Time Travel

[devonin]

Perhaps so, but who says you're going to fail?

The fact that Bob is dead says you fail. I thought this was pretty explicitly stated.

[Bynary Fission]

Originally Posted by devonin

The fact that Bob is dead says you fail. I thought this was pretty explicitly stated.

I know. I stated that you aren't necessarily going to fail. Read my post again, I explained why.


~Bynary Fission

[cry4eternity]

Originally Posted By Bynary Fission:
There was a man named Andrew who said he traveled from the year 2246 to make a fortune off the stock market with his future knowledge of it's trends. To be exact, he made a jaw-dropping 350 MILLION dollars in two weeks. He was investigated, where he made his case. No records of him were found before he appeared.

Did a little research (wikipedia :P) and found this:

Wikpedia:
Andrew Carlssin is a fictional person from a news story hoax. A story on Yahoo reported that a man named Andrew Carlssin had been arrested for SEC violations for making 126 high-risk stock trades and being successful on every one. It was said that he started with an initial investment of $800 and made a fortune of over $350,000,000. He claimed to be a time-traveller from the year 2256. Upon making bail, he had promptly disappeared. The news article was originally published by the Weekly World News and later on was reprinted as on Yahoo News' Entertainment and Gossip section. The story was also included in the book "Pedestrian safety expert gets hit by bus" by Huw Davies.[1] It was made to be an April fools joke.

So... turns out it wasn't real, and all other similar stories I've heard have been found to be false as well.

[Bynary Fission]

Originally Posted by cry4eternity

Did a little research (wikipedia :P) and found this:


So... turns out it wasn't real, and all other similar stories I've heard have been found to be false as well.

Whoa, really? I read that out of a book called The World's Most Incredible Stories...but it was published in 1992, so it was bound to be out of date. But yeah, I figured it was something akin to a prank (And for the record, I didn't really believe he was from the future, but it was always a possibility :P).


~Bynary Fission

[ieatyourlvllol]

Supposedly, time travel essentially causes your dimension to cease to exist (relative to that which is subsequently invoked). A change of any element of the past would mean that the future would thus shift accordingly, rendering it impossible to have done so in the first place, therefore opening up a simultaneously replicating and self-terminating paradox.

Here's a rather rudimentary example that helps in visualization of one aspect of the causality paradox:

It is year 2100. You are in Dimension 1. It exists in State A.

Whilst in Dimension 1, you decide to travel into the past. Your action manifests itself in self-sustaining affectations of other events.

When 2100 dawns, it is now Dimension 2, which exists in state B, as dictated by the aforementioned action.

But wait...you were in Dimension 1 when choosing to change history. If the universe now exists within State B, the decision made within State A would have been bound to cessation, but due to the current precedence of State B, it consequently -must- have occurred.

By this notion, Dimension 1 and State A therefore must not exist. The universe as we know and experience it must then be Dimension 2 and State B, the ultimate product of all changes made to the history relative to it (and not to the other branches of existence). When you go back in time, you are in Dimension 2 / State B at first, and all changes are made to a realm (Dimension 1 / State A) that is completely removed from the parallel from which it stems but leads inevitably back to the initial reality.

I think that's -sorta- what devonin was getting at.

And while we're at it...here's another interesting concept...

Let's say you're the inventor of (the means of) time travel. Without you, it would have never been brought to humankind. Then, at some point in time, someone decides that time travel isn't meant to be toyed with, so they go back to the past for one last time and do away with you before you are to make time travel possible. But...with it gone, that could not happen. So in that case, being responsible for time travel would make you immune to assassination via that method. : O

Anyways, as for an opinion...I'm really not sure. Modern physics draws out an ambivalent stance, and until we reach that point where a tangible demonstration is brought before us, time travel exists in only theory, though who knows? It -could- be happening this very instant, and we wouldn't even know it.

[ballaw hare]

Originally Posted by ieatyourlvllol

Let's say you're the inventor of (the means of) time travel. Without you, it would have never been brought to humankind. Then, at some point in time, someone decides that time travel isn't meant to be toyed with, so they go back to the past for one last time and do away with you before you are to make time travel possible. But...with it gone, that could not happen. So in that case, being responsible for time travel would make you immune to assassination via that method. : O

Not really, it just creates an information paradox, information from nowhere. Just because you go back and kill someone who made the time machine doesn't mean the info is lost, or the machine suddenly vanishes, the laws of [macro]physics still apply.

