
It's dead or is it alive. We don't know and we will never know. Perhaps it's lying in an semid dead/alive state. Perhaps there are multiple realities each one witha cat with a differnt possiblity. Damn if I know but the only way this article makes sense if you use the second model. In that case you probably would create a new realitiy with the slim probability that you went back and time and killed someone. Now I feel like bashing my head up against the wall because quantom mechanics makes no sense whatsoever.
Ooo man the floppy drive is broken. No wait. The computer is just upside down.
I knew those Terminator's would never kill John Connor or his mother.
Humans rule!
So does Anonymous Coward have good karma?
I much prefer the divergent timeline theory that states that if you go back in time and kill your father, all you do is split yourself off into a parallel time stream. You don't die, because you ARE alive. Your father in the original stream stays alive. If you return to the future though, no one in that timeline will know who you are because you were never born in that timeline.
I'm quite sure someone like Hawking will soon step in and say that though time travel of something is theoretically possible, that no intelligent being would be able to make the trip successfully because no information would be able to travel back in time.
"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."
Oh yes quite obvious!
Or not.
If you went back in time and changed the past, those in the future would instantly be changed and would have no reccolection of past events being different!
The one thing that always bothered me about those time travel movies (besides the ridiculous timetravel part) like "Back To the Future", is that you wouldn't have to go to extremes to prevent your birth. All you would have to do is bump into your Mom or Dad to delay them for 1 second; that slight change in the timeline would guarantee that it would be a different sperm that won the race to impregnate your mom.
Power to the Peaceful
There must be more here than it sounds, as this sounds like "once something has occurred, it has occurred, not something else." Well, duh. I didn't know that.
But it really proves nothing. I mean, if you go back in time and kill your grandparents, then you would never have observed their existence, so the basis of the paradox is removed, no? It's all just a rehash of whether time travel suspends logic.
Currently hooked on AMP
That means, the Roadrunner is the Cayote's daddy, Tweety bird is Sylvester's pappa, and GI Joe and Cobra are the world's most incestous family?
Egad!
Ryan Fenton
It could be happening all the time and you wouldn't be aware of it (by definition).
Sounds like bad fiction to me.Sounds like the techno-babble "justification" in the bad fiction.And the easiest way to not change it is for time travel to be impossible.If, for example, you knew a picture would be taken, you could reflect light from your body and appear in that picture, thereby altering the future.
So, travelling back in time, you cannot reflect light, and, by the same token, you cannot absorbe light.
And it just moves up from there for all other physical effects. Nothing touched, no air breathed, no light disturbed, nothing.
So, how would you even know you were in the past?
It says if you are 90% sure that you're father is alive you have a 10% chance of killing them in the past. What if we send someone who knows nothing about past events and tell them to say, kill Hitler?
Consider your whole existance as a time traveller as a probability function. Each possible path you could take has a probability of happening. Anything paridoxical has 0 probability, just can't happen. It's like seeing shrodinger's (sp?) cat dead and then going back to try and save it. The probability of anything that's happened and been observed is already 1, if you go back in time it'll still have been observed already even before it's technically happened, so the outcome is already determined and can't be changed.
If that made no sense it's probably because i'm stoned.
We all seem to assume that there is some sort of record of what has happened in the past that we can actually travel to.
What is keeping this record? Do you think that the past is happening again in another dimension, or something of that nature?
It's not as if it's a place you can travel to. By this theory, there wouldhave to be infinite seperate dimensions for each and every 'whatever the smallest measure of time is', because I doubt the universe uses anything so mundane as milliseconds or anything of that nature.
Where are we traveling to. How do we know that there is a past to go back to? We assume that since things have been done and we have recorded them as having happened, that the universe has as well.
I'm not so sure of that.
Just kidding. I was just traveling back in time to say hi to gramps when I decided to see how the "old" internet was working. let me tell you about the future:
- still lots of spam
- geeks still not getting laid
- cmdrtaco promoted to admiral taco.
But nobody is going to question it because it involves quantum mechanics... idiots.
Has anyone ever told you what a fine present you are? No, really, I've visited many moments in my life, and I have to say that 'now' is by far the finest. Two thumbs up, *way* up, for the current time.
FTA:
So, if you know the present, you cannot change it.
But as far as history knows you weren't ever there, and since you being there at all would change history, this would either disprove Einstein's general theory of relativity or the researchers that came up with this theory.
To avoid contradictions in time travel, two simple rules must apply:
1) You can observe, but not alter the past.
2) You can alter, but not observe the future.
That principle of quantum mechanics has nothing to do with whether time travel can alter the future. The key phrase in it is "has been measured". Yes, the person named Joe who is here right now's past is known and unalterable, but the Joe of five minutes ago, lacking five minutes of memories and air chemicals, has a clean future in front of him which has not been observed. They are two totally different Joe's, and may take two totally different paths.
Well, I, for one, will never enjoy a pasty ever again.
What about the parallel universes theory in regards to time travel? Does this mean it's no longer a viable possibility as well? I don't see how this article stated/proved anything new in regards to time travel and quantum theory that we hadn't already hypothesised.
You need to read "The Proteus Operation" by James P Hogan...
And excellent SciFi story on how time travellers change history (but actually are creating new time stream branches)
This "theory" is stupid, as it's impossible not to affect things in a different point in time. That is, everything we do affects everything else. The scale starts small, but becomes astronomical as it ripples outward. Therefore, the only sensible possibilty is that time travel creates a new, independent timeline.
1989...
Is this actually a new theory? Any forth grader who watched star trek could have figured this one out...
It's still hard to grok what this "prevention" means to the time traveller. If you go back, are you physically prevented from firing the gun or will the gun misfire? Or if you make a change, does the timeline establish a new universe with the old one running along merrily as a parallel universe.
When we use our senses, we only see things in the typical 4D realm, so is it possible that all those other postulated dimensions (to 11) give the degrees of freedom to allow bifurcations in the timeline? Geez this is confusing.
For those having trouble grasping it, it works kind of like this:
Say you decide you're going to the store to buy milk. You get in the car and start driving there, with the one thought in your mind being going to the store and getting milk.
On the way there, you get in a car accident. You never reach the store.
Stuff like that happens every day. Things happen that are out of our control and are impossible to predict. It's the same concept, just taking place in the past rather than the present.
In my story idea, I summed it as "Nature will right itself". It's not like people don't die random and unexpected deaths every day.
By necessity, since traveling backwards in time causes effects to occur before their cause. The universe stops making sense when causality is violated because causality is what makes the universe make sense in the first place.
Anyway, I think the authors may have seen this movie. The idea is certainly not new.
I'm not a journalist, but I play one on slashdot
They claim that you can still go back in time to observe the past. What I find to be the flaw is that while you're observing, you are still manipulating the environment around you.
You are causing molecules to move where they weren't there before. Let's ignore the whole killing your father nonsense, and go down into super detail.
The molecules of the present were in fact in their present location because of events that happened in the past. If you travel back in time to observe (thus rearranging molecules in the past), it's like saying that there is 0% chance that you can't change the molecules around you in the past, therefore stating that time travel is impossible.
It's either that or you can observe the past in some ghost-like state mentioned by other posters.
m y k a r m a i s m o r e p o s i t i v e t h a n y o u r s.
If you saw your buddy killed before your eyes, you would leave the scene immediately, and avoid examining the body in any way. Instead, you'd go get a dummy that looks like your buddy, then return to the time just before your buddy died, rescue him, and leave the dummy behind to "fool" your past self. I was delighted later on to see that in the game Chrono Trigger it was possible to use exactly this mechanism to save the life of one of the characters in spite of their onscreen "death".
fuck science
I came up with this kind of stuff from watching all the time travel movies when i was a kid in the 80's (terminator, back to the future, star trek, etc).
You know, the whole idea that you can go back in time and actually *change* the present...if you change it, then it's not the same present you came from...you either fullfill something you always had done but didn't know it yet, or you changed something and in-effect completely separated yourself forever from whatever 'present' you originated from...either way, you are either fullfilling or creating something new and separate, not changing the original.
I'm just wondering if I'm the only one who had thought this...it's really close to the research
Thank you Dave Raggett
It means you cannot travel into the past and kill people that were not killed in your future history.
You are fully capable of killing people provided that they were killed in your history.
You are fully capable of being killed.
This article is stupid. All this hinges upon the single valuedness of solutions to classical PDE's. Which hinges upon basic consistency. Physicists and mathematicians have known this since before GR was ever invented. This has almost nothing do with GR or QM. Only that GR can give you spacetimes with closed time loops. Whereas before you just pulled them out of your ass.
A time traveler cannot alter the past. The past has already happened. Any participation in the past has already occurred.
:-)?
A time traveler could go to the future and find out what will happen, but on return to the past he will be unable to alter the future - he has already seen it, so it has already happened.
Now, what is this paradox that has everyone so confused
Raise your children as if you were teaching them to raise your grandchildren, because you are.
If only someone would finally get me a flux capacitor for Father's Day.
. Ergo sum cogito - Yoda
If someone went back in time and killed Mrs. Gore, Al Gore would never have been born.
If Al Gore never existed, the internet would never have been invented.
And if the internet was never invented, then Slashdot would nev......
Microsoft's VP of Customer Service is Helen Waite. If you are having problems with their products go to Helen Waite.
*sigh*
When will they get it?
There is no such thing as time.
Time is not an object, interstellar fabric, or any other romanticized spawn of science fiction.
Time is but the way we use to measure movement, nothing more.
Disputes such as this are pointless simply because time travel is simply not possible.
I rest my case.
~You laugh because I'm different, I laugh because I'm insane~
even if we go there, we could introduce soem bacteria or virus that could change the course of time, maybe we step on a bug or eat a chicken who decendants were meant to feed thounsands of people in future years, any participation, even breathing could change the course of history
You were to kill your parent/garndparts ect you would not be born therefore you would not go back and they would live. So you would go back and kill them and such you have a loop.
I am a viral sig. Please copy me and help me spread. Thank you.
Apparently the BBC can report on this new model, but they can't seem to say where these papers are being published or what scientists are working on it or at which universities this research is taking place. Michio Kaku posited this might be the case in his book Hyperspace (excellent book) and to my mind, this is on the same level. It is defenitly some interesting stuff to talk about after burning a J, but it hardly rises to the level of scientific model. The Standard Model is a model; this is just fluff, albeit somewhat interesting fluff.
exceptio probat regulam in casibus non exceptis
Ok what if I don't kill him, I just chain him up and lock him in a basement for the rest of his life?
Even the mere observation of any event leaves. It is impossible to even look at the past world without absorbing light that will irrevocably change things. A basic rule of quantum mechanics is impossible to observe an indeterminate quantum state without "collapsing" it to a single possibility. Any observation of the past will change the present, unless there is some extraordinary quantum coincidence that takes the different state you leave the past in and transforms it to the present.
So accordingly, while you certainly can't kill your grandfather, you can't even see him! How exactly does this qualify as time travel?
This entire article seems exceedingly hard to verify without the actual science.
There's so many things wrong with the logic in this article, I don't know where to begin...
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
If someone did change the past, would people in the present know it? Can you test that hypothesis? If not then it is just conjecture.
It is as if, in some strange way, the present takes account of all the possible routes back into the past and, because your father is certainly alive, none of the routes back can possibly lead to his death.
If this statement is true then there is no free will (i.e. the events of the future dictate the events of the past as much as the events of the past dictate the events of the future).
"You wouldn't be able to kill him because the very fact that he is alive today is going to conspire against you so that you'll never end up taking that path leads you to killing him."
Only if the Universe itself is sentient.
It's said that the outcome of a quantum event is unknown until observed, and the act of observing controls the end state. Fine, but...one of the great mysteries of quantum mechanics is that an infinite number of probabilities at the quantum level always coalesce into precisely one predictable outcome at the macro level. Every time, no exceptions. Our whole study of physics is based on this assumption, else no test result could ever be relied upon. We know it happens but we don't know why. Are the infinite numbers of probabilities real? Or are they an illusion of something more fundamental? In order to show that quantum mechanics makes the past unchangeable, you first have to show how quantum probabilities produce the macro world around us. Until then, it is only wishful thinking.
The NSA: The only part of the US government that actually listens.
yourThat article said NOTHING new but killing dad reminded me of Oedipus.
Going back in time to kill your father is one order of time line interference. Sending your own angry mother to do it is more interesting.
But if your mom goes back in time to meet you while you kill your dad and conceives before returning to the present, what order of time line interference would that be? Will you and your mother give birth to...you? And can you watch???
One of the major problems encountered with time travel is not that of accidentally becoming your own father or mother. There is no problem involved in becoming your own father or mother that a broadminded and well adjusted family can't cope with. There is also no problem about changing the course of history - the course of history does not change because it all fits together like a jigsaw. All the important changes have happened before the things they were supposed to change and it all sorts itself out in the end.
