Talk:Time travel/Archive 2

message: If you go back in time to stop a disaster from happening, and you succeed, why is there any reason to go back in time to begin with?  Which means you never go back in time to stop the disaster, which means it does happen.  Just wondering if this would create some type of infinite time loop?
:The questioner is making the assumption that going back in time to change a past action will lead to the SAME reality changed.  You could now be in a new reality, which has split off from the original, with no way to get back to where you came from, because the path back there has been changed, unless you can go back and undo the change. 
:There is also the issue of whether the person who decides to go back, or not go back, has any personal memory of the trip, depending on the vehicle of travel back. User:AlMac|(talk) 16:54, 3 January 2006 (UTC)
replies: text: Also, if time travel is ever created, we will have already known it because if someone came back at this exact moment, and they told us about the future, we will know if there is time travel in the future. Therefore, you can almost assume that the future has already happened.--Weatherman1126 22:23, 9 February 2006 (UTC)
thread_title: Question/Something to Think About

message: The definition of time travel given from this site sounds like dreams to me... Although it isn't very controlled, perhaps like our conscious body moves physically through space, our subconcious moves mentally through time and alternate universes. What do you think? —The preceding unsigned comment was added by Jebus96ae (talk • contribs) on 07:31, 14 February 2006.
:Many claim to have Déjà vu sourced in dreams that are of future events which they later experience, is this what you mean? A laymens theory to this (if taken outside the general psychology of it as only being an illusion) could align itself with quantum theories which claim particles travel through time regularly on the highly microscopic level, and that this somehow interacts with brain firing mechanisms such as neurons when the brain is in the receptive sleep mode. Which would require that there be some space-time loci in physical matter, such as that composing the brain, which anchors this energy transference to a single place (ones brain) through time; and is a form of movement of "information only" through time. Otherwise we're speaking of either A) exotic matter and the mind, i.e. an exotic matter composing the subconscious (and there is no reason to believe this), or B) a metaphysical belief that the subconscious mind is separate from any matter composing it, even that it posits matter itself rather than the other way around. A little off topic for the time travel discussion page I would think. 67.5.156.138 02:50, 28 April 2006 (UTC)
thread_title: Dreams Time Travel?

message: Moving at a faster rate of time into the future as an object moves faster relative to another has been experimentally confirmed, such time travel isn't under question and it creates no paradoxes etc. The article contradicts itself on this point, mostly due to a lack of clarifaction between moving forward and backward in time.
:There's a novel by Steven King, I forget the title, in which some Nazi scientists invented time travel, and sent explorers into their future, our present, to steal future technology, to help them win WW II.  They were ultimately defeated by sending someone to the British who would be believed about the importance of bombing the laboratories of the Nazi Time Travelers. In my opinion, this novel illustrates the notion that changes to history can cause paradoxes, even when the travel is into the future. AlMac|(talk) 04:54, 21 September 2005 (UTC)
replies: text:  No - the only way for that to change the past woud be if they were able to send the information they obtained back to the past, which would require backward-in-time-travel (for information, if not for mass). --Cheese Sandwich 18:42, 29 September 2005 (UTC)
replies: text:  The novel you're referring to is actually Lightning, by Dean Koontz, not Steven King. Doctortoc 18:50, 25 February 2006 (UTC)
replies: text:  Perhaps I oversimplified.  The Nazi agents were in combat with a double agent who was trying to undermine their actions.  They were jumping backwards and forwards in modern times, seeing some event, going back and killing some people so the event would not take place.  It was not a one time dimensional novel. AlMac|(talk) 00:48, 30 September 2005 (UTC)
thread_title:  past vs. future time travel 

message: An article on Time travel and no mention of Dr Who or Isaac Asimov's The End of Eternity - "Shurley shome mishteak" as they say.
Time travel can be described as the ability to move through time in a non-linear manner (such as we do and space ships are assumed to do).
:At one time there was an extensive section in this article on Time travel in fiction, Hollywood, Games, etc. and that got moved to a separate article on Time Travel in fiction (see links on the article) with Time Travel as scientific fact getting to adopt the main article. AlMac|(talk) 07:11, 26 October 2005 (UTC)
replies: text: Editors arrive at articles and enthusiastically add material.  From time to time chunks of info on the summary of fiction on the main Time travel (in science) article should be moved and merged into the Time travel in fiction article, with suitable explanation to avoid getting into an edit war with the new enthusiasts. User:AlMac|(talk) 16:58, 3 January 2006 (UTC)

