h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I haven't done much relativity in a couple of years, but my spots on this are :

You can't allelerate anything past the speed of light

Wormholes are theortical, even if we could creat one, harnessing a stable one would be near difficult. Harnissing a stable macroscale and accellerating one end faster than light, yikes!

Besides, what happens if you walk though, find youself standing in the middle of the road you grew up in, tunr around see a car swerve to avoid the current you (from the relative future) and runs you (young you, the current one in the timeframe) over. Then what happens? Paradox, time colloapses in on itself, the universe ceases to be, or to ever have been, just because somebody didn't learn their temperal Green Cross code.

I've seen it happen before, this is a warning to you, it is not worth it ...

Time paradox.. I've always thought of it this way. Anything that has happened already has happened. In other words, if I go back in time, I won't have changed anything. Any change I might make while I'm there will have been made already, as evidenced by the fact that it lead up to my current time (defining current, of course, as that time I was in before I theoretically went back in time). You dig?

Also, wormholes aren't theoretical. The possibility that they can be made stable and enlarged, however, is. Wormholes have been proven (somehow or other) to exist in subatomic form, at least according to my sources (Okay, okay, so I watch PBS sometimes when my mom tells me to get offline).
I'll have to look into it.. In the interim, any contribution you might make would rather be appreciated.

Oh yeah, and the reason you can't accelerate past the speed of light is that your mass multiplies itself until it becomes infinite. Time, also, comes to a standstill at c (e=mc^2). You can accelerate something with the mass of light or less to past the speed of light (light has been, in fact, accelerated past 186,000 mps in underwater conditions and prob'ly other conditions, too, that I don't know). So, theoretically, a wormhole could be pushed to this extent. I'm not sure about the complications with time, though, as it's the basis for my entire proposal -- the time would slow down so much that it would go in reverse. If time stops when it simply fails to go forwards, the whole idea collapses anyway. Suggestions, anyone..?

Oh yeah -- one thing I forgot to mention. How could you have seen it before? Were you there when the universe killed itself and was instantly replaced that made even less sense? Assuming this has already happened.

Seeya around.
-Temporarily cynical but still Euphoric

With regards to the time paradox, the big problem is sex (as usual). The argument going - could it be possible to go back in time and have sex with your mother to give birth to yourself?

That's a tricky one because the seed has to have been implanted by an entity that without that fetilization won't exist!!!

Or if you went back, say a further six months, got your mother heavily pregnant, so that she couldn't conceive yourself, thereby denying your own birth, so how did you get her pregnant in the first place???

And why would you want to have sex with your mother???

HB

Have you seen his mother ???

>>>Were you there when the universe killed itself and was instantly >>>replaced that made even less sense? Assuming this has already >>>happened.

Temperal grammer problem here. Since time ceases to be if the universe has vanished, it could not have happened before, since there is no before. The event occured (and in my own, personal timeframe it has happened) by there is no gramatical tense to describe it from a general point of view

Okay, conceivably I could not legitimately say that the universe "was" destroyed because that was in a different time .... line? But I could say that the universe that made even less sense "was" created because it "was" created at the beginning of this timeline.

As to the conceiving yourself -- have you ever seen the series Red Dwarf? There's a character, David Lister. He was found in a box under a pool table.
In later seasons you found out he made himself -- a test tube kid, no one else was even involved -- and then even put his own box under the pool table.

If we are thinking of time as a dimension, then measurement of it (forwards or backwards) should be possible, being clever enough to undertake the action is a different matter. As time was "created" when the universe was "created", all seperate "time lines" must have branched off after that point. If each separate "time line" has a seperate reality, then it is fesable that technology may develop to jump "time lines" into a new reality, but the question I can't get over is - what would cause a new "time line"? I suppose theoretically all time travel events must create a new "time line" (as basis of BTTF films etc) BUT as knowbody has (within our sphere of experience) proved a workable theory, nevermind managed such an undertaking, might we have a virginal "time line" and therefore be risking polution of an undiscovered wilderness? I mean, look at the detritus left up everest, just so a few people can say "I did that!"



So the next question I would like to pose is - Do we has the ability to act responsible enough, considering our race's past history, were time travel available to us?

HB

Simple harkings proof that travellign back in time is not possible: There is no evidence of anybody travlling back to our time.

If it will be possible, then it will be possible to come back here. They haven't, so it will not be possible to travel pack to this point in space time.

Imagine a single , simple time line.

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Fred (being clever and in our future) creates a time traveling machine and returns in time to our past. His re-entry into the time line is a brand spanking new event (for him time is still going forwards),

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altering the events at that precise moment in the time line. This creates a second reality or time line braching off the first.