Douglas Adams, The Restaurant at the End of the Universe
This is another case of science fiction being well ahead of science.
I often don't like the choices people make, but I like the fact that people make choices. That's why I'm a conservative.
Is this indirrectly arguing that free will doesn't exist? Let's say I go back in time and WANT to kill my father. What exactly would it feel like to not be able to?
so, in theory, someone could blow up earth, and then go back in time and change whatever they wanted, and it would all be fine so long as earth blows up in the end?
Then the past is only what we have recorded, so if we erase all records, there is no past right?
I wonder if that also means that there is something that got recorded wrong, it would be impossible to go back in time and change it?
UHHHHHHHH Dude, when are you talking about bumping
them to delay the sperm? eww.
Something I don't think a lot of people really grok is that the laws of physics are time symmetric (actually the full symmetry is CPT, charge+parity+time, an electron going back in time would be a positron for example) so the fundamental weirdness is why we perceive time to flow in one direction in the first place. That's why I've always loved Feynman's absorber theory and it's associated spin-off the transactional interpretation of quantum mechanics. Those theories don't discard the so-called "advanced" (that is, backwards in time)solutions and work out how in a universe with appropriate boundary conditions you get an arrow of time. The advanced solutions actually exist but because of the boundary conditions they cancel each other out except where they "count". So according to the theory, when you go to push an electron every other particle in the universe sends waves back in time in response to push back on the electron at the exact instant you push it! The advanced waves only manifest themselves as the normal radiation resistance we observe when accelerating charged particles. The transactional interpretation takes this line of thinking with regards to the collaspe of the wave function. When one particle of a two particle entangled system wave function collapses it sends an advance wave back in time to collapse the wave function of the other particle. So in the EPR experiment there is no instanteous "spooky action at a distance" but travel exactly at the speed of light but in the opposite direction in time.
He killed his grandfather, but fortunately he did the nasty in the pasty to correct the situation.
How could you not change the past? The simple fact you can breath in the past will change something in the future. How could one go back to past and avoid changing anything at all? One would just see the "light" emitted in the past, like a movie, without interacting to it?
Since the path of the raindrops are now a certainty, it would be like walking into machine gun fire since the path of every drop has already been determined. Therefore, if you travel back in time into that gentle summer rain, you'd be riddled full of holes.
Wouldn't you?
A goal is a dream with a deadline
Ok..so your grandfather might be off limits but what about his grandfather?? huh? ...bet they din't think of that one!!!.oh wait...
Siggy Sig Sig? Where is the sig?
Those people took until now to come up with this model? I thought that's how time travel worked in that Japanese manga, Doraemon, which was created in the '70s.
I pose a theory that if you were to go back in time and kill your parents, you would continue to exist in that timeline. However, if you were to travel forward into your normal time you would cease to exist. (ie POOF) Documents would never exist and nobody would remember you. Impossible you say? No. Think of it this way... pyschics are able to gain information from an event they personally have never experienced. To me, it would make sense that the opposite would be true; that we can lose information from an event that we never experienced.
Actually, the single probability of everything occuring exactly as it did grows to one. While the probabilities of other events occuring shrink to zero.
My favorite Asimov novel is The End of Eternity. The premise is that time travel exists, and a group of people outside of the normal fabric of time tries to slowly improve the existence of mankind by making tiny, tiny changes at key points in the timeline.
As explained in the book, a person would never know that a change had taken place. As per the book, it's possible that I might not have even existed last week, but maybe a Change willed me into existence, then I was created and have all the memories of my life like I actually lived it, even though I didn't. It raises some great issues about time travel, and for the true Asimov fans, he accidentally (on purpose?) and subtly ties the entire Foundation/Robots/Empire series together before he began explicitly doing so in the 80's. This book is a true prequel to those.
Terry Pratchett said it best when he said that you end up going down the wrong pant leg of the trousers of time...
Seven puppies were harmed during the making of this post.
That as long as you remain back in time, your father becomes unkillable... because if he was killed, you wouldn't exist?
The unofficial
... someone pass me the blunt; i want somma that shit too.
Seriously though, i do enjoy something that bends the mind in thought. Good deal.
Another fine example of how far reaching science fiction has basis in reality. Like Jules Verne, who wrote about an atomic powered submarine long before we harnessed the power of the atom, H.G. Wells wrote in The Time Machine about a scientist who invented a time machine so that he could go back in time and prevent his wife's demise... only to find out that no matter what he did to intervene, the ultimate outcome was the same.
Since you exist to go back in time, that bump into your Mom or Dad would actually insure that you would be born. See, once you've been born, it is impossible for you to go into the past to prevent that. It would create a paradox, and this is impossible (Dr. Brown would tell you that you could destroy the universe.)
In a limited way, a trivial case of this was proven. If you have a timelike wormhole (one end is in the past compared to the other). and you toss a billiard ball into the future end, there is _no_ solution for any arangement of the ball and the wormhole that allows the billard ball to intersect itself in a way that keeps it from falling into the wormhole in the future.
note, that there is nothing wrong with the ball being sent back in time, it just can't self intersect in a way that keeps it from going back in the first place, there just doesn't exist a configuration that allows this. However, there are solutions where the ball self intersects in such a way that _causes_ it to enter the wormhole. wacky stuff. how one would arrange such a thing is another matter.
That said, does anyone have a link to an original paper on this result? I mean, it is a common psuedotheory in physics, I am wondering if some new evidence has been discovered recently or a reporter was just repeating some noodling of someone partaking in mental masturbation.
http://notanumber.net/
Time travel?
How do we know the previous state of quantums? All trace's overwritten by current quantum's state so there is no time travel!
Time travel is fictional thing that came from the truth that we can remember the previous *LOGICAL* state of some kind of time, that is memory, but quantum itself does not have that kind of memory. Remember that we have the theory of butterfly effect that every thing affects everything so there is no portional time travel(i.e. Only I go back to the previous time) unless we rewind EVERYTHING but time travelers. And, can we rewind everything as in the movie Time Machine? Where the hell is the trace of the previous state? Remember that the state of quantum is all recursive.
How about going back into the past in passive mode? So it's not like you can walk around there, all you'll experience is yourself, back in time.
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The thing about time travel is that by nature, it has to be discovered simultaneously at all points in time. So, if we're not doing time travel right now, we never will. (At least random-access time travel. Someone might come up with a short term 'rewind' ala Superman or "Prince of Persia.")
The reason is...as soon as the first time machine is invented, then everyone from the future will jump back into the past and invent it first.
--Welcome to the Realm of the Hawke--
the outcome is probabilistic until measured. However, if your logic is followed to conclusion, only someone who has never had his presence measured in any way could travel in time in the first place.
....unless of course, you're suggesting that measurement must be by a human.
Thus, time travel is at least impractical and likely impossible, especially given that even the smallest insect can detect the presence of another life form.
A goal is a dream with a deadline
there you go...
http://www.arxiv.org/abs/quant-ph/0506027/
other theories suggest that while travling back in time is possible, that should you do so, you wouldn't travel straight back. In other words, you would end up in a parallel universe. This is supposedly a safeguard put into place by nature itself to prevent you from screwing up the entire timeline.
Time travel is not possible. Time moves forward for all of us. You cannot go back forward. You can go forward at different speeds though, so if you find a way to experience time slower or faster than everyone else, then you can 'time travel' in a comparative sense.
Choosing the lesser of two evils is a choice for evil.
I'm a Calvinist you insensitive clod!
I wonder how often the professor in the article though about going back into time to kill his father ...
> "Quantum behaviour is governed by probabilities. Before something has actually been observed,
> there are a number of possibilities regarding its state. But once its state has been measured those
> possibilities shrink to one - uncertainty is eliminated."
Which makes time travel effectively impossible.
Forget about filling your grandfather, just being there would be inconsistent with the theory because, according to it, if somebody observed the state without your future self in it, that state cannot be altered. And that "somebody" does not even have to be a person, it could be a cat, a bird, a fly or, possibly, even a germ.
Since the possibility of absolutely no observers is so improbable, the only practical way for you to travel back in time is if you already did it, meaning - somebody did observe a state with you in it.
So, there can be loops in time but they would have to be permanent.
Nah, Twelve Monkeys. Still one of the best Bruce Willis flicks, and the first Brad Pitt role that wasn't ghey.
"I assumed blithely that there were no elves out there in the darkness"
"The butterfly effect" was nicely made...
I question credibility of any scientist that brings it up.
If you want a *REALLY* good time travel movie that has zero action in it but still kicks ass then you should watch Primer. You may need to watch it a couple time to really understand what is going on. Their are those that are saying that you don't have to kill, you only have to (insert thing here). According to this theory, you wouldn't be able to do that thing -- time prevented it. Or it happens but that's the way it happened in your past and you didn't know it. For example, you delay your xxx-parents for a single second (becuase sperm is random). This isn't possible. Either something would stop it from happening or it did happen in your past, according to this theory. Two bits to think about.
"Do or do not. There is no try." -- Master Yoda (Half man, half muppet)
And seeing as absolutely anything in the past has consequences in the future (butterfly effect, etc.), then really, you would only be a tourist. Even the people seeing you there at all could have some effect, in your fancy 21st century clothes and whatnot. Also, you might kill some bacterii or a bug or something, which would exponentially effect the population of the future bug. How does this model circumvent that?
Commodore64_love: I don't comprehend people who're so frightened of death that they'll bankrupt themselves to stay alive
FTFA:
> 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.
How would you know?
If it was possible to change the past, it would also change the present. People will not "fade into the ether", it would be as if they never existed in the first place.
Nothing "obvious" there.
But we still remember the past. And, other than sleeping, historical experience is quite fluid and consistent. Unless our memories are erased upon alteration of the past, we would notice inconsistencies. At the very least, there would be gaps. You would be able to ask somebody "do you remember who the president was 30 years ago?" and nobody would remember. It would be noticable.
"I assumed blithely that there were no elves out there in the darkness"
Basically if I want to kill a person,
I would have to not know he is alive at current time plane.
Better yet, I know (even though it is not true) that he is dead at present time.
Maybe I could just get a caveman and tell him, "This guy(some1 annoying...president of RIAA for example.) in the picture is dead, but I want you to travel back in time to kill him."
If I try to kill the guy myself, it wouldn't work as I know he is alive today.
Intesting theory, I never knew the very fabric of space and time depends on the observation of humanity.
"Both popular and professional research articles in cosmology often use the term "Universe" when they really mean "observable universe". This is because unobservable physical phenomena are scientifically irrelevant; that is, they cannot affect any events that we can perceive, and therefore, it is argued, effectively do not exist. See also Causality (physics)." - Wikipedia
Time cops!
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.
Of course we would never know if this happens, since our memory would be changed instantly and we would have no recollection of ever having seen the person.
If you did manage to time travel back in time, did the universe you left still even exist?
Sure, the universe you left still would exist in your mind, but does it even exist in reality?
Well obviously if some mischievous time traveller had been messing with the past then our minds would have been changed along with everything else, nothing would suddenly 'fade out' you would simply believe everything was normal and that the memories in your head had always been there - which they had. Any sudden change wouldn't be noticeable because you instantly would have lived with that change for the whole of your life. In fact the change to the time line would be similar to pulling a string - as you make changes to your current time (the past) the repercussions filter trough to the future (where you came from) instantly, just like when you pull a string the other end moves instantly, so i guess they are theorising that if you were 'attached' to this string, travelling back in time would create a 'loop' that would stop you from pulling anything - imagine if you tie a string to your arm then get someone to walk it round a tree and pass it back to you, if you tug on it its going no-where. This string basically represents any change you can make to the time line (in fact it would be many, possibly an infinite number of strings), so in fact absolutely anything you do from breathing to even just being there - even attempting in any way to 'materialise' your time-ship would be a pull on this string of change. By that reasoning you can forget about your grandfather - time travel itself would be paradox and therefore absolutely impossible. Thinking about it this does make sense, since just about any small thing you changed in the past would have a big effect on the future you can bet your ass there are an insanely great number of things you can do that would prevent you from being born or from travelling back, not just killing your dad. Its hardly a stretch of the imagination to think that just the act of time travelling alone would be the paradox.
But then there's the slightly less Hollywood theory that time lines are on an infinite number of parallel universes and any change you make in the past will simply unfold in the separate universe isolated from your original universe. But that would mean you disappeared from your universe at the point of time travel and arrived in another. Wouldn't that break conservation of energy?
This comment does not represent the views or opinions of the user.
The Schrodinger equation is fully deterministic.
It does not contain any random numbers.
To say that quantum mechanics requires
probabilities is just wrong. It is only
our attempt to describe things classically
that forces us to such nonsense.