text: Heh, KarlBunker beat me to it :-) Weregerbil 15:29, 27 February 2006 (UTC)
thread_title:  fact v.s. fiction 

message: It would be nice if there was a seperate section that addresses What is Time. This would help when discussing Time travel from a scientific grounding and then how it relates to science fiction. Also its usefull if 'personal theories' are excluded as this goes against the wikipedia guideline and at the very least confuses things. 86.7.107.45 18:22, 6 November 2005 (UTC)
replies: text: There is a separate article on Time theory. Perhaps better linking needed to make it more obvious what articles exist, so we can collectively work on improving them all. User:AlMac|(talk) 17:06, 3 January 2006 (UTC)
thread_title: An approach to clean things up

message: Most authors see time travel as a change in the time coordinate of the entire universe except the time traveller. This vision is wrong.
Any device allowing time travel may only change the time coordiante of the traveller while the universe goes about it's business. Thus time travel will happen in one of the following ways:
* The traveller slows himself on the time coordinate and the universe will sped by him, which can be considered a travelling into the future;
* The traveller accelerates on the time coordinate and will grow older much faster, with the posibility of super-human speed in relation to the rest of the universe;
* The traveller reverses the flow of time for himself, which would make him younger, reverse cause and effect localy within the time-machine, will result in a younger version of the traveller in an older universe, an extreme form of traveling into the future.
If this is the correct frame of reference, then, theoretically, travelling to the past is impossible as the past does not exist. The universe is in the present and the whole universe would have to be reversed in time while the time traveller keeps his time coordinate, as this seems impossible without god-like powers it should be dismised as an option for a time machine. 
I haven't seen this idea formally presented, so I'm putting it in here. If somebody has some comments and/or references please add them.
Richard1984 12:10, 21 December 2005 (UTC)
replies: text: This is only one of many possible interpretations of time travel. In particular, it overlooks the classes of travel where either a) the traveller's worldline is discontinuous (vanishes at the departure point, appears at the arrival point, always proceeds normally otherwise), or b) the traveller experiences time normally relative to the patch of space they're embedded in, but events inside and outside this patch of space seem to experience time flowing in opposite directions relative to each other. Both of these allow travel into the past (relative to some arbitrary inertial frame) without de-aging the traveller. See also closed timelike curve and the "time hole" implementation of a wormhole (which can result in a CTC). Both of these produce spacetime geometries where an object's worldline can intersect itself (allowing "future" and "past" versions to meet). --Christopher Thomas 15:47, 21 December 2005 (UTC)
replies: text:  In one of my favorite Time travel in fiction stories, there is a multiverse of multiple universes, or realities, where the traveler is able to move from one universe to another.  The arrow of time is going in a different direction in different universes.  In the story, we can only travel in the time direction of the universe we are in at current time, but we can have two universes traveling in opposite time directions, at different time speeds.  So you go thru a "portal" to another universe, travel forwards in time a month there, to a different portal, and you end up 100 years in the past in the original universe, without traveling in time per se.  I think this kind of discussion should move to Time travel in fiction or to some other main article, from the dsicussion of what our current science believes is possible. User:AlMac|(talk) 10:06, 2 January 2006 (UTC)
thread_title:  Most time travel ideas have the wrong frame of reference 

message: This article needs a section on the philosophy of time travel, since it is as much an issue of metaphysics as of physics. (That is, whether time travel could be possible, not just whether it is possible.) For example, the word of Paul Horwich. Ben Finn 18:18, 30 December 2005 (UTC)
replies: text: Check out the Wiki article Philosophy of space and time.  Is this what you were looking for?  Perhaps the interlinking could stand improvement, so it is obvious what all related articles exist. User:AlMac|(talk) 17:10, 3 January 2006 (UTC)
thread_title:  Philosophy section required 

message: my opinion is no one can change the past no matter how they try.
assume that you go back to the past to change something, but no matter how you try it you wont be able to change it. its like on minority report, tom cruise found out that he is going to shoot a guy, then he did everthing he can to prevent it, but in the end he still shoot the guy
202.170.56.242 06:42, 6 January 2006 (UTC)
replies: text: If you could go back in time is it even possible NOT to change the past? Just by being there, you have changed the past slightly - you've breathed the air, your body has refected light in a slightly different way than it would have been reflected if you had not been there. It's true, these are tiny changes, but changes nonetheless. If you walked into a store, and bought the last doughnut, that's a change. Small changes can build up to larger events.--RLent 18:30, 16 February 2006 (UTC)
thread_title:  wont change it 