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Hopefully the first time line doesn't cease to exist at the point of Fred's departure or re-entry in to the second/brached time line.

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Because we're still on the original unaffected time line we don't have proof of time travel by someone coming back in time and saying "Hi" as they're to busy working out what to do on their newly created time line.

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However, this doesn't affect our future, we might yet meet somebody who has created a new time line and be re-directed into it.

or something

HB

First matter: Hotblack Desiato's message regarding timelines. Why are there timelines? I used the word 'cause I didn't know what else to call it, but why should there be multiple layers of time? I mean, there is only (as far as we know) one space. When we blow something up, it doesn't make another spaceline without it blown up. (I might have completely missed something here. Let me know.

Second matter: Jon, I understand your logic but I don't agree. If, at some time in our future, we discover that we have learned how to time travel, that presumably would mean we could go back as well as forwards. Why would we want to, though? We'll already know more or less what happened in this recent past, and maybe we do go back further than recorder human history. Or maybe they come here under strict rules not to interfere with us (to avoid changing their time).
Just because there's no evidence doesn't mean it didn't happen, and just because it might not have happened doesn't mean it's not possible. Even if it's impossible to travel BACK to our time, maybe it's like that one solution listed in the official time travel section of h2g2 -- possible to go forwards and backwards, but impossible to go back further than the discovery of how to travel in time.


Third matter: Hotblack's second message.
I'm not entirely sure I followed that correctly, but I think I did. See my earlier question about timelines, and as for altering time -- well, see my earlier message in this debate about altering time. If you do anything that would alter anything significant, it will already have been in the timeline and you won't have altered anything.

-Euphoric

"time lines" is a term I use to graphically ilustrate the mind bendingly difficult concept of time. I am an engineer/nurse , not a scientist and do not know the full "en vogue" vocabulary. I simplify time as a linear dimention, much as x,y or z on a graph. Thereby, using the (over)simplyfied idea that on initiation of time, a single line (stream, reality, actuality etc.) was created, from which certain rare and complex events may create a new branch, time line, parallel universe etc.

In my simple mind, I can perceive the above idea. However, at the point that I refer to as branching, I start to blur! I feel that if you are below the point of branching (it happens in your future) you cannot know as the event is yet to happen. If you are at the point of branching, you cannot know, as it appears part of your present reality in which you imagine you have a modicum of control. If you are above the point of branching (it happens in your past), you cannot know because of, say, a sudden change of environment as you must already be part of one of the time lines (old or new) and whatever happen previously was just a natural course of events to yourself. If you are the time traveler, your perception of time will always be forward, therefore all events will seem a natural progression of your actions/reality.




HB

P.S. - If you ignite a certain mixture of Hydrogen and Oxygen, you alter sound, temperature, and create water, how many physical dimensions is that altering? Could that be classed as "spaceline" ???

Interesting concepts.

What I was saying was, I don't think branching is a legitimate concept. I mean, I understand that if you do something that didn't happen, it'll have to make something happen and this could happen in another "timeline" rather than changing your own. Assuming travel to the past is possible, though, I don't think it's possible to change anything; anything you would change would already have been changed, as evidenced by the fact that you're there, changing it (see earlier post).

About spaceline -- using it in the same context as timeline, no, I don't think so. A branched-off timeline is one that's a completely identical copy of another timeline until something changes, from what I understand. If you burn H2O and make water, that may be making a new chemical combination, but it's not making another copy of space (the universe) and changing it after a point. At least, that's what I think, I may be wrong.

You're an engineer? I ask out of curiousity.

Sorry, something I forgot to say in previous post.

There's a book of short stories; it's called "The Menace From Earth." It contains a goodly number of short stories, but I'm thinking of one in particular about time travel. Aye, I know science fiction doesn't convey an accurate assessment of what's possible and what's not, but the anecdote I'm about to tell is a good demonstration of my thoughts and I had to give credit.

So. A guy is sitting in his room doing something or other; we'll call this guy "Bob." After he does something or other for a while, someone behind him says something. Bob turns around, finds out the stranger calls himself Joe. Now, Joe wants Bob to leave the way Joe came in -- that is, through a time gate that was put in Bob's room. Bob argues with Joe for a while until another stranger (it's like the Grand Central Station of time!) pops in and says not to go. We'll call this anonymous new stranger #3. #3 fights with Joe and Bob; eventually Bob gets knocked through the time gate accidentally. Bob is knocked unconscious.

Y'all still with me? It gets worse. Bob wakes up to find a dictator some 20,000 years in the future who wants Bob to go back and convince someone to go through the time gate. Bob reluctantly accepts on the grounds that he gets a woman servant in reward. He goes back through a time gate, only to -- drumroll, please! -- find that he's in his room and he's been assigned to, while calling himself Joe, convince the old Bob to go forwards in time .... it takes some doing, but his target does eventually go when #3 jumps in, starts fighting, and accidentally knocks Bob through the timegate.