Mike
To send somthing back in time, you have to send, not just the matter, but the space the matter occupies, along with anything else in that space.
This would create a void in space that would appear as a "pinch" when viewed. Light would bend twards the pinch and then reflected at an angle away from the pinch on the other side and object on the far side of the pinch would appear upside down and backwards, like a pinhole camera.
When the space gets where it is going, it would create a "bubble" in space. This would not be visible at all, as light would be bent around the bubble. As viewed from the inside, you would just be inside a black ball.
Opening a "window" between the space from the future and the past would have to work like a two-way mirror. How to get the light to wrap around the bubble, and be visible from the inside?
If you could overcome the "unalignment" of the border between the past-space and the future-space(imagine trying to line up two pieces of graph paper that are not the same rule, one 1/4" and one 1/5") then crossing anything from the bubble into the past space would establish a quantam link between the idential particles in the same connected space.
What sympathetic quantum state would each particle receive? If the particles from the future, adopt the state of the past, whatever object they compose would fall apart, if not violently. If both try to equalize, then both would fall apart.
So, although you could send somthing back in time, it can't interact with the past, et all, not even as a "ghost".
Ignorance is amusing, stupidity is annoying.
And seeing as absolutely anything in the past has consequences in the future (butterfly effect, etc.), then really, you would only be a tourist. Even the people seeing you there at all could have some effect, in your fancy 21st century clothes and whatnot. Also, you might kill some bacterii or a bug or something, which would exponentially effect the population of the future bug/bacterii. How does this model circumvent that?
Commodore64_love: I don't comprehend people who're so frightened of death that they'll bankrupt themselves to stay alive
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.
Does anyone else read "researchers speculating" and see "researchers couldn't find a solution to the problem, so they guessed it must not be a problem at all in practice".
Wouldn't that only be true if you did something that effected you personally or people responsible for your ability to travel through time. If I went back in time and killed some nobody everyday citizen, I think it is very IMprobable it would effect me if they had no connections to me.
It would change the future possibly, but only as far as the people that person would have interacted with had the fellow not been killed.
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.
That's a HUGE assumption, and incredibly illogical! If those indiviuals births had been prevented, they would not be here for past events and hence, we would have no memory of them ever existing. So how would we ever notice if they had been erased?
According to Einstein, space-time can curve back on itself, theoretically allowing travellers to double back and meet younger versions of themselves.
I'm going to plead ignorance on this one, but isn't it impossible for two differnet bodies of matter to exist in the same precise location at exactly the same time. To be able to go back and meet yourself you have to be able to exist simultaneously as whatever may have been occupying that same spot in the past. Or am I missing something?
The researchers say these constraints exist because of the weird laws of quantum mechanics even though...
I don't think researchers in quantum mechanics would use adjectives like "weird" to describe the laws of their field of science, that term is more generally used by people who have little knowledge of a topic, like members of the mass press.
I always thought of this myself even without having read it before... it just seemed logical.
Imagine a quantum process is discovered that can be used to receive a signal from a point the future and put the result in a que. You create a computer with such a temporal quantum receiver that stores requested program,data and job que. At some point in the unspecified future, the job que with programs and data will be loaded on to a seperate processor that is sealed from the outside world. The job que is executed and the result transmitted back in time to the first computer temporal receiver que : Temporal Quantum Overclocking .
That if you went back and killed your grandfather, then you do not return to the future you left from but to a split off universe.
So you would exist but you would never have existed in that parallel universe.
So you can't change the past of your home universe but you could go back and fork off into a different one.
She was like chocolate when she drank... semi-sweet at first and then increasingly bitter.
...if anyone ever does discover how to travel back in time, they will be able to rest assure that no one from the future can travel back and kill them to keep time travel from being possible. a few years ago i actually discovered how to do it, so i immediately hypnotized myself to suppress the discovery until i was sure no one could abuse my discovery and travel back to kill me. i guess the trigger worked!
It takes just a moment and an action to destroy. It takes some time and thought to create.
Wow, going back in time and killing your own father or grandfather. I didn't see that card at the Hallmark store! PS I didn't see any pictures of this new model. Is she hot?
eh?
"UNIX is very simple, it just needs a genius to understand its simplicity." -Dennis Ritchie
> uncertainty is eliminated
... must be rolling in his grave
I see 57005 people
so basically what this article is stating is that I cannot change events that have already occured. Keeping in line with that speculation, if I attempt to back to spot X, I will fail to do so because I was never actually there(event did not take place). Thus prooving that time travel is impossible
Even though this is a compeling example to explain the issue of quantum probability and its relationship with time travel, I believe I may have something to add.
It isn't necessarily the fact of knowing that one's father is still alive that is conspiring against an attempt to kill him in the past, but an event in time that is not even included within the set of possibilities of event that may happen. In other words, there is certainly nothing working against your efforts to kill your father in the past (knowing that he is alive in the present), it just simply isn't an option.
Consider this example:
Let us assume that events in the present certainly cannot be changed from events in the past. If the current state of space time were to be assigned a value of R, then the set of all possible events that occured to produce a state of R would be included in the set of all possible events before R. Also, because a present state of R would be the exact same with other possible events throughout time, these events would be included in the set of all possible events that would bring spacetime to a state such as it is at this very moment, R. Therefore, if one were to travel back in time, he or she would only be presented with the set of possible events that will ultimately lead to the present state (the state of spacetime that was left), R, because, we have already assumed that events in the present CANNOT be changed from events in the past.
Of course, what I have said is nothing new, and is certainly what this research is all about. I just wanted to make sure that, as I understand it, there is nothing working against one's attempt to change the future via the past, it just isn't possible within the set of events that could actually take place if one were to travel in the past.
This story is a dup. The original will be published next week.
--
make install -not war
Go back in time and be able to observe, only... no ability to interact with anyone either... it should be kinda like ghosts
The theory doesn't imply the mechanism that prevents time travellers from interfering with the past. In fact, relativity specifically requires that, if you travel across the solar system, you will end up in a different "time" than you started in. If time travel beyond that implied by relativity is possible at all, it should still be perfectly possible to travel into the past far enough away from the local cone of experience and interfere with whatever you want, no "ghosts" necessary.
"I assumed blithely that there were no elves out there in the darkness"
we'll they are assuming causality as a given. Oddly enough that is not necessarily the case. Bells Theorem plainly states that localiity is... ah fuck it...
Until I can go back in time and not spend seven bucks on ep 1 it is a worthless pursuit.
Though I will note time travel is not only possible but probable, deal is you can only go forward
As far as I see it, there is no way you can ever "decide" to kill your grandfather and/or impregnate your elder relatives. Though we all like to think that we are constantly making decisions and thinking and whatnot, in reality they are all the side effects of some extremely complicated chemical reactions. We do not "decide" to make these things happen, they happen because the reaction continues to cascade (of course, it is modified by sensory input and whatnot, but not anything specifically under our control). These reactions (as are all other reactions), are goverened by quantum principals.
So according to this theory, if we were to go back in time, the quantum states that would result in a chemical reaction in your brain to make you "decide" to kill your grandfather would never happen. Likewise, if the Chronology Protection Conjecture were true, the quantum states that would make us "think" of the idea of a time machine would never happen.
Sounds kinda bleak to me, so don't believe it if you don't want to (but did you really "decide" not to believe me?)...
--- At my sig, unleash hell.
I question credibility of any scientist that brings them up.
So, I'm AC and nobody will read this. Anyway...
These time travel hypotheses always sound like complete bullshit to me. I imagine that people have a certain model of reality, and then they are extrapolating things that--while they do fit with the model--won't be true. The model is broken!
One guy speculated that all the potential decisions we could have made in a day are actually made in alternate realities. But if you believe people make decisions based on the weights of neurons in their brain (and ultimately on something much less abstract), then the decisions we make aren't really decisions. There could be no alternate realities like that. The real probabilities are on certain quantum levels... as far as we can tell...
And here, in an alternate reality, you can't do anything to modify yourself... uh huh... For these kinds of ideas to get past the editors in all the places I see them, time travel must be a popular pseudoscience.
My intuition says this is bullshit. And I can't be bothered to really explore it through literature. But if anyone has ideas, please reply.
To which year does the poster think he has traveled? This has been proposed many times before.
Why?
If it were possible to travel backward in time and alter history, it already would have been. WWII (and others) would not have happened as certainly some future time traveler would go back and make sure that all the BAD dictators would never be born and all BAD things that happened, never happen. I use the wars as a point of reference because they are universally known/recorded events and everyone can agree that mankind would have done much better had they never happened. ANYONE can agree that it would be a GOOD thing to go back in time and prevent those terrible events from ever happening.
So either time travel is not possible, as future travelers would have already gone back and prevented certain things from ever happening OR time travel is possible and the past can not be altered at all. One possibility is that the M-Theory comes into play and any attempt to alter time ejects the traveler into another "brane"..
Also see, http://en.wikipedia.org/wiki/M-theory
I am my own grand father!
I'm so surprised nobody's mentioned The Hichiker's Guide. This is exactly the way Ford explained things to Arthur just before they were able to flag down the Heart of Gold. "Its like a puzzle. Things can only fit one way" or something along those lines.
And I don't see why you people have such a hard time comprehending this. It doesn't mean that you would be invisible and imphysical, it just means that what has happened, will happen, because it already happened.
so my master plan of traveling back in time and giving myself winning lotto numbers wont work because ive already observed myself being broke as a joke?!?!
So it's the basic concept behind Schroedinger's cat that prevents it.
So I wonder how many people are going to kill themselves by locking their fathers into sealed boxes and irradiating the box.
This sig no verb.
Bunch of sifi crap. Put this with transporters,S ecurity.
space elevators, light-speed travel, ray guns, and I-will-collect-all-of-whats-owed-to-me-by-Social-
There is an exlusive look on the past. You can access the past but only in read only mode.
If enithin kan gow rong it whil. (Murfey)
Since when did the word "model" replace the words "plan", "theory" and "concept"? There's a difference of meaning between the three, and this Slashdot article refers to a theory.
I figure it must have originated from the visual marvel of 3D computer modeling.
Another /. article where the science has been dumbed down to the point where the average person can understand it, and all the substantive content has been removed.
So I can't kill my own granmpa? Well, DANG, I'll have to kill grandma then.
So... what they're saying is that the so called grandfather-paradox is invalid because if you could actually go and kill your own grandfather, by definition you wouldn't have been born, which contradicts the fact that you were born (you know you were, right?). Nice way of turning the question around, a kind of Columbus' egg too, I had never thought of that. The best part is that it makes a lot of sense...
:) Oh, I guess I've just proved that, for me, their theory works...
So if someone invents a time machine, I'm free to go and try killing my ancestors, and I won't be able to do it no matter how hard I try (something will always go wrong). If this is true, it obviously says that time doesn't exist and all things are interdependent (even the past is dependent of the future), which goes against our notion of "free-will".
Still, I wouldn't do the "try killing your ancestors" thing, I might find out that some of my female ancestors was cheating on her husband, which would make me the causer of his death
The conclusion is... I definitely need to get some sleep, see ya all tomorrow...
The AACS key is NOT 0xF606EEFD628B1CA427BEA93A9CA9773F
Time is a concept because you die! Tic...tic....and freakin tic! You can't go back in your concept of time! Whats in the past happened and is now forever gone. You can quantum this and quantum that until you go tripping on a formula collection by collective minds (read -> recognized math). The biggest evidence to what I just wrote is: "Seen your future relatives yet?" Gah! Now go invent something that prohibits the natural breakdown of telomere instead! http://www.telomere.net/
What this world is coming to - is for you and me to decide.
And don't play the lost numbers in lotto, either.
Perhaps a thought experiment could help to clarify. Say that you knew, for certain, that there was a patch of grass in your front yard that was there 2 days ago. If you could, theoretically, go back in time and pull it out, what the hell would prevent you from doing so? The grass isn't going to move so that it won't be there when you get there, and you'll know for certain that (A) it was there and (B) Nothing horrible is going to happen as a result of pulling out the grass that would make you spontaneously change your mind about pulling it.
So what unearthly force prevents you from pulling out the grass that you know for certain "exists" in your time? The only explanation I can think of would be that you somehow lose your memory in the process of time travel, or something... but even then, you could destroy the grass entirely by accident, and no mysterious force (aside from God, which seems to be aside from this argument) is going to stop you from having that accidental destructive event even in the case I have stated where you might lose your motive to commit an action.
A more logical assumption could be that actions in the past are "locked": you can do what you want in the past, but it won't effect the time stream that has already been locked into place by the "first" set of actions that took place in the stream. It's like working with a duplicate of reality.
-Vendal Thornheart
This goes on the assumption that time is a single threaded linear model working at a fixed speed.
If you go back in time, and kill your grandfather, then you are never created, therefore you can never go back and kill your grandfather.