message: The article Intelligent designer includes a reference to time travel in Prof. Michael Behe's book Darwin's Black Box, which challenges the theory of evolution.  The author suggests that a time-traveling cell biologist could have been the originator of human life.  Any thoughts about if (and where) a reference to this item from science/pseudoscience/religion might be included in the time travel entry??   JXM 09:47, 15 January 2006 (UTC)
thread_title:  Time travel & intelligent design 

message: There is so much potential and interesting material (both scientific and fictional) on paradoxes with time travel that a new Time travel paradox article would be a good idea to pull it all together (imo). There is a lot of work in quantum theory which looks to a layman like me to suggest that actually we're not actually certain what is happening or not happening in the present and you can set up experimental conditions in such a way that particles will both do something and not do it. 
It could be that paradoxes are just another weird quantum effect which when you look at something on a macroscopic scale just cancel each other out (for all intents and purposes). So in theory there are an infinite number of possible pasts for any present but in practice we all observe basically the same past. If we used some quantum device to travel back our actions would cause the possible pasts to collapse into the one past which would match the one observed from the present. We obviously cannot conceptualise of being in this state as we interact so profoundly with the universe all the time but we are nevertheless a product of quantum mechanics like everything else and yet it still seems completely alien to our everyday observations of the universe.
[[Btljs 22:02, 16 January 2006 (UTC)
thread_title:  Paradoxes 

message: I've done a lot of edits to this article recently, and reduced its size a lot in the process. I think it's a much better article now; a coherent piece that someone could conceivably read from start to finish and feel that they got something out of it.
My thoughts on why so much of the article deserved "throwing away":
In general, Wikipedia articles tend to collect cruft over time. People do a quick read and think "Oh! I'll add my thoughts about xxx!" Without necessarily thinking carefully about whether their addition adds new information. I think an article about time travel is especially prone to this, because it's a fun subject to think about, but a difficult subject to write clearly and meaningfully about. It's easy to think that one's own thoughts (or the thoughts from some movie or book) along the lines of "hmm, maybe time is like this" are new and meaningful and a worthwhile speculation. Also, the very length of the article was probably encouraging people to make unnecessary additions to it. It was a chore to read all the way through, and some people undoubtedly went ahead and added stuff without reading all of what was already there.
KarlBunker 18:26, 27 January 2006 (UTC)
thread_title:  major trim-down 

message: Expect regular changes which revolve around the safety of time travel. Note to whomever is doing the reverts here: you missed two "safety not guaranteed" refrences, and I suggest you simply lock it. Penis Gourd 08:16, 8 February 2006 (UTC)
replies: text: I was browsing ytmnd (yes I'm a ytmnd'er, but I don't vandalize wikipedia), and I saw this on the top 15 atm:
timetravelingsafety.ytmnd.com/
Expect more vandelism all day to-day. (Bjorn Tipling 18:36, 8 February 2006 (UTC)

text: And semiprotection was received. Thanks to howcheng we can rest from constant rvv's for a while. --GunMetal 21:58, 8 February 2006 (UTC)

text: Image deleted
If any references to YTMND is not included then all other fictional references should be erased. - GWatson
The fad should be referenced once, and only once, in the list of references.  Fair compromise. Crazyswordsman 17:07, 16 February 2006 (UTC)

text: Why should it be referenced here? Aren't things like this fad already covered in the mental retardation article? KarlBunker 17:43, 16 February 2006 (UTC)
thread_title:  YTMND WARNING 

message: Why would anyone vandalism on this page?
Internet Meme on YTMND --Stilanas 20:19, 8 February 2006 (UTC)
replies: text: In our current reality universe, in any sub-group of humans, we have people of good will, people who have nothing better to do with their time than cause trouble such as vandalism, and people who are interested in neither, they just want to make money or satisfy their needs.  Fortunately we have enough of the first group of people at Wikipedia, to overcome the damage from the second. User:AlMac|(talk) 06:32, 9 February 2006 (UTC)
replies: text: YTMND isn't trying to 'cause trouble.' It's just a joke, you should stop taking yourself so seriously. (Bjorn Tipling 07:22, 9 February 2006 (UTC)

text: Please see Wikipedia:Vandalism for a definition of what is considered vandalism on Wikipedia. Inserting nonsense into articles is one of the items listed. Just like scribbling in library books, you are making a resource less useful and are making work for the people who have to fix it. The joke on YTMND is quite funny; but cutting and pasting it _here_ isn't. --Christopher Thomas 21:20, 9 February 2006 (UTC)
thread_title:  Vandalism? 

