Time Travel - An Impossibility?

minimcmonkey

Sep 19 2008, 09:42 PM

Ok, I dont really know anything about the subject. But I just spend a lot of time thinking about this kind of thing, so thought i would post my thoughts and ideas, and see what people think.

First of all;
What do people mean by "time travel"
Now, i think most people think of traveling back or forward in time, and being in a certain place at a certain time, in full body, when they think of time travel. But is that possible?
But surely time travel could just be seing, history, or future.

And how would it work?
Surely it would involve opening time, and placing yourself, in that time. Or having a machine, push that time into your head as a vision or thought. And how much energy would this use, surely, it would take huge amounts of ebergy, to open time and space? And would it scar time? Would opening or manipultaing time itsself, destroy physics? What are the concequences?

The dangers,
Im sure nearly everyone has seen some movie, or something, where someone goes back in time, changes something, goes back to their own time and finds their tiny change, has changed the entire of earth. Would that happen?
And would effect would it have on the body?
Being pushed through time? Would the sheer shock, or energy kill a human?
And what happens when you get there? The average ancient egytian, probably wont be accustomed to seeing a 6 foot tall person, wearing a lab coat, holding a laptop under their arm (possibly not the average person bu anyway..) So, what happens? They will probably be killed. But then, what hapens next, what happens, when the aincient society, finds an electronic device hunreds of year early? Who knows?
And what happens to the body while somewhere else, is there any trace of the body in its normal part of time while visiting another time? will just a copy of the person be sent to another time, if so, what happens if/when the copy dies?

And imagine what could happen, if terrorists could use time travel. It is often almost impossible to find the hidout of a terrorist on earth, now think, what happens, when not only do you have to find where they are on earth, but also in time. Now, that terrorist can hide, or comunicate, with virtually no chance of being found. Dangerous, and time travel could mean, somepone could go somewhere, and evaluate the security, then go back again, to bomb it, or do something terrible.

But think of the advantages.
We could find out how the eart came to be, we could meet the first humans, see the first animals.
We could visit places in history we have no knowledge of.

Any opinions?

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shadowx

Sep 19 2008, 09:59 PM

well i dont want to say what will happen in the future, lets not forget Bill Gates once said 64k of RAM would be enough for anyone, and someone predicted the world would have a limited number of computers (i cant remember the number but its less than ten) They were grossly wrong...

Instead i want to tackle one of the leading theories, that travelling faster than light enables you to go back in time. I dont think this is true. the interesting thing is however, that they have done experiments with two atomic clocks, one of earth and one in a plane or satellite or something. And the one moving was actually slower than the one on the earth, indicating that as speed increases the rate of time decreases. Anyway, back the light speed theory.

I see it this way. It is true that if you were to go much faster than the speed of light and take off from Kennedy space center, you could (if going fast enough) be back in time to see yourself board the space ship. However, what would happen if you tried to touch yourself (easy there!) Because that image you are seeing isnt really you is it? Its simply the light reflected off of your body, and because you travelled much faster than that light you reflected you essentially beat the light to your observation point. (imagine the light hitting you and reflecting 10 feet backwards, but you trvalled around the world so fast you got back to that 10ft spot before the light did)

SO according to that i think you can SEE back in the future but not GO back there by going fast. Although the atomic clock experiments do challenge that theory which is something i find absolutely amazing.

As for tearing or manipulating space-time... Im not so sure. they do say if gravity is focussed enough (like a black hole) it bends space-time so much it makes a tunnel or worm hole that can go between space and time. However I cant possibly understand how nothing (the vacuum of space) can be manipulated. It just doesnt seem right.

But there are things well beyond my understanding, such as how can light be both matter (photons) and energy at the same time? Why is it if you shine one photon of light through a board with two holes you would be able to record two light beams (one for each hole)? How can that one particle split into two? And why is it that if you set up recording equipment at the board with the holes in it to record the moment the photon splits into two, the photon would NOT split and you would record only ONE beam of light, purely because you are watching, how does it know you are watching?! how?! (this is real, check it out on how stuff works, quantum physics, not sure of the exact article but it is real) Theres some weird stuff out there and the fabric of space-time is one of them.

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Posterchild

Sep 20 2008, 06:38 AM

One thing that points to it not being possible is the fact that it is not in existence.. there are no time machines or time travelers, nor is there any indication that anyone can tell what went on in the past with any absolute certainty.
One problem with time travel technology is the old paradox problem.. given that as soon as you make a working time machine capable of going back to a time before it was invented, you have the chance of someone, somewhere in the future, deciding to go back and stop the time machine ever being made.. and there is a lot of future ahead of us, a lot of chances for that to happen. Statistically, given the amount of time involved, it is almost certainly going to happen.
One could say that the fact there are time machines is proof that this has already happened.

So maybe it is possible to make one after all... we will never know for sure.

What a pity, that the very process of building a time machine, also assures that it never will be built at all.

lol

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travstatesmen

Sep 20 2008, 08:39 AM

Although, think of it this way. Maybe we are looking at the problem the wrong way around. Maybe the fact that nobody has as yet come back from the future is because we haven't yet got the technology to be able to provide a good reference point for someone in the future to come back to!