If the "past" model is "protected", blah, blah, divine intervention, blah, blah, intelligent design, blah, blah, blah.
Someone mentioned something to the effect of "If I had a gun to shoot my grandfather, would it misfire?". Sure, maybe divine intervention made it misfire. Does that mean a knife, rock, stick, or whatever would still not work? Beliving in some greater plan that would protect the past would also believe that we have no possibility for changing the future.
I, for one, know positively that you can change the future. Don't ask, unless you want a really long response.
If time were a multi-threaded linear model, by going back in time and making a change, it would effectively branch the timeline. Your branch (that you came from) would remain unchanged, because it's already happened. A new timeline, caused by the difference in history, would now be new. You would never exist in the changed timeline.
Maybe neither time nor space are linear. Have you ever experienced precognition or deja vu? 90% of the people who say they have, may be nutjobs, but there are some people who can see things outside of our concept of space or time. That is, space would be "remove viewing", and time would be precognition (future) or deja vu (past).
Space and time are concepts that we live with, and have been reinforced in us since childhood, based on potentially flawed observations of our elders. Don't forget, these are the same elders that believed: we are the center of the universe; the world is flat (~1640); space travel is impossible (~1930); "Everything that can be invented has been invented" (1899); and we are alone in the universe.
We will find that we are completely wrong in many of these concepts, and in a few thousand years (assuming humanity survives) will be laughed at for some of them.
I'm not going to say by any stretch of the imagination that I should be right, but don't take any explanation as fact until you're very sure.
Serious? Seriousness is well above my pay grade.
"Oh my god! How did i miss?" "Alright that's it. I'm going to live in the cave. Church -Red Vs Blue
They can talk about quantum probabilities till they're blue in the face, but until they accept the fact that there are more measurable dimensions beyond time, we'll remain stuck in this stupid mindset that you can't travel back in time and kill your grandfather.
By this rationale, the very act of time travel will destroy you, because it will cause two copies of yourself to occupy the same three-dimensional space at the same time!
A better theory would be one that proposes "cause" as another dimension, where all objects have specific properties at a point of length, with, height, time, and cause.
Cause provides a kind of branching decision point, where one "reality" diverges from all the rest. By going back in time and killing your grandfather, you alter your "cause" from that point forward. If you travel forward in time, you'll find that the "you" that would exist through your father in that "cause" reality does not exist, but you can still exist since you travelled there from a forward point in the "cause" that created you.
Expand your mind.
...the Bill and Ted time theory.
Sounds obvious, but it does bring to mind the Terminator movies - I wonder if the technology SkyNet was created with didn't allow it to see this vital fact?
Beware!
http://xxx.lanl.gov/PS_cache/quant-ph/pdf/0506/05
jdb2
(from the post...):
Unless!, you take advantage of the time continuum heap exploit.
The real problem is not whether someone can or cannot create a paradox by traveling back in time. The real problem is that our understanding of what time is can't be correct. Unfortunately, we have no real clue as to what time really is. We have found only one proven way to influence time, e.g. by motion. And even that is relative to the observer. This means we all experience time differently, however small the difference. Another, as yet unproven, hypothesis is that by approaching a temperature of absolute zero, and dragging the fabric of spacetime around by using a very large gravitational field, time will begin to act like a physical dimension. So, until we can test what time is, any statement about whether we can or cannot create a paradox by traveling back in time (whatever that means) is premature.
The NSA: The only part of the US government that actually listens.
time travel is not possible because only pure light which is pure energy can travel at a speed which will stop time but not exceed time, and mass (particles) has way too much drag to even come close to the speed to travel the speed needed for time travel so it will never happen, and remain only a theory on paper...
Ok, this model solves the problem that I cannot kill my grandfather, but there is another problem: I am not yet married, not found a mate for my life. I am 24 and my father married with 32. So there can be possible that that guy that married my mother 25 years ago was me - This because I can go back in time now, meet my mother, marry with her, and have a son that will be me! This makes a kind of loop in time!
You can go back and kill your grandfather. However, the probability of all your constituents teleporting back in time that far is much smaller than the probability of your grandfather spontaneously resurructing or you being born out of goo.
Causality can be broken; it's just very improbable. The probability of sending a message to a faraway listener at faster than light is probably less than the probability of sending a message and random noise at the listener just by chance translating into the original message.
Of course, this is all guesswork.
Why, oh why must our slashdot science section only post links to badly written articles by journalists who don't have a clue about the actual science? Why do we not have a link to the actual paper? Ack! There is not even a link to a paper, not even a reference or a clue as to where it might be found in the article!
SIGSEGV caught, terminating
wait... not that kind of sig.
This statement just ruined 9/10 of the plot of every time travel movie/novel.
Unfortunately, whether something is "known" is not nailed down in the article, or even the reader is misled for simplicity sake.
If something is observed by anything or anyone, then it has happened. In the physics world, if a tree falls in the forest and nobody is around to see it, it still fell in the forest. Your perception of that is not special. It turns out that the uncertainty on anything we can perceive directly (regardless if we have perceived it) is negligible.
The thing about quantum scales of time and space is that there is the possibility of something being in multiple, substantially different, states if it has not interacted with anything else since its last interaction. When there is an interaction, the thing is in just one of the states that it could have been in. So at that point everything is well defined.
So to summarize: It doesn't matter if you see someone get killed; they are dead as dead can be. Don't get your hopes up, as it has already been registered in the "physical consciousness" of the universe. It does matter to an electron, however, if it has interacted with another particle.
Actually, philosophers have had the theories, but time-travel sci-fi is, like most sci-fi, just a futuristic take on one philosophical idea or another.
:p.
The "new" model is actually called the "B theory" of time and isn't new at all (although this scientific explanation of it is I guess). The B theory is that every instance in time exists somewhere and it is always "now" in that instance, so there is no real past, present or future. In the B theory if you were to go back in time you would merely fulfil the events that happen in that instance of time, always as the way they were intended.
So if you went back in an attempt to kill the parents of the bully who harassed you in school you would find out that your attempts failed, and that they didn't change your "present" at all. In fact, they would have helped created your present. A good example of this theory in effect is the sci-fi series "Andromeda", which follows the B theory of time in its time-travel episodes. A more well known example is the movie 12 Monkeys.
Star Trek on the other hand follows the multiple futures theory, whereby if you go back in time and change something you actually from that point on move down a different branch of time into an alternate future. The Butterfly Effect is another movie example of this.
The problem with the B theory of time is that it requires a deterministic universe, which is an unpleasant who isn't a materialist (ie. you believe you're made up of more than just matter). Of course the alternate timeline theory also has its own problems in that regard, wherein if you can exist in multiple timelines then which one is really you and where is your soul? If you're a materialist then no worries
My own theory on the matter is that time is nothing more than a human construct. Matter changes, and one change takes place before another, and we measure the order in which these changes occur and call that 'time'.
That they used a picture of the Tardis in the article. Long live Doctor Who!
Anyways, there was a whole episode on this kind of thing just recently, number eight of the new series. Apparently the Time Lords control those paradoxes, so there' nothing to discover. After all, we all know that everything in Doctor Who is real, right?
I am Whovian. Hear me *vworp!*
Interview on timetravel and paradox
I forget the name of the short story, but the female character ended up being her own great grand-daughter, as a result of a letter she received from her husband/great-grand-father.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
..I can still get first post!
How many Slashdotters would bother with reading it, do you think?
What's the word to describe this washed-down commercialization of science news that characterizes stories like these, the content of the Discovery Channel and TLC?
- Roey
ok, time is a dimension. if you go back in time and kill your father then go back to the future you will simply return to a future in which your father was killed.
:P (hey, no disrepect my uncertain homies!)
in fact, once you go into the past you change the state of that universe (since there are many) and can never return to the state of the universe from which you left.
I abide by this simple thought concerning paradoxes: if someone is ever going to create a machine to go back in time and create a paradox which destroys the universe then they already would have.
The universe is here so obviously there is no worry about universe-destroying paradoxes.
However, thinking that the laws of physics would be able to keep you, after traveling back in time!, from putting a bullet in dear old dad...that just seems ridiculous to me.
anyhow, not a physicist - but then again, what are quantum pysicists doing speculating about time? they can't even get gravity (a proven time warper) straight!
This theory just ruined 9/10th of the plot of every time travel movie/novel.
I think many of us are happy to say... NO SHIT!
Time fits together kinda like a jigsaw puzzle, anything that you go back in time to do has already happened. ...or something like that.
I wish I had the exact quote.
When are we going to stop with the time travel crap? It's impossible. It has been debunked a million times with pure, simple logic. Yet, people keep dragging it back up.
You will never be able to make it big on the stock market or get that hot chick by screwing around in the past! Enough already!
I'M MY OWN GRAMPA -
Homer & Jethro 1956 RCA Victor 6765
Many, many years ago when I was 23
I was married to a Wider who was purty as can be
This Wider had a grown-up daughter who had hair of red
My father fell in love with her and soon they two were wed
This made my dad my son-in-law and changed my very life
For my daughter was my mother cause she was my father's wife
To complicate the matter even though it brought me joy
I soon became the father of a bouncing baby boy
I'm my own grampa,
I'm my own grampa
It sounds funny I know
But it really is so
I'm my own grampa
My little baby then became a brother-in-law to dad
And so became my uncle though it made me very sad
For if he was my uncle then that also made him brother
Of the Wider's grown up daughter who of course was my step-mother
My father's wife then had a son who kept them on the run
And he became my granchild for he was my daughters son
My wife is now my mother's mother and it makes me blue
Because although she is my wife she's my grandmother too
I'm my own grampa,
I'm my own grampa
It sounds funny I know
But it really is so
I'm my own grampa
Oh if my wife is my grandmother then I'm her grandchild
And every time I think of it, it nearly drives me wild
For now I have become strangest case you ever saw
As husband of my own grandmother I'm my own grampa
I'm my own grampa,
I'm my own grampa
It sounds funny I know
But it really is so
I'm my own grampa
-fb Everything not expressly forbidden is now mandatory.
Time travel would only be possible to a receiver.
That is, you would have to 'mark' a location in time/space by activating your equipment there to make one end appear, then wait for a while to open up the other end. Which would appear at the receiving end to happen instantly
Then you might be able to send single photons or such through, possibly a data stream.
In todays world, Data is very very valuable.
Food/Mates used to be the most valuable thing (Hunter/Gather)
Then means of producing food, and protecting your mates(Farming/Towns)
Then things you could trade for a place in a town or farm grown food (Gold/Silver)
Then things that represented those things (cheap coins/paper money)
Then data that represented those things (electronic currency, loans)
Now data that represents the value of those things (Currency Exchange Rates, Stock Prices, Commodity Futures) might be the most valuable.
It may be surpassed by the systems and methods used to track and manipulate those data values; an accurate method to predict the future value of a commodity would be much more valuable than a few data points on it's graph.
Mathmatical formula's are bought and sold based on their ability to process data, it's called Software.
The source code to Linux 3.0 Kernal, or all the gold in fort knox?
The parent post was moderate +5 informative, but now as I enter a reply all the mod points have ceased to exist! Interesting phenomenon.
Quantum behaviour is governed by probabilities. Before something has actually been observed, there are a number of possibilities regarding its state. But once its state has been measured those possibilities shrink to one - uncertainty is eliminated.
... :)
So basically, anything's possible -- unless it's impossible. And the Nobel goes to
Cheers,
IT
Power corrupts. PowerPoint corrupts absolutely.
I've always hated these theories that say time is one line, and everything must fit into everything without paradoxes. Things don't have to make sense. Anyway, I don't think that things work like TFA suggests. In my opinion, time travel is impossible. To me time is nothing. You can't change anything about time. However, I believe that there are infinite universes, with infinite variations, and to achieve time travel, you would travel to a similar universe that was at a different period in time. It would have the same effect as traveling in time, but interfering with things like killing your grandfather would not affect you.
Unfortunately my brain isn't working quite right today, so forgive me if that sounds stupid or doesn't make sense. I have explained my theory much more clearly in the past (no pun intended).
No existe.
In theory, you could go back in time and meet your infant father but you could not kill him.
:-)
What would the stoppage look like if you tried? Would Phil Jackson appear in a robe shaking his finger at you?
The theory is cleaner if it forks off a new time/universe branch. It is like copy-and-paste programming. Screw factoring, eh?
Table-ized A.I.
"Young men, hear an old man to whom old men hearkened when he was young. -- Augustus Caesar"
Nibblonian 1: It's a genetic abnormality which resulted when you went back in time and performed certain actions which made you your own grandfather.
Fry: I did do the nasty in the pasty!
Nibblonian 2: Verily. And that past nastification is what shields you from the brains. You are the last hope of the universe.