message: Firstly, Back to the Future Part II's time travel does not truly fall under the alternate-timeline-creating time travel type (labeled here as 1.3) and thus should not be used as an example of one. All of the time travel throughout the Back to the Future trilogy alters the timeline in a ripple effect which moves progressively forward from the point of the change (suggesting some form of time beyond normal time in the process). This is best seen in the first movie when after Marty accidentally breaks the series of events that would lead to his own birth, he is not immediately removed from the timeline. Instead the changes slowly progress forward, visible via the family photo Marty has in which first his older brother fades and disappears, then his older sister (younger than the older brother) follows, and finally Marty himself (both in the picture and his actual body) begins to fade from existence.
The time travel in question in Part II, when Biff from 2015 travels back in time and gives his 1955 counterpart the Sports Almanac is also of this type. Though technically non-canon, due to its being cut from the theatric and home releases of the film, Biff was originally to be seen fading from existence just after returning to 2015 and stumbling out of the DeLorean. This was removed because it would probably confuse the audience (no direct in-film explanation is given), but can be seen on the deleted scenes on the DVD release. The commentary explains that the reasoning was that in the altered timeline Biff dies long before 2015 (possibly killed by Loretta).
The only question then is why Doc, Marty, and Jennifer are unaffected by the ripple. One could propose that they are unaffected because they travel back in time past the ripple, but if the ripple had already reached a point where Biff had died before they began their trip back they should have already been affected... Unless the ripple's ability to effect things outside of their own time frame when it reaches their correct time frame only works on things that are in the past, where the ripple has already been.
The other problem I need to point out is another type of time travel not mentioned in the article at all: the so-called "predestined" time travel. This is the kind where anything the traveler does in the past had already occurred according to history before they even travel back in time. This results in an apparent lack of free will, which is a large reason why this type is disliked by many fans. Interestingly, this type of time travel could be considered both paradoxical in nature, since activities of a time traveler in the past can lead to events which caused them to make the trip back in time in the first place (and thus the trip caused itself to occur), and it can also be considered paradox-free because the timeline is never altered in any way. Typically this means that an author/writer would need to put a lot of forethought into the storyline for this to work well. One example of a series that pulled this off fantastically is Babylon 5.
JDavis1186 01:27, 9 February 2006 (UTC)
replies: text: The second point was covered under "immutable timelines" the last time I checked, but I haven't done a detailed review of the article in quite a while. --Christopher Thomas 07:41, 9 February 2006 (UTC)
replies: text: I seem to have accidentally skipped over the given example of predestined time travel (From Harry Potter and the Prisoner of Azkaban) on my initial reading of the article. This brings up a different issue, though, as predestined time travel is quite different from time travel where events mysteriously conspire to prevent paradox (the other example under 1.2), and should not be labled as the same type. Perhaps 1.2 should be split into 1.2.1 and 1.2.2. JDavis 20:36, 9 February 2006 (UTC)
replies: text: The whole article could actually use a rewrite (at least, as of my last review of it), but I'm not in a position to be able to devote that amount of time to it now. If you see a way of improving it, by all means go ahead (though it's best to propose _major_ changes here to see if there are objections rather than implementing them without discussion). --Christopher Thomas 21:18, 9 February 2006 (UTC)
replies: text: Well, as I have only just registered, the lock is preventing me from making any edits at the moment. JDavis 07:07, 10 February 2006 (UTC)
thread_title:  Problems with the "Types of time travel" part of the "in fiction" section 