[ieatyourlvllol]

True, but according to fundamental physics, information still needs a medium of conveyance. If you take away the medium, although the information still exists per se, it still should not be able to touch upon any form of palpable use (unless, that is, it were to somehow break free into metaphysical exception - e.g. defy the chains of paradoxical status).

[devonin]

I stated that you aren't necessarily going to fail. Read my post again, I explained why.

You failed. Unequivocably. There's no way you could not fail, because the state of reality reflects your having failed. There's no way out of that.

Not really, it just creates an information paradox, information from nowhere. Just because you go back and kill someone who made the time machine doesn't mean the info is lost, or the machine suddenly vanishes, the laws of [macro]physics still apply.

An example of the ridiculous nature of inventorless invention can be seen in Star Trek IV, the one where they go back in time to save the whales. In order to make a tank that can carry the whales, Scotty needs to show an engineer how to make transparent aluminum. When Bones tells him that by telling him how to make transparent aluminum, he's changed the timeline, Scotty replies "Well, how do you know he didn't invent the stuff?"

The implication is that the inventor was this man, and he invented it because Scotty told him how to make it.

But here's the thing: The man invented it because Scotty knew how to make it. Scotty knew how to make it by learning from a book, presumably originating with this man. The man learned from Scotty, Scotty learned from the man, but at no point in the process did anybody actually -invent- transparent aluminum. They've created knowledge from void.

[MixMasterLar]

If what Dev is saying is correct, then is it not possible tha the timeline was changed billions of billions of times and then as the earth ended one time line was locked as "The" timeline; The one that we are living in now.

Therefore, should Time Travel ever be possible, I suggest that this timeline is the timline made before the end of time itself. Which is pretty much what Dev said, but maybe putting it that way makes it easier to understand

[ieatyourlvllol]

^Pretty much

Originally Posted by devonin

The man learned from Scotty, Scotty learned from the man, but at no point in the process did anybody actually -invent- transparent aluminum. They've created knowledge from void.

Though since past invariably precedes present, the man could be said to have been (on the timeline) the prior possessor of the knowledge. Unfortunately, because that characteristic is a product of time-based influence, the information paradox that results ultimately leads into a question akin to the classic "chicken or egg?"

So it's quite possible that a great deal of the knowledge that mankind has already garnered was brought to us by future parties, though one might find it strange that there really never is much historical mention of outsiders (obviously not of the time) who just spontaneously introduced new information. Still, that might simply be due to careful monitoring of changes carried in such a way that the possibility of time travel is never brought into clearer view. And according to the causality paradox, if time travel really can be achieved, there has to have indeed been regulation of some sort.

[devonin]

In fact it seems to me that it is an absolute necessity to conclude that if time travel is invented at some point, that at some point further up the timeline, a regulatory force would have been created. It is pretty much the only way to reconcile our continued existance with the concept of time travel.

Once it can happen, it can happen at all future points, and it seems inevitable that a suitably enlightened culture would eventually develop to manage the effects of previous tampering with the timeline.

[Shenlon]

Enter the simpleton.

So I'm a failure at math. My concept of physics starts with p and ends with s. I'm dimly aware of gravity and only as a mysterious blockade to my fantasies. You get the picture.

The way I see it (which, other than being unqualified - though that case can be argued for all of our posts... we'll say I'm <i> more </i> unqualified than the rest of you, may ignore certain truths that scientists have long established to govern our world) time travel may or may not be possible. Theoretically, sure, physically? We'll only ever find out if it's developed in our lifetimes.

Give me a minute while I try to remember the original post because reading what everyone had to say gave me quite the headache. Alright, I can't...so I'll go with my gut instinct.

If we’ve established that time travel can only be possible from the point of creation of a time traveling machine onwards, I think the nature of reality would change, regardless of how it is used or for what purposes, if ever. I don’t know why I think this, I just do.

Anyways.

Like many of you have said, if someone goes back in time to change anything, no one will notice because our history will never have changed. A person can only perceive what is happening. They can anticipate the future and study the past, sure - but that’s another topic. If what has happened changed all of a sudden, they cannot perceive the change because they were simply not there. Say Hitler won the war. And we were living in blimps. And the world was a utopia. And we were all golden haired, blue eyed super-humans. It’s not like we’d know about this OTHER life we once had. That is our history, that is our life. Plain and simple.

Say you go back to save your friend bob. I’m inclined to agree with devonin on pretty much everything he has said because it makes the most sense to me. You can’t. How could you? If you did you would never know he was in danger in the first place. Unless of course a) by doing so you have nullified your current existence of knowing he had died, thereby ending everything about you while another copy of you exists in place. A copy that is none the wiser your buddy bob had ever been in danger. 