The war with islam is a war on the beast
The war on terror is a war for peace
Actually, you see, time travel is really easy, but it will never be invented (more accurately you will never KNOW if it was invented).
If one were to invent time travel, eventually others would find out. The practice would spread over time. People would travel back in time and forward, changing the timeline back and forth and spreading the possibility of time travel to others.
One small change and whoops, there goes my worst enimy's family line (or maybe my best friend's, who can tell?)
If you could teleport anywhere instantly, what is the meaning of distance? how do you figure something like velocity=distance/time? Distance no longer becomes a measure.
In the same way, with time travel we will go through every possible timeline in no time at all--instantly. Time itself is no longer a possible measure of duration.
To examine the timelines would be impossible, thrown at random, being modified and every modification brings a hundred more.
The only thing that could possibly stop the timeline from fluttering about is if some strange set of changes stopped time travel from being invented in any iteration of the timeline, once that happened, BANG the time line is fixed and will not change again.
That's our timeline.
and fuck yourself. Enough of this twisted grandpa shit. Suck your own dick! Eat your own pussy! 69 yourself! Once two of you are back in time, those two could go back in time for a threesome. Repeat for vast time orgies with yourself. What male hasn't tried to give himself a blow job? Make it a reality.
Well im glad we figured that out...does that change the fact that we still cannot travel back in time?
You've also observed that your father doesn't remember you from 50 years ago, therefore you cannot even meet your father 50 years ago. In fact, all you can do when you time travel is make no difference at all, since nobody is allowed to remember you.
No, the better model of time travel is the many branches interpretation: The only way you can time travel is to create a universe like the one 50 years ago but modified to include you.
paradox issues aside, if you travel back in time the earth won't be at the spot where you 'reappear'.
I wonder if they've thought this through.Effectively they are saying that the present dictates the possible past that a person may travel to.
Remember the bit in Big Brother where they state: "Who controls the past controls the future: who controls the present controls the past"
It's an endless loop - a deterministic past leads, inevitably, towards a deterministic future. If both of those are a given, then time travel is most definitely possible since such travel has been predetermined. And while it might feel all spontaneous and new, there is no action that is not predetermined.
In fact, if the future is predetermined, the last moment in time may be the important one, not the first, since it's the state of the universe in the last moment of time that determines the state of the universe in all preceeding time.
Or not. All I can say is "Fear of Quatum Mechanics profits a man nothing!"
Concrete analysis...
Some people have been saying that this article wasn't very clear on the subject etc but I think it conveys the point well (assuming I understood it correctly).
:P
Basically, there is one true constant that says "Hey, this happened. This is the way it is." When you go back in time and tried to kill your grandfather *something* would stop you. What stops you is not defined. But we know you were stopped because in the end you were alive. So what really happened is that when your grandfather was in his own time minding his own business, you were actually there but you didn't kill him.
Some time travel lore likes to describe events happening a number of times (I'll explain). For instance, the "first time" your grandfather was getting your grandmother pregnant was the original time, the time you weren't there trying to kill him. The second time it happened is when you go back and watch him doing your grandma but are so sicked out that you hurl and bail out and go back to your own time. But really, this new theory is saying that there was not first, second, etc time at all. Just once. During the "first time" you were actually there so the first and the second time co-exist.
I need to just step away from the keyboard
"...if people respected copyright more, like you guys do with the GPL so religiously, [the DMCA] wouldn't be necessary."
So now we could potentially have someone come from the future and confirm our destiny for us.
Probably, for some reason, they couldn't tell us specifics but they could "push" us in the right direction.
...and I have a physics degree from UC Berkeley.
One of the greatest errors in science is the over-extrapolation of low-level models/theories, traversing many levels of scale, completely disregarding the assumptions and implicit models of the initial context. It's just foolish. It makes otherwise respectable people (and theories) look like total asses (or utter shit), and I don't know why real scientists put up with it.
To maintain their funding, perhaps?
That being said - I haven't looked deeply into yet, so who knows?
Dammit! I am employed by Paramount in the year 2154. The newly enacted Truth In Television Act in combination with this time travel model is going to force refilming of 95% of all Star Trek episodes in our archive (all series are impacted).
I traveled back in time to try and prevent this story from being posted on Slashdot so the discovery would stay unknown. I thought I made a big enough BackJump(tm) but for some reason I couldn't quite manage to stop the post.
Now the best I can do is hope to prevent the same story from being reposted in three days... another futile task...
My model also solves the Grandfather Paradox.
It's called "time travel doesn't exist".
Here's a solution:
Past = Read only
Future = Write only
Present = Read/Write (infinitesimally small overlap between past and future)
From TFA: 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.
"Fading into the ether" seems to be based Back to the Future. Is that model of reality correct? If something was to occur in the timeline and prevent someone from being born, why would they suddenly fade away? Would they ever have existed in the first place? If they were never born we would have no memory of them...
DOH! guess I'm arguing myself into a paradox. I prefer The Butterfly Effect.
I've thought this since I heard about the concept of time travel. Of course, whatever you have done, in the past, will always be repeated by yourself when you go back from the future.
If you cannot alter anything that would change the present then you cannot go back at all. because even your footsteps would change the placement of dirt in the present.
But if time travelers are like ghosts, how's Rufus going to travel back in time to help Bill and Ted pass high school? Booogus!
I don't see how this is news, or if it actually is news, in a very mathematical theoric way, the BBC article doesn't explain that at all, further what I could write after watching three Back To The Future movies...
1. http://www.iep.utm.edu/t/timetravel.htm
2. http://plato.stanford.edu/entries/time-travel-phys /
3. http://philsci-archive.pitt.edu/archive/00001673/0 1/TMArchive.pdf
Not an especially accurate headline. Someone might actually have come up with a "new model" -- not that TFA actually says anything worthwhile about it. But the idea itself isn't new at all. See, for example, Cliff Pickover's Time: A Traveler's Guide for some light (but enlightening) material on Closed Timelike Curves. Basically TFA is saying that they think that CTCs are the only kind of time travel that could exist in reality, and apparently that they have some sort of "model" that proves this, but doesn't actually provide any sort of explanation of the model; it's just sort of a fuzzy explanation of CTCs.
sad, sad news! If you can't change the past or the future why bother travelling in time at all? It is just like going to a museum - see but no touch...
Yes, I did not read TFA
If we arbitrarly set time as a 4th dimension, which encompasses some arbitrary number of 3 dimensional states, space, then can't probability be a 5th dimension that contains all the different possible timelines?
We unintentionally move forward through the 4th dimension of time right now. Let's say we can move through time freely with a time machine, but by doing so there is an unintentional movement 5th dimensionally through possibility.
We see no time travelers because in our timeline the time machine is never created, but we might eventually create one, but every time we go back in time with it, we travel unintentionally through probability and there's probably already a bunch of time travellers there, we can't ever go back to our own original histories.
... so there's no chance of stopping Lucas from making Episodes I-III?
Let the commencement BEGINULATE!
-H. Simpson
Supervising Technician (Safety)
Springfield Nuclear Power Generating Facility
Springfield, KY
"Well, good luck finding a judge that doesn't run a bestiality site."
Wanna play some poker sometime?
yeah, how could anyone face himself from the^He f^[[3~future^H^Hre
IWASSAHERE^H^H^H^H^H^H^H^H^H^HIWAS^H
...I repeat, we have normality. Anything you still can't cope with is therefore your own problem.
;P I'm such a kidder.
Oh sorry, that should have been:
"Quantum behaviour is governed by probabilities. Before something has actually been observed, there are a number of possibilities regarding its state. But once its state has been measured those possibilities shrink to one - uncertainty is eliminated." -- the "normality bit"
-"...bad old ideas look confusingly fresh when they are packaged as technology" - Jaron Lanier (Digital Maoism on Edge.o
Time travel is so in depth that many people believe it will never get out of the sci-fi area into regular science. Many cultures in the past have viewed time as a line, starting somewhere, and ending somewhere else, without squiggles, or sidetracks etc. Others saw time as a circle where it could seem that you come to the same spot over and over again, or the circle could be infinitly large and the traveler would just arrive at spots that seem familiar to a past time.
When looking at a topic such as time travel you invariably will choose one of these views and practically everyone thinks linearly (it's more prevalent in modern cultures, and makes more sense for time travel). There is no evidence behind an understanding of time however, it's like the theory of relativity. A linear view of time works fine, so does a circular view. Relativity works, but without a foundation in other scientific laws, there is no reason to say that relativity is uniquely true.
When theorizing about complex ideas like paradox's and time travel behavior it's almost impossible to come up with a good understanding without knowing the foundation of time. I must say I agree with you on the binary interpretation of time travel. I wouldn't be surprised at all if paradox's become one of the old legends when (if) us humans come to a real understanding of time.
"And we have seen and do testify that the Father sent the Son to be the Savior of the World"
1 John 4:14
This is hardly a "new" theory. At best it is a restatement of the decades old theories that are expressed here:http://plato.stanford.edu/entries/time-travel -phys/
Non sequitur: Your facts are uncoordinated.
If you went back in time and killed the baby John Shumacher, it's not like President Shumacher would have disappeared in the middle of today's ceremony celebrating the 10th anniversary of peace between Israel and Palestine, or last week when he renewed his vows with his husband. It would simply be as if some baby had died 50 years ago and so nobody would have any thought or memory of him as a politician.
If I go back and kill my grandfather I will not be born. I then could not go back to kill my grandfather so I will be born after all......... The only way to get out of this loop is the theory about creating alternate realities. I kill my grandfather wich will spur a new reality in wich I will never be born, it will however not change my reality because of the loop.
Quoting TFA:
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.
No wonder they're having so much trouble filming the movie version of "A Sound of Thunder." I was so looking forward to see it.
Tag lost or not installed.
I get tired of people being so limited in their thinking. A quantum wave function does not need to collapse. It can vibrate between all possible futures. When we observe it, it is our interaction with it at whatever point it is in its vibration that changes what universe we are in. The wave appears to collapse as we have now changed our own location in the multiverse relative to the quantum wave we were observing. Notice that we ourselves can act like quantum waves and that we like the wave we were observing are vibrating between possible realities. We simply made an observation or in other words we engaged in action that caused a quantum level interaction that pushed us away from another quantum waves location givings us the appearance of its collapse into one certain reality. As to what happens when you kill your grandfather in the past. In the universe you leave you would appear to vanish forever having engaged in a action that moved that reality away from you. In the past you do kill the man whose particles participate in the multiversal wave that your Grandfather participates in. The result is that you have now moved yourself into a universe in which the matter making up your dad's structure is dead. You still exist because you came from the future at a point in a another universe in which he still exists in the living form of your to sire you. So, ironically, the answer is that you cannot kill your actual father but you can go back and kill a version of your father and in so doing remove yourself forever from the universe in which your father exists. :-)
I say if time travel is possible, you should certainly be able to kill your grandfather as well as the rest of the human race if you like. Remember that we live in a multiverse of many, many possibilities. Going back in time and killing everybody doesn't mean those people that you left are going to disappear forever. The problem is that they will disappear as far as you're concerned. By going back in time and killing your grandfather, you've tied yourself to a different set of probabilities than the one you left.
You can think of it like navigating a huge binary tree of 50/50 probabilities. After navigating back far enough in time, performing an action, such as killing your grandfather causes you to force a choice on existence, but existence from your perspective.
We can see from this that navigating back and forth through time is not a linear activity at all, but a multidimensional spatial problem. We think of moving forward in time as 'freezing' and then 'arriving' within our own probability stream. I believe it makes more sence that if you are able to navigate backwards along a probability tree, that you should be able to navigate along a series of possibilities to arrive at whichever one you desired most.
All-in all, I'll bet you can kill your own grandfather.
Assumption: Time exists.
Deduced: Paradoxes.
Conclusion: Time does not exist.
Time in the way we conceive it may be an incomplete model of reality.
For instance, we accept that light speed is the maximum yet we think the universe is expanding faster than light. This is treated as though a central time has been running at a constant pace while space expands - but what if it is time itself that is speeding up so that everything is going to its future state earlier? Locally, clocks would run at the same rate, but they would be actually falling behind the universe's time.
It's not implausible since clocks don't have to run at the same pace everywhere, as shown by relativity. Indeed there may even be more than one "clock" experienced by any single point - we can have a local "clock", and the universe can have a central "clock".
Destruction is fairly easy as entropy runs its course but energy and materials can be used to create some order and in some cases restore, or at the very least, replicate past states. Thus we can conceivably build worlds that existed before. Thus a clock can make a quantum leap backwards.
A resurrected world would find itself embedded in a place where many resources have been spent to build it though. If resources still exist, as entropy unbuilds the world, it may seek to rebuild.