message: I feel like I'm taking crazy pills.  These sentences fight all flow and it really takes me out of trying to understand the article.
"The theory holds that, relative to a stationary observer, time appears to pass more slowly for faster-moving bodies: for example, a moving clock will appear to run slow; as a clock approaches the speed of light its hands will appear to nearly stop moving. The effects of this sort of time dilation are discussed in the popular "twin paradox" which asks the question, "If two twins are moving relative to each other, they will each appear to the other to have aged more slowly. But when they reunite, how can each twin be younger than the other?"
A second, similar type of time travel is permitted by general relativity, where a distant observer sees time passing more slowly for a clock at the bottom of a deep gravity well, and a clock of an object lowered into a deep gravity well and pulled back up will indicate that less time has passed than the distant observer's clock."''
I purpose changing the text to the following:
"The theory holds that, relative to a stationary observer, time appears to pass more slowly for faster-moving bodies.  For example, a moving clock will appear to run slow as a clock approaches the speed of light; meaning the hands on the clock face will appear to nearly stop moving.* *This last sentence is repetitive, but is it so for elaboration?* The Twin paradox elaborates further on this phenomenon."
"A second, similar type of time travel is permitted by general relativity*, where a distant observer watches a clock at the bottom of a deep gravity well, and then lowers another clock into the deep gravity well, but then pulls it back up showing that less time has passed than the clock at the bottom of the well." *Isn't the first example of general relativity as well?
I hesitate instituting the changes myself as I am not an expert at these thought experience of have rudimentary knowledge of the subject.  I wouldn't want to alter any of the elements of the experiment inadvertently to satisfy my need for better grammar.  So I’m sandboxing it and hoping someone can either verify or suggest how to go about altering these sentences for greater flow.  Thanks.  Bear77
:With regard to the first paragraph, I agree that the twin paradox description is probably too compressed to be understandable on its own. The simple link sentence you show would be better. Other than that I think the 1st paragraph as it stands is better. The 2nd paragraph could be improved by removing "of an object" from "a clock of an object". Otherwise, I think it's about as clear as it can be. Now you know why physicists who think about this stuff for a living always have funny-looking hair. I'll make those changes now. :-)  KarlBunker 18:46, 10 February 2006 (UTC)
thread_title:  Help Me Clean these Sentences 

message: Paradoxes are impossible! If someone were to go back in time and change something, it would not create a paradox because what he or she had changed would have already occured, whether we realize it or not. If someone were to stop JFK's death, he or she could NOT do it because it would have already occured and whatever he or she would have done would have occured already and what should have happened, would have happened. It's kind of creepy to think about it like this, but time is already set in stone. If someone in the future comes back to our present (which is already made), it would be his past, and he would have already done everything to affect his future and our present in our future and his past.  
Also "If you go back in time to stop a disaster from happening, and you succeed, why is there any reason to go back in time to begin with?  Which means you never go back in time to stop the disaster, which means it does happen.  Just wondering if this would create some type of infinite time loop?", no, it wouldn't, because you would have already done it. You can't stop yourself from doing something. Even if you go into the future and kill yourself before you take the trip, you will still do it, because you  have to be there  in that space/time, no matter if you do everything in your worldly power to stop it because you know you just took a trip to kill yourself and you come back into the past armed with this knowledge, it would be "your past" even if it was in the future, because you would already know you were there, you would already have to kill yourself and you could do nothing to avoid it. No matter how much you try, when you kill yourself in the future, you will be there in that space/time when you killed your future self. And even if you had armed yourself with this knowledge, knowing the exact time when you would die and where, and done everything to prevent yourself from going to this place, you would have to be there, because your past already knows you were there and your future will not change, because it would have already occured.
Now lets take the opposite of this. You, in the future come to kill yourself in the past. Well, since you exist in the future, you must have survive your killing in the past. Otherwise, you could not exist in the future, and therefore could not come to kill yourself in the past. But since you know you exist in the future, it is impossible for you not to exist and therefore, you do exist in the future because you know it has already occured (wow, that is creepy, knowing that the future will occur). 
Let's take you for a second. You just read my opinion. You know it happened. Is there anything you can do to stop me from writing this article? No, it exists now, which means it existed then and it will continue to exist unless I am moderated or Wikipedia dies (XD). 
In theory, time could be represented as one dot. Each person has their own individual dot. The dot is made from experiences, all which occur at the same "time", from a perspective of someone observing the dot. From the human perspective, the events occur in sequence, knowing the past events, acting out the present events and not knowing of the future events. Every action we do is predetermined. Everything about that dot has already occured, whether the person that the dot represents realizes it or not. From the viewing perspective, every single thing in the universe would all occur at once, which may be beyond the human mind. There would be an infinite amount of dots, all being created at the same time. An infinite process occuring in a infinite amount of "time" with the time being represented as 0.000000000000000000000000000000000000... with no one in sight, forever. Complicated, isn't it?  
I think it's all time we give up on these childish games of parallel universes where Martin Luther King Jr. isn't assasinated, the U.S. loses the Revolution, or life never occurs on the Earth at all because someone killed some microscopic creature while time traveling. No matter what point in time you are, it's somebody's past. And they already know what should happen, what will happen and what does happen.
CherryT 06:01, 12 February 2006 (UTC)
replies: text: That is one interpretation. There are others, many of which are also self-consistent. These are all described in the article. The point of the article is to describe all of these interpretations, vs. assuming that any specific one is correct, as they all occur in literature.--Christopher Thomas 07:34, 12 February 2006 (UTC)
thread_title:  Paradoxes DO NOT exist