Or maybe you succeed, but then I think the world you would go back to would be the same. Any actions you may have caused in the past will start a tangent timeline. Alternate universes - sure, whatever you’d like to call ‘em. Therefore in your own timeline bob, clearly your best friend ever, would still be dead. The way I see it a cause cannot also be the effect. I know there are exceptions to this but if I went back to kill my grandfather, of course I’d cease to exist. But not because I killed him, but because I cannot exist in the new world I have created for reasons i’ve already mentioned. Or I go back to my own world where he was still my grandfather and in an alternate world I will have never existed. (Like that does me any good.)

Now I think to take that to the extreme time travel may be possible but not /possible/ unless in a purely observational capacity. Why? Because the moment you are in the past you are changing it. It may write you out instantaneously or nothing you do will have an affect on your own timeline. The only way around that would be if you could be in a sort of ‘limbo’ but I don’t know the physics of that being possible.

As for the future... well gosh darnit you guys are the experts and everything I say may in fact be thoroughly debunked. In that case, I hate all of you. If not, maybe if we get to talking about the future I’ll come up with some ideas of my (mathematically-challenged) own.

[devonin]

The idea that time travel would necessarily involve moving both through linear time and non-linearly into an alternate universe is generally one of the "easy way out" explanations of time travel. Quantum mechanics in the Copenhagen Interpretation denies that such a thing could be possible, but MWI the Many Worlds Interpretation is one of the farily well regarded alternatives.

I'm generally apt to go with the MWI myself, all things being equal, because I both find the idea fascinating and it actually creates a form of determinism that I find really intriguing to think about.

I mean, most of what I've said here has just been a philosophical attempt to remove the casuality paradox being described by others, but as has been noted, we have no real way to predict what the actual consequences of time travel might be.

[Shenlon]

Alas, the problem with thought experiments embedded in grandeur.

[devonin]

Embedded in grandeur? Mind explaining that one a little bit?

[Shenlon]

That was me being a little tongue-in-cheek. I guess what I meant was a high-concept discussion easy to discuss but impossible to reach any strong conclusion towards.

Hope that settles it.

[tsugomaru]

It is my belief time travel to the past is impossible because by doing so, you are bringing yourself back to a spot in time and by just being there, you would have changed the "past", making it your present. However, time travel to the future might be possible, although returning back to the "present" would be difficult. Why? My view on time travel is moving every single atom in the area where you want to "reverse" time back to where it used to be or will be.

I don't think we can time travel like we do in the movies.

~Tsugomaru

[ballaw hare]

Originally Posted by tsugomaru

It is my belief time travel to the past is impossible because by doing so, you are bringing yourself back to a spot in time and by just being there, you would have changed the "past", making it your present. However, time travel to the future might be possible, although returning back to the "present" would be difficult. Why? My view on time travel is moving every single atom in the area where you want to "reverse" time back to where it used to be or will be.

I don't think we can time travel like we do in the movies.

~Tsugomaru

Ya I agree, rewinding all the atoms in the universe would be pretty difficult, especially the ones that went into black holes or just disappeared completely like matter sometimes does. This is the point I get confused on the most, a lot of physicists say that time might be the 4th dimension, but that makes it so abstract. Isn't time just movement? If nothing moved would time still pass?

[devonin]

I'd argue that time is a linear dimension just as length, width and depth are.

If you imagine a three-dimensional object, it has a measurable length, width and depth, and also extends physically backwards through time to the moment of its creation.

What you'd get is a long chain object like &&&&&&&&&&&&&& representing it's entire time existing. What we percive of an object is it's length, width, depth, and a slice of it's time at the moment we observe it.

[Bynary Fission]

Time is logically, the fourth dimension, and whether you view it as spatial or not is up to your perception of time.

When you move across the first dimension, you move in one direction. In the second dimension, you move across two (length and width). In the third dimension, you move across depth, width, and length. In the fourth dimension, you move through width, length, depth, and time. When you move, time passes. You are passing through time. Therefore, it is logically a dimension, and it can be seen as spatial or non spatial (spatial being that it encompasses everything, and you move through it no matter what), or non spatial (It's not like depth, length, or width, but you still traverse through it). Maybe time does not have tangible dimensions...or does it? Mathematics were not meant to encompass time. Perhaps it can be adapted to find the coordinates of time.

~Bynary Fission