Everything we see is history. Light took time to travel to us. If we can determine our past from light that bounced off us and then off something far away and came back, or was bent around a black hole and came back, we could construct a past situation and interact with it. Though the inhabitants of the situation would be told what year they are supposed to be in, they would be in two different times.
So if we look to our past would we see history as told or an artificial constructive process?
Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
This is assuming humans are really ultra important in the grand scheme of things, especially versus other more physical interactions that WOULD get impacted if someone were to travel back in time. And if the theory is saying only human interactions won't get impacted OR that no physical interactions get impacted at all - that is a hard pill to swallow.
I would like to see an explanation for why someone's actions, were they to travel back in time, would have a net effect of Zero on the physical world around them?
Take out the probabity of your relations. What about the impact of simply walking somewhere? Do those footprints not exist? Think that's not important detail. Tell that to scientist's who have found dinosaur prints millions of years old. It certainly impacted their life.
Ah, but you see, if your prints had a probability of 1 to be found by that person, they would be found anyway. Or so I guess.
And those probabilities calculations can be thrown out the window because everything is then predetermined anyway. Unless when we travel back in time we are ghosts that don't walk around and may accidently step on a bug or two.
motherfucker - Not cursing, just setting time-continuum disruption experiments.
;)
And what was that I heard about a warm-hole?
You can't handle the truth.
Then does that mean going forward, there is such a thing as destiny?
-R
If you were to go back in time, there are one of two logical possibilities, depending on which theory you believe:
Either you CAN alter things or you can't. There's NO IN BETWEEN!
So, if the case is such that you *can't* alter things, then you're an observer. Simple. You can't change anything, including the position of a blade of grass in the wind. The world is essentially made out of unmoveable "stone" to you, including air molecules. There is no "a car would suddenly come out of nowhere to mow you down" to preserve some incidental fact such as that your mom needs to live to give birth to you. It's equally as impossible for *anything* to be altered in even the slightest way.
Now, the other possibility is that you *can* alter things. In this case, as soon as you appear in the past, air molecules have been displaced around you, and as a result you've created an altered branch of time/reality. If this is considered allowable (remember, you're already on another track), then there's literally nothing that *time* is going to do to stop you from killing your mother. Since this results in a serious paradox, I vote for the first theory as the only logical possibility (assuming one can travel back in time at all).
I've never quite understood why it is that there has to be a stable state in these "paradox" arguments. Looking at other physical systems, when you close a feedback loop in such a way that it is unstable, then the system inside the loop will oscillate.
It happens for mechanical systems, it happens for electrical systems (in fact I know it is trivially easy to make it happen in electrical systems - it is the source of many an engineer's headaches). Period of oscillation is related to the phase delay through and time constant of the loop.
Is there an known reason why this can't happen in such a time travel loop? (other than it would seem unnatural - although no more than time travel itself).
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. - it's not 'Clearly' at all. How the hell would anyone notice that people suddenly fade into ethr if simply put all of the events that were supposed to happen after death of someone, who was say killed by a time-traveler in the time-traveler's past would not happen in the future of that past?
This is so stupid, I can't believe it's printed.
Then again, GB is constantly printed too.
You can't handle the truth.
Sorry if this has been discussed before, but I don't have the time nor will to look thru all the posts right now.
Anyway, to get back on topic, if we can't change the past, then you can assume that it was meant to happen that way, which means that we have no free will towards our actions in the present, right? What we think as choices and free will has already been determined by our destiny.
So what happens now?
rule of paradoxes: they don't exist.
2nd rule: see rule #1
Science : Proprietary , Knowledge : Open Source
Even if you have a look around you are changing the future because of the extra sensory data you take back with you. The extra data will influence your thoughts and thoughts influence your actions. Does the theory assume that you come back to the present you left behind?
self centered model to me. First rule to remember is that time is relative. If you goto your past that past is now your present. Past, present and future are nothing but words to describe one's point of view of time. Which I like to call "Temporal Relativity". Now that we got that out of the way.
If you where to go back in time and your time pod lands on your grand father he would be dead. Now you ask how are you born. Simple, parallel universes.
Let's start over, it's 2005 and you never traveled through time yet. In your 1950 your future self never traveled to the past. That is set and can't be changed. Now you get in a time pod and travel to 1950. By making that choice you simply made a new future for your self even though you're in 1950. Simply put, you traveled to a parallel universe where you did travel to 1950.
Now by accidently killing your grandfather in that universe all you've done is prevent your double from being born. If you where to travel to the 2005 you would exist in a 2005 where you don't exist.
For every possible choice exist a universe where you made that choice.
If you counter in parallel universe's with time travel you can remove the grand father paradox.
Only humanity would be so arrogant to believe we can screw up the universe with such an idea as the grand father paradox.
We, existing in this universe, are on a crash course toward the future.
There's no stopping it or slowing down of time, in the traditional sense. However, it might be possible (with the help of absolute zero) to stop all things in the area of the absolute zero. This would be akin to stopping time, as nothing could be happening within that area.
Unbaking a cake or uncracking an egg is a good example of going back in time. Hey, if you can take a fully-baked cake, reverse the steps, and make it back into cake-mix-egg-and-milk-inna-bowl, that's good enough time travel for me.
Job? I don't have time to get a job! Who will sit around and bitch about being broke and unemployed then?
Time goes in one direction, for those experiencing it. For you, if you were to go back to before you were born, and kill your father - there is no paradox. You'd still exist. You're father would be dead. You're father wouldn't have a child. But you would still remember growing up, and all the things that happened in your life. If you then went "back to where you started", your father would still be alive. However, if you went back to the same year/month/day/hour, etc., but not the same place, then your father would be dead, and no one would know who you are. But you would still exist, and remember all of the events that happened to you. The continuum DOES NOT change. There is no paradox. There is no way to make a paradox.
What happens if I go back and screw my mother and father myself? Can I? Can't I?
I really doubt that any scientist who disproves the theory by going into the past to disrupt their own conception will publish their findings.
Of course, if they do publish, will anyone be able to replicate their findings?
Doesn't this ignore that quantum theory is generally applicable only at a subatomic scale? This new theory seems a lot like trying to calculate a function on a value outside its domain.
Let's worry about making time travel possible before wasting precious time on this type of worthless bullshit. If there's no possible way for you to afford a Lamborghini, why waste time worrying about what the colour it will be?
Jeez, some people have entirely too much time on their hands.
If you actually managed to become your own father or grandfather you would be creating a genetic loopback that would only end with death or a level of genetic mutation where you can no longer procreate (assuming you don't look horrible enough to just drive your ancestors away). Thats also assuming that the mutation doesn't change your lifestyle enough to where you never travelled back in time in the first place. In almost all events you would break the cycle though and time would snap back to its present form.
I prefer to resolve the grandfather paradox in this way.
Using this paradox as the model:
1. You go back in time.
2. You shoot your grandfather.
3. You didn't have a reason to go back in time.
4. Your grandfather doesn't get shot.
5. Repeat steps 1 through 5.
Assuming that the universe is made marginally different
from the time travel, a number of possibilities arise,
but there is only ever one observable result.
1. Your grandfather died from some natural but
otherwise highly unlikely event before you were born.
2. Your time-travel machine fails.
3. You successfully travel there, but fail to kill him.
4. While you successfully kill your grandfather, your
grandmother remarried.
In fact action at a distance has been apparently demonstrated. Strange, but what I find beautiful is that while the particles are linked instantaneously regardless of the speed of light, the QM nature of the problem, prevents communicating backwards in time or violating causality with this. I regard that as a nice confirmation of the Novikov Self-Consistency princinple.
Here's the vastly oversimplified version of how this works. You have two particles whose characteristics are linked, say photons in a singlet state. You measure the x axis spin of one, and the y axis spin of the other. Since each is undefined when the other is known according to QM, you either have violated QM, or else measuring one has to instantaneously (as in faster than the speed of light) change the position of the other.
Well, it appears that it's the latter- measuring particle A makes particle B change its values, and faster than the speed of light.
Best part: You get action at a distance, but no possible communication back in time, because measuring A makes the complementary values of B 100% unknown, so while there is action at a distance, you can't use it to send messages back in time.
I remember when I was visited by my future self. I gave myself some investing tips and reminded myself that in the future I must go back in time to provide those investing tips, even if I am rich.
To me, time travel reeks of paradox or getting something for nothing, or both. I faintly hope that I can eventually describe that paradox.
Dust... Wind... Dude...
Assembly is the reverse of disassembly.
If you go back in history kill your grandfather and prevent yourself from being born, then you would not be able to have gone back and kill you grandfather...
There isn't much like the scent of a fresh harddisk
I've been telling people that this is the way things are for years, but I ain't wrote no paper about it. Some one did make a movie that depicted time travel in this way -- The Army of the 12 Monkeys. A realy good movie in which a guy who was sent back to avert a world wide man made plague outbreak ends up playing a small part in insiring the guy who did it and in leaving the evidence that the future (his time) people used to deduce that they knew who caused the events and could stop them.
This doesn't make any sense. Every atom has some effect on its neighboring atoms and so on, so any presence of a body from the future would be a disruption, even if not as noteable of a disruption as it would be to kill your own mother. The probability of every thing that has already happened is permanently affixed at one, so all backwards timetravel is impossible. And for another thing, uncertainty is not the same thing as reality. Uncertainty means we don't KNOW how things are so we use probability to measure them, because its more accurate to admit our ignorance thus. But if a treee falls in a forest and no one hears it, it still makes a sound man. Even if there was no observer, every event would still take place and still be entirely unprobabilistic once it has entered the past.
In Soviet Russia YOU become your own Grandfather! ...No, that can't be right. Um, your grandfather becomes YOU! Um... Uh... You become your Grandfathers grandson?
Dammit, I hate time travel!
You need a FREE iPod Nano
Am I the only one whose first reaction to this headline was "whoa, now that's an impressive entry in the Miss America talent competition"?
So the best example of time travels effects we can come up with is a scenario in which we kill our own father?
My spidey senses are tingling..
Does anyone else get the feeling this researcher should be talking with a professional about dealing with some "present" emotional problems rather than timetravel?
why cant we just accept that there is a multiverse and 81 trillion copies of the universe with different combinations, like sliders, but perhaps 99% of these are very very close to each other with little differences.
At the local level - like which human marries which human and which on elives might be totally different in many multiverses, but the big picture of stars/galaxies, they most likely all are all there exactly the same in 99.99% of all multiverses....
So go back in time, change it, kill all the popes or all important people and the future is different, but its your future, but the orignal past of that future is still the same, because its just the same atoms aranged in different ways. From the atoms point of view time travel is no big deal, things change, who cares... but from ours POV yeah, heaps can change. But supernova still will happen - we cant "STOP" those.
All paradoxes die once you accept that when each time you go back in time, you traverse a different "TREE" of the 4th dimmension so that when you go forward you never go back to your original branch - but a different one.
THe concept of multiverse isnt too bad, its just the same atoms aranged in different 'location spaces' ie. same time different space. Each time you go back - you 'fork()' a new clone of the universe or a new branch that is unique to your timeline, or from the point you entered. Which overall for the whole universe might still be 99.999999% the same as the one you left, except what you change can be uniquely different for you, but not ever end up the same as the place where you came from.Just different patterns of traffic on the roads causing different people to live or die can have massive outcomes for the whole humanity down the 'road'.
Butterfly effect.
Multiverse, thats the secret to explaining all paradoxes.
Liberty freedom are no1, not dicks in suits.
There's one book by Terry Pratchett that has a nice explanation for this phenomenon, called the "Trousers of Time". ;o)
It states that time travel works like travelling in a pair of trousers. You start at the end of one leg (the present) and then, when you go back in time, you go upwards. If you then, at the top, kill your father and get back to the present, you don't end up in the leg you came from but in the other one.
It's all about parallel and branching universes but it's a nice way to explain it
charon
If somebody goes back in time, they're randomly thrusted to ' |time deviated from present|* C '.
Even if somebody goes back 20 years to kill theoretical parent, they are put somewhere in a sphere 20 light years away from present place.
The only problem is energy consumption and unbalancing energy costs....
Unless of course you sleep with your mother.
... being one's own father is not going to be nearly as messy as being one's own mother?
They cannot know this. A better way to put this would be to say there is no observable way for you to go back in time and kill your grandfather. IE if you do it you don't exist to observe it... or anyone else for that matter. Time travel antics are by their nature unobservable. For all we know they happen all the time and we are constantly in a state of flux as the realities of our history change from moment to moment by changing events of the past. The fact that we percieve the past as a continuous unchanging memory is not evidence that alteration of the timeline does not occur. IE we would not remember a former timeline because there would be no other timeline to remember. What happend happend and that goes for any changes as well.