I remember as a child at primary school learning about time capsules, you know, everybody puts something into a sealed canister and it gets buried for future generations to find. My contribution to our class time capsule contained a letter to future time travelers. I was about 7 years old at the time, and I had a watch and a compass with me. I remember standing on a grassy knoll at the end of the play field on a certain day, at a certain time, facing a particular direction, and making a note of it in my letter to go into the time capsule, with a request that any time travelers meet me there. The letter was sealed and added to the other letters of my little classmates and the time capsule was duly buried by the school principal at a special ceremony. For all I know that time capsule is still buried there.

My request was never answered from the future though, as no time travelers ever came to meet me on that grassy knoll. Maybe the time capsule was/will be dug up by somebody before time travel in the future was/will be discovered. Maybe it was/will be found by somebody who didn't know about, or was/will be opposed to, the technology required for time travel. Maybe I should have done it around the other way, and given the details of a time in the future, such as the day after the time capsule was buried, when I would be standing on the grassy knoll, at 12:00pm, facing due North. Whatever the reason was/will be for the failure of my first call for aid to a time traveler from the future, imagine my interest and fascination when GPS technology was invented, some 15 years later! With this new technology I could provide a much more reliable set of facts for a future time traveler to triangulate on!

But there are so many variables involved. Take, for instance, the Dead Sea Scrolls. They have essentially traveled through time to us over the centuries, just as my letter in a time capsule was meant to be projected forward in time. But the information that they contain is hard to comprehend. Over time languages change. Over time the media that they were written on has degraded. Over time the culture and sense of the words may have changed, such that even if the words could be read and translated, the words might have a different meaning than they did back then. Taking this example into today's world of GPS technology, if such a message to the time travelers of the future were sent using computer technology as a time capsule, would anybody in the future be able to read it still? I hope that the information isn't stored using a Microsoft proprietary document format, as they have major problems with backward compatibility already! Imagine some future infotech archaeologist trying to decrypt a DVD containing a Microsoft Word document from 2008! Apart from the document format, try finding a computer today, in 2008, that can read a 5.25" floppy disk! Will they still be able to read DVD's in the future?!

These are the things that intrigue me about time travel. If we can provide a suitable landing strip for a time traveling machine, and then advertise it to the time travelers of the future, would they not be more likely to land on it? It is a very different way of looking at time travel. But I've always been a little different.

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pedro-kun

Sep 20 2008, 10:58 AM

Who would've thought that one of the most realistic solutions to this problem could be found in.... a game.

If any of you have player Serious Sam before, and at least remembers the story, it really makes some kind of sense.
To all the others who haven't played, here's the thing:

Sam "Serious" Stone is a really cool guy who comes back to the past to save the Earth :p But how he does that is what's cool. Supposedly, the Sirians (which would inhabit the Egypt back then), left a device called Time-Lock. This device created one end of the time traveling wormhole... In the far future, humankind created another time-lock and activated it, linking it to the one that had been activated in the past (creating the other end of the wormhole and linking them both - a complete wormhole).

I know this is just a game and you can't base anything off of it. But the game did take these ideas from what scientists think about time travel! They consider the possibility of us being able to travel back and forward in time, but only *after* time-traveling has been "discovered". This solves the "go back and stop the time machine from being built" paradox, but it is not the whole solution, of course... Also, the grandfather paradox remains. But this too can be "solved", if we think that time will branch for such decisions. So, you'd be able to kill your grandfather, and you wouldn't be born at all... in some other parallel universe.

Conclusion: We may be able to travel through time, but only as back as to when the time-machine itself was invented. Also, we may be able to "change" time in a way, but that wouldn't affect our universe because that would violate several laws lool. So, it would just be something like "looking back".

(oh! and if we wanted to travel even farther than when the time-machine was invented, we could always rely on the possibility that other kinds of beings (aliens) could have invented similar technologies and thus enabled a "Time-Lock" even before we did... We could use theirs, and then head towards Earth, and then violate the "stop the machine from being built" paradox :p).

I know, I know, a lot of fantasy here... But they do make some kind of sense ;)

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shadowx

Sep 20 2008, 11:18 AM

QUOTE

Maybe the fact that nobody has as yet come back from the future is because we haven't yet got the technology to be able to provide a good reference point for someone in the future to come back to!

This is the leading argument against:

QUOTE

One thing that points to it not being possible is the fact that it is not in existence.. there are no time machines or time travelers

One theory suggests that if i were to create a time machine on december 25th 2008 it would NEVER be possible to go back before that date. No matter how far in the future you were you could only ever come back to dec 25th 2008 because beyond that point the time machine you are standing in does not exist, and if it doesnt exist it cant carry you back in time right?

And as for the paradox, lets use the grandfather paradox, it is thought that the act of travelling back in time could spawn a parallel universe, or the act of killing him would cause the parallel universe to spwan. So now you are in two universes (for simplicity's sake) when you travelled through time you went into multiverse two (its not a universe if there are more than two now is it!) and kill him. So in that multiverse you no longer exist, however in multiverse one, your home multiverse, you DO exist and because of your existence in multiverse one you are able to exist in multiverse 2 in your time travel form. So when you return home you would presumably go back to multiverse one in which you never killed your grandfather and s nothing has changed.

you would of course be unaware of the changing between multiverses and you might