Y'all still with me? It gets worse. Joe (formerly Bob) goes back in time, only to find -- brace yourself -- that this dictator has been using him! Oh well. He goes back through the time gate after duking it out with the dictator and ends up in his apartment, fighting with Joe (Joe is trying to convince Bob to go through the time gate). He accidentally knocks Bob through the time gate. I'll leave the ending out in case anyone wants to read this story, which is definitely worth reading.

Now, do you people understand my theory? If not, I'd be happy to wait while you read it again and then let me explain it to you. Sorry if I got you confused.

*bump*

Now it's a tricky one, calling into reckoning the point that do I really believe in time travel. I feel that logically the story can't work, but I can't yet work out why! And I feel it's to do with relativity and supposed time travel. Let me get over the euphoria of beating SA in the third test, I'll come back to this one.



HB

About the its impossible to go back past the invention of time travel. does that imply that each civilization in the universe has its own time boundaries ? I'm perfectly willing to accept that we can travel foward in time, after all, we have. However traveling back onto your own 'timeline' should be impossible for as taken from the uncertaincy principle, any attempt to measure something will alteranother of its properties. Chaos theory also says that it any minute effect, however uninteded can have major consquecences. So even if somebody had rules about not interfering with the past, their presence itself will interfer.

I'm not in favour of the split universe/timeline theories just because of the vast amounts of alternatives there must be. Also why is it that we are assumed to be on a timeline that nobody has travelled to.

Thinking slowly about this, if "true" time travel is possible (which I doubt increasingly, but still can imagine) then I imagine the "dictator" was also Bob and possibly even the female slave (... hmmmmm?).

The story feels wrong because all the interactions are with himself (the point of the story-teller I guess). The subject matter is unfortunate to A) not recognise himself & B) on the second return, not to go further back in time than the first return and be in more control of the situation. But basically, the problem is the same as going back in time and conceiving yourself, or getting yourself run over when you were younger etc. In fact all major time travel questions, could anything be transported back in time???

Speed = Distance / Time

&

Distance = Speed * Time

Therefore

Time = Distance / Speed

Any positive number divided by a positive number will equal a positive (if minute) number.

Therefore, for time to be a negative, either distance or speed must be negative. Which is also an impossibilty.

So in my mind (which is like a box full of frogs at the moment), I become clearer that time travel (as the romantic story idea) is impossible. As the spooner says, what has happened, has happened, cannot be altered. There is still a question in my mind about relative travel (ie from the traveller's point of view at near the speed of light compared to a stationary point)



HB

Hey Jon -- we keep going back to the same point. Assuming it is possible to go back, it will certainly have an effect, but the effect will already have been made. IE, if you go back and do something important, it will already have been done then. I think you didn't follow my little story, but I'm not doing too well at explaining, so I'm going to come back later when my mom's not yelling at me to clean my room.

Hotblack -- again, I'll come back and give a more coherent response when I can, but meanwhile.. Bob was the dictator (though whether or not he's the female slave is never mentioned). This is because the ending I left out was him travelling back ten years so that he can kill the dictator and take his power once he arrives. The thing is, the dictator never arrives and Bob eventually realizes he is the dictator. You were right, then, about that.

Also, so okay, I understand that distance cannot be negative .... unless you consider relativity (no, not Einstein, just relativity). If you're looking, say, north and you go 50 feet south, haven't you gone -50 ft forwards? Maybe I'm wrong. About speed, well, if you take into thought relativity (and yes, this time it is Einstein's relativity) and the possibility of exceeding the speed of light .... your speed can be negative because you're moving forwards but backwards in time .... which implies a negative speed.

I'll come back and read this later when I'm not distracted, sorry.

Something I never actually considered before -- my first post in this thread (indeed, my first post on this page) suggested that you could send one end of a wormhole back in time and then walk through it and end up on the other side. The opposite end, which is what I never considered, is that you could accelerate yourself with one end of a wormhole, leaving the other end where it was. This is, assuming one can enlarge and maintain a wormhole, impossible to refute. Even if it's only a difference of milliseconds, you'd be going back in time when you stepped through the wormhole.

This is because time would go marginally less quickly for you and the wormhole than it would for the standstill wormhole (here again I am referring to Einstein's theory of relativity).

Okay, back to room cleaning. I'll return later for coherency.

Sorry -- let me say that again. You'd be travelling forwards in time because the standstill wormhole would be going forwards in time faster than you and your end of the wormhole would.