Some are able to grasp that but then they think that if they were the traveler they would be aware of the changes and yet this is not so either given a single world line concept (no multiple demnsions for every possible scenario of existence). IE your memory would be in constant flux as you made the changes. So in the Back to the Future example Marty would never have gone back to the wrong house in BTF II as he would have known what happend because it happend to him.
So in the end time travel breaks down into two arguemnts. The first is always "Is it possible?" The second then becomes a question of the chicken or the egg.
Can you time travel ? No, end of discussion
Yes, Can you interact with your environment ?
No, Time travel isn't possible
Yes, parradox and how do you deal with the chicken and the egg.
if you can't interact (kill your grandfather) you can't do anything cause any interactino would alter the course of events. The parradox of killing an ancestor is simply an easy to grasp alteration but there are any number of other affects a visit to the past could have that did not cause a paradox for you but did cause a paradox for someone completely unrelated to you. The argument of the existence of such a parradox is summed up by the whole "if a tree falls unobserved in the woods does it make a noise" nonsense.
In otherwords the grandfather paradox, along with that damned tree falling are logical equivalents of divide by zero. It is something you can attempt to do but the system or manipulation/discussion cannot account for it. It is approaching but never reaching 1 or 0.
I don't ask you to be me. I only ask you not expect me to be you.
...and the past is a read-only backup!
I don't actually believe this, but:
A lot of arguments against the ability to change the past bring up the fact that people don't simply vanish. However, there are thousands of missing persons in the U.S. alone. We attribute these cases to crime or insanity, but what if...
I could use a good episode of Unsolved Mysteries.
Though the parent is intended as a joke, based on my own thoughts from reading the works of Einstein I believe it to be more insightful than the article and most of the posts here that fail to understand wny time travel is romantic BS.
There really is no such thing as time, only the relative differences in the states of energy of systems, where energy is observed as velocity (integration of acceleration as time goes to zero) or relative positions in an arbitrary coordinate system.
To go back in time is to rewind the state of the universe, effectively to reverse the vector of all energy (and fields). You can create a perspective that can change the relative state of a simple system, but this function will not magically rewind the states of arbitrary systems, let alone the gestalt.
Any equation that involves time is actually measuring some other assumed relationship. Time was linear in Newtonian physics because it only solves for simple systems with a constant field, but there's a reason that better theories involve an integration with time going to zero.
I cringe when I read Hawking and he jabbers endlessly about not understanding why time seems to have a vector and then ponders the magic of some wonder field that reverses it all. It's clear that he read Einstein and he could do the math but he missed the big point entirely; time is a big zero, always now, but energy has a vector and the universe is a directed rotor that cannot be simply deconvolved.
ps Thanks for the universe, God, it's mostly working pretty well thought I have a few suggestions.
Rather than assuming all possible history cycles exist simultaneously and collapse as we watch them, I simply apply a bit of Heisenberg's and a bit of Quantum Probabilities to come up with an (unorthodox) hybrid. Every time someone goes back in time, there's a Normal (Gaussian) distribution to the time they end up at. Consequently, "strange loops" (to borrow a term from Hofstadter) occur as they would with fixed travel, where you go back, kill your father, therefore don't go back, therefore are born as usual, therefore go back in time to kill your father, etc. The only difference is you'll hit times farther forward and back from the target time, until one time, just by chance, you'll end up too FAR forward or back to execute your nefarious patricidal plans, thus exiting the loop.
The observed effect would be that of a single stable history, where it feels impossible to disrupt history, because every time you would otherwise do so, the time machine mysteriously malfunctions and sends you to a useless time for your purposes.
I got the idea from my own interpretation of the "slipping" in the book To Say Nothing Of The Dog, by Author I Forget.
comments? flames? I'm curious what people think!
--
If you go enough generations then many, many people share the same ancestor. So this theory seems to say that none of this huge amount of people with common early ancestors would be "allowed" to kill any of them - or do anything which stops them pro-creating. This could not be prevented. Therefore time travel must be impossible. ( Unless there is a multiplicity of universes )
So, is this now obselete? I don't think so...! If I were to punch someone in the street, I'm likely to get into a fight, which will lead to injury, which meanstomorrow I'll be worse off. That's why I won't do it. If I drop a banana skin, chances are someone will slip on it and have a worse day than they would have ifI hadn't done that. Truth is, every action has a consequence. Which is why I think this "theory" is rubbish. You cannot go back in time and have no impact on the present. Just being there will attract someone's attention onto you. I'll prove it. Now you've read this, your brain has altered it's state in some small way. So what difference is there if I wrote this in the present or in my past? None. I have still made a change in your brain. *When* I wrote it is irrelevant.
I don't care for all these theories involving light etc. Once something has happened, it has happened, no matter where in the universe it happens or is observed from. You cannot undo something. If I kill you now, and then travel back 30 minutes, you won't be alive again. Real time travel is time travel as in Back to the Future. Which is simply impossible. If you take light and sight and sound and hearing out of the equation, then all you have is an absolute, universal time for every single event that occurs, and nothing and no one can change that.
I really don't get why people are always discussing time travel so enthusiastically, as if it is actually possible. I know that it is impossible just as I know that the sky is blue. It is just so obvious.
So, either everyone else here is stupid (which I acknowledge is highly unlikely), or I am missing something big here. Please enlighten me.
P.S. And let's not even start talking about travelling forward in time.
How about parallel universes? You'd kill your own grandfather, and you wouldn't exist in that parallel universe. But there would be plenty of others that you would exist in. Makes sense to me :)
Although the theory where you can't kill your own grandfather because fate stops you (i.e. the gun stops working) because it already 'happened' is also believable.
Maybe there is a flaw in my logic, but please, bear with me. I propose that any paradox based on causality is a paradox only in the human mind (and most likely, in the mind of any entity that follows a similar time-experience to our own)
'Causality' is mostly a construct of the human mind. Cause-and-effect matters to the universe only on a moment to moment basis, this instance determining the events in the next instance, which makes doing something like going back in time to kill your father a non-paradox.
If you travel back in time, you add your mass to the universe, matter an energy having been suddenly created as far as the universe is concerned at that moment. So now you travel to kill your father... the universe doesn't 'care' about where you came from, for the universe, cause and effect is all about the path the projectile takes to cause massive damage to your father's body, etc. So on that end, there is nothing constraining you against doing that.
Now you travel back to the present, removing energy/matter from the past, adding it to the present, and... although you have a perfectly valid drivers liscense etc, no matter how perfect your physical proof of yoru identity is, you no longer have an identity in our modern system, becuase you were nevr born.. this is where most people claim paradox. It is not, the paradox is only tot he human mind, which cares abotu where this person came from. The universe DOES NOT CARE.
The universe does not trace the person back through his travels. There is no true temporal paradox because the universe doesn't 'see' the paradox. The universe simply deals with you as a new entity that wasn't there before.
"It takes a very long time to count to 2 in binary." ~'Fourlegged'
The world will be a far better place when everyone stops talking about time travel.
Anyone who hears any scientist / teacher babbling about the theoretical possiblity of time travel should run screaming for a preacher who will fill their head with knowledge about how evolution is false and how God created the world is only 7 days just a few thousnad years ago.
Timetravel doesn't exist because Time doesn't exist.
Now where did I put that? Oh yes, here it is!
*bangs head repeatedly on brick wall*
DAMN QUANTAM MECHANICS!!!
...Had this been an actual emergency, we would have fled in terror, and you would not have been informed.
Here's the source article for those who want to read the physics involved.
http://arxiv.org/abs/quant-ph/0506027>
I wonder how the fundamentals of space-time are supposed to work with time travel? I mean, things travel through time, right? Wouldn't that mean that if you went to, say, the year 1950 you'd land in nothingness (or something completely weird like a dark matter universe) or something because the Earth is already somewhere in 2005? Or does Earth "extrude" through time, i.e. it's one HUGE snake that goes through space-time? Wouldn't that be against energy/matter preservation laws since as time passes Earth would extrude more and therefore the sum of mass in spacetime increases? Or does all of time already exist and the entire future exists as well as the entire past, with space-time being static in the end (kinda like a graph on paper, it represents movement but it doesn't move)? Wouldn't any change in spacetime require a "supertime" as well since spacetime can obviously not move through time but still would need "time" to change?
:p.
As a result, can we assume that the future is already "written" and "free will" is just an illusion, time paradoxes cannot occur because nothing changes, etc? What does our "self" perceive as "now", then? Is the world static and we just believe the past happened?
Personally I simply doubt time is a dimension but I guess we won't know. Especially if the universe is indeed completely static
Justice is the sheep getting arrested while an impartial judge declares the vote void.
The problem I have always had with backwards time travel is not the grandfather paradox but the conservation of energy problem. Let us assume that backwards time travel is possible. At the point I depart, I am made up of a certain amount of energy (in the form of a bunch of electrons protons neutrons etc). But if I travel back in time, the same energy would exist in some other form (be it me or the flower I pick for my grandmother). I would have thought that it is this duallity that is more difficult to deal ith than the grandfather paradox.
"The first thing to do when you find yourself in a hole is stop digging."
Hello! So if we could go back in time then somehow the universe we go back to will be constructed such that a) we can see it as ghosts, or b) somehow circumstances will always contrive to avoid a paradox in the future. What a bunch of bollocks. The beeb must be hard up for science news today.
I used to have a better sig than this, but I got tired of it
This is actually an interesting discovery, but the BBC News story doesn't do it justice. There's a better explanation on the New Scientist's website, and the original paper is available here.
wouldn't that mean that you could only go into a past where your observation wouldn't change your 'present'? So then the past you would be travelling to wouldn't be 'your' past, it would be to a past where there were possibilities of your presence being felt but not yet defined in your present. I really don't even know if that statement makes any sense...
I remember a short story where a guy meets another guy who has come from the future. The future man describes how the process of traveling to the past destroyed the universe, but "it was worth it." When asked from how far in the future he came from, he looks at his watch and says "twelve minutes." Last line from the first guy: "It wasn't worth it."
Well, I thought it was funny.
You people are overcomplicating things.
If you manage to go back in time and kill your grandfather, it means that your gransmother was doing the guy next door.
Simple.
No, the old model, where changes to the past are permitted, is true.
All the changes to our past have already occurred.
How else do you explain the Rennassiance, crop circles, or the absence of WMD? The only reasonable explanation is obviously the actions of future activist agitators and pornographers.
It also explains Intelligient Design... and who created the Great Designer. He was probably some megomaniacal schmuck from 2305 during the period of the Third Great Crusade and Inquisition setting the dials to zero (and voiding his warranty). Funny, those time travelers never seem to learn from the past.
"You have liberated me from thought."
If you do something that would create a paradox time 'splits' and creates a new timeline/dimension. If you left in timeline A you return in timeline B. Simple :)
If Google really cared they would fix Android Chrome to reflow text, instead of discriminating
http://xxx.lanl.gov/abs/quant-ph/0506027
Abstract:
We introduce a quantum mechanical model of time travel which includes two figurative beam splitters in order to induce feedback to earlier times. This leads to a unique solution to the paradox where one could kill one's grandfather in that once the future has unfolded, it cannot change the past, and so the past becomes deterministic. On the other hand, looking forwards towards the future is completely probabilistic. This resolves the classical paradox in a philosophically satisfying manner.
The world is everything that is the case
You can't change the past,thus you can't change you. or any one else , nor destiny nor fate
no matter how hard you might try., No matter weither you like it or not
thus you can't change you're future..
Sucks, but true,
Believe me - I know, I've tried
So many times to KILL myself.
To prove it.
Literally
Like walking in fast moving cars and shit
But Still I'm alive when theoretically
I shouldn't be.
By all forces of nature.
----
unscientifically however, I do believe
you might be able to "view" the time space
continum from an external point of view.
A break in the consciousness loop.
If you were to alter time
The whole existance of man-kind (an oxymoron)
Would Implode in seconds
nothing you can do about the past,
nothing you can do about the present,
nothing you can do about your future.
Fucking with time,
means all man kind ceases to exist.
Simple as.
Time travel works now?
what's all this "killing your father" theorizing :P anyways it still leaves alot of stuff
anyway? i'd rather go back and hand myself a nice
financial times of today. sheesh!
i guess it' just not possible 'cause going back
would "erase" all your memories. i guess going
back before you where born would leave you in a
kind-of brain dead state. if you go back and met
yourself at say age 17 years you would probably
have exactly the same memories like you had when
you where 17? so i guess it's a good idea to start
growin up really fast and having that tought of
going back thru time at a relative early age,
since if you didn't have that thought at age 17
and you went back you wouldn't know what to give
yourself
open, like what would happen if you went back and
died? or would you be a kind of superman that
because of the quantum probability of not being
able to kill your father in the past, you in the
same way couldn't die in the past?
well it's all wierd anyway. with this humungous
black hole at the center of our galaxy and having
all these solar system and stuff spinning around
it (add up ALL the mass in our galaxy then
calculate how strong the gravity in the center
must be!woah!) maybe our perception of a clean
arrow of time is all wrong? maybe time travel
happens all the time, maybe we're living in a
"polluted" time/space already, that sometimes
flops/flips over it self (back for milliseconds,
seconds, minutes)? well i sometimes do get the
feeling something is going to happen (say a
freaking cat is going to suicidely cross a busy
main road, a insect going to hit my visor, all
this at least one curve before the acctual
location) and it does happen sometimes...
I made an attempt to explain this at the MIT time traveler convention. But I couldn't get in the door. I guess I'll have to try again.
Time travel take more energy than most of you seem to realize.
...I was playing Kill Dr. Lucky, only I could never win? Man, that sucks.
don't think einstein would like his face being near this stuff
some folks believe conscious is the bridge between classical and quantum models.
The one that does work was actually explained in DBZ. You can go back in time, and kill yourself. A new timeline will be created where you're dead, and the old timeline will still exist, but be inaccessable. Now since the timeline you came from still exists, so do you. But if you go to the future, it'll be one where you're dead.
Then there is the continuous timeline theory where there is only 1 timeline, and all time travel has already been done the first time. If you're going to go back in time and meet yourself, there will be no timeline where you havent met yourself. You'll meet, you'll know about it, and then later you'll go back and meet yourself again
i thought '12 monkies' already stated this fact?
- Null theory- the only time travel that can be accomplished is traveling forward in time by passing through all the moments between now and the future.
- Single timeline, no changes possible- Everything is predestined in such a way that anything you do in the past will have already been taken into account. Your actions in the past will bring about the future you're familiar with.
- Single timeline, changes possible- You can change things in the past, but be careful making any changes that would prevent you from going back in time and making those changes. That would lead to a paradox, and who knows what happens then. Maybe the universe is destroyed? (a popular theory for something so speculative) Another lesser explored possibility here is that of spontaneous creation/destruction within a time loop (i.e. I go back in time and give myself something that I have because I went back in time and gave it to myself. That object then only exists within the loop of time, and is already infinitely old.)
- Multiple timelines, creational- traveling back in time automatically creates a new timeline, and all the changes you make go into the events in the new timeline. Since you're from the old timeline, which isn't being changed, no paradox is possible.
- Multiple timelines, preexisting- This model is the same as the last, but supposes that every possible timeline "already" exists, so when you travel back in time, you're not "changing" anything. The distinction is minor, since talking about in what form a timeline "already" exists treats timelines as though they exist "in time". But it might make a difference if you wanted to talk about jumping into an alternate timeline without traveling backwards in time.
Most science fiction mixes these models haphazardly, so instead you get an inconsistent model of time travel....we cannot do much in the past anyway because we are not just talking of one event that should be complimentary e.g. the person who time traveled was born, but of many events e.g. the actual position of the atoms, etc.
One of the things I like to think about are the limitations of rationality. Rational thinking involves ignoring most of what's true about something, in order to deal with the aspect in which we're interested. When we're thinking about a chair as something to sit on, we're not really thinking about it as kindling, or as potential building supplies for a chair pyramid, nor the possibility of using one of the chair legs as a club. We tend to think about just one property of an object at any given time, which (temporarily) blinds us to its other properties.
I really wonder if the whole time travel metaphor thing isn't an artifact of bad modeling, rather than anything true. Time is often claimed to be 'a dimension'. A one-dimensional object is a line, and a two-dimensional object is a plane. Three dimensions is real life, what we see, and the fourth dimension, ergo, must be time.
This is all very pretty, but there's one big problem... there are no one- or two-dimensional objects. Nothing in real life has less than three dimensions. Never, never, not ever. One and two dimensional objects are imaginary, they do not and can never exist. Dimensions are a highly useful mental model, but since there are NO objects with less than three dimensions, there's a good chance they're not actually true in any meaningful sense.
Like most rational thought, dealing with space in terms of wholly imaginary dimensions allows us to do some really amazing stuff. But it also blinds us to most other things that are true about the universe while we're thinking that way.
I very strongly suspect that time is not, in fact, a dimension, and that all the mathematical hand-wringing that goes on about time travel is trying to make an impossible thing work out of a false, imaginary premise. There are no one- and two-dimensional objects. Objects always have height, depth, and width. Always.
If the first and the second dimensions are imaginary, it seems entirely reasonable to assume that the fourth must also be imaginary. We like to count up, and having invented three dimensions, we may be looking for a fourth. It looks to me like we're confusing our map for the territory.
I strongly suspect that ultimately we'll find out that time is a force or a process, and that the model of it being a line we're traveling along is false.
my last post should have read it would NOT effect your timeline
Everybody seems to take for granted that if you travel back in time, you end up on the same spot as you left, or at least some place on earth.
It's very convenient, but is there any logic behind this? What reference point in the universe decides where you end up?
Think about it, our earth is spinning around it's axis, the earth is revolving around the sun, and our solar system is moving at high speed through space together with the rest of our galaxy.
'Here' ten years ago is in a cosmic perspectice physically nowhere near 'here' today.
So without any reference point, where do you end up after travelling back in time? And if there is a cosmic spatial reference point, what is it?
Even the molecules in your body has large been changes the last ten years, so they can't be a really good reference point either?
In my opinion time travel does not make sense on more levels than just the grandfather paradox.
Superman knew he could not change the future.
to marry the Grandfather paradox with Schroedinger's cat.
There is no vast cosmec conspiracy against time travel. What these guys are really saying is that time travel is possible only in a limited set of circumstances.
If you go back in time to kill your father (or even yourself), you won't be able to. It's not that you'll be hit by a car, or that the gun you bring with you will fail to fire. You just won't be able to go back in time in the first place.
Kind of like you how you can't walk through walls in normal space.
Great theory, well thought out, etc. etc.
But what the hell is with the recurring references to killing one's own father? To be honest, I wouldn't mind offing mine, but I'm sure that sentiment is in the minority of people. I just find it weird that this scientist keeps going on and on about killing one's own father. Methinks he may have issues there.
And as a side note, what a great f'ing job. Sitting around hypothesizing about things that will never be able to be proven one way or another in your natural lifetime. Awesome way to earn a paycheck. Good on ya, man.
If you travel to a time before your birth, your very presence will change the weather via the butterfly effect. The weather effects our behavior which effects when we do certain actions. If your parents have sex at even 1 second later, a different sperm will make their child effectivly killing you.
In fact, if you travel to a time before you travel, you'll effect your local weather, changing your actions slightly, amplifying it with each itteration, making it impossible to travel into the past.
UNLESS the action of traveling to the past puts you into some sort of "protective time bubble" where your own personal past is set, unchangable while you're in the process of time traveling. But if that where to happen, you'd keep going into the past and millions of yourself would keep apearing in different areas as you change the future slightly. Bummer.
"That's so plausible, I can't believe it!" - Leela
This is old news...already ancient in cosmological / quantum / theoretical ideas...
because if you can't now go back and kill your own father, or even alter his life in a significant way, then i would propose that you couldn't alter the lineage of anyone else's grandfather currently alive today.. including... the grandfather of the weed growing out from under my front porch, and the great great grandfather of the storm that came through Portland last night, and I wouldn't even be able to alter significantly the grandfather of the air molecule that carried anthrax to the nose of that old lady in connecticut soon after September 11th. So this really says that you cannot alter *anything*, because you would be altering the lineage, or trajectory of any molecule that made up any existing object (including the cells in your possibly now-dead father's arm, even if he died before you went back!
so i guess then I could watch the past on TV, but never go there..
-K
He's obviously got a lower usernumber than me.
And it's just about the best example of the principle of a local maximum (and the real meaning of the phrase "it has to get worse before it will get better") that I can point people to.
Observation necessarily modifies the equation. An example is looking at what is going on. To do this you need some sort of photoreceptor that is soaking up light. That is light that would have gone somewhere else had you not been soaking it up. This light would have heated the environment had you not been there soaking it up. This very tiny change in heat becomes a larger and larger change as the years go by. Every little things adds up over time. Even ghosts would leave trails that can widen into canyons.
that you cant, but that if you had, you wouldnt have been born. Eg, whatever time travel has/will occur into that past, has *already* happened, and if someone went back and killed someone, they already did it (even if the time they left from is in the future, relative to our current idea of the present).
:P
Ooh.. its all twisty.
what if you hired someone to kill your grandfather, someone who didnt know if he was alive or not at the present.
I came up with this exact same theory years ago.
And it was brought up in the movie The Time Machine.
So either way, they're a little behind...
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How the hell do you research this stuff? This is the realm of potheads, isn't it?
Robert Heinlein wrote a story
"By His Bootstraps"
Where a guy was not only his biological mother but his biological father as well.
Diplomacy is the art of saying "Nice doggie" until you can find a rock. Will Rogers
If everything already measured now prevents anything in the past from happening, & if a past actually remains after it has departed, then there has to be a future as well. If something measured in the future cannot be changed in the past, then aren't we in essence predestined based on the actions of our decendancts? Is this a quantum explanation for Fate?
And what conclusion would you plan to draw from the fact that something never existed?
Arriving in Central Park, NYC, a physicist observes a butterfly flapping his wings wildly and then gently stops it, preventing a typhoon from brewing up over Japan seventeen months later. Or does trying to do so cause the storm? After all, no matter how fast one can reach for a butterfly, unless one has a butterfly net, the li'l beastie will flit away faster than one can stop it. In other words, it seems clear, considering the number of hurricanes and typhoons this planet has each year, that time-travelling physicists wildly chasing after butterflies in New York cause more air disturbances than just leaving well-enough alone.
I think we need more psychiatrists in Central Park than police.
Well you can actualy change the speed with wich you travel to the future. Traveling faster within the first 3 dimentions makes you travel faster in the 4 dimentsion as well. Just as well as placing youself close to an object of significant mass.
All of corse reletive to the objects surrounding you.
But then again: You are right that traveling backward is the real problem.
42.
The easy part was getting the brain out, but the hard part was getting the brain out.
Let us assume that it is possible to travel back in time affecting the past in only complimentary ways. This would suggest that the present is static, it cannot be changed by modifications made to the past. Therefore, a person who travels into the past would have knowledge of what would happen in the present. Now let's change perspective for a minute and stand in the shoes of the person in the past, that person would therefore have to arrive at the same point in the present. Whence the person in the past has no free will. Now if the theory (which is very poorly represented in the article) were to suggest that the time traveler were only a phantom in the past, unable to enact on the past in any way (not even able to be seen by those in the past) and that that person were just viewing the past like a movie, I may be able to accept the argument. For then rather than the past being reenacted, the time traveler is merely reviewing previous events.
I've always wondered why that sort of view isn't more popular or at least widely recognized as a reasonable alternative to the "quantum magic" view of the world. It's philosophically more reasonable while being mathematically identical.
When I was taking undergraduate quantum mechanics (about 8 years ago), I recall feeling elated when I ran across a single paragraph in the textbook that referred to the possibility that one day someone might develop a non statistical theory for the workings of the sub quantum world.
It probably would be pure fantasy since there's no way such a theory could ever be tested (right?), but I was happy to see that it was at least acknowledged that the statistics are just a tool and not a philosophical statement about what the universe is.
Cow Cube
why are we under the impression that the perceived state transitions of energy and matter can be reversed (i.e. time travel) The passing of time is a concept created by human thought to allow us to understand this transition, nothing more nothing less. so the concept of travelling back to a point in space that a clump of matter or energy was at previously is not possible. State changes of energy and matter are forward flowing by their nature, and cannot be reversed ... Well that my 2 cents worth anyway.
-= Technomancer =-
Your very presence in the Past would change the Past. You can't be complimentary and effect a change in the weight, the number of humans present, the amount of air being breathed, at the same time. Therefore attempted travel into the Past would fail. Either yur atoms would be scrambled (in the Present) at the moment the Past detected your attempt, or you might start going into the Past but find yourself deflected away somewhere else... most likely into Space somewhere and DIE. It might even be much worse than that. You could find yourself trapped somewhere in my website, and we all know what that would be like. Well, at least I do: http://tinyurl.com/dc8ul for information about Space Travel.
- When you go back in time, how far away from the original position will the Earth be? After all, the solar system is spiralling around the galaxy.
- If you have a 1960 penny in your pocket when you go back to 1961, will you not be violating mass continuity by having the same atoms in two different places at the same time?
There are plenty of memories I don't want to relive, but proving you can't kill your grandfather seems like they are solving a problem that assumes a ton of other much more severe paradoxes have been solved already."Who are you?" "No one of consequence." "I must know." "Get used to disappointment."
try and remember the advice dad gave me on my wedding day..
"if you ever travel back through time, don't touch anything because even the slightest change could alter the future in ways you couldn't possibly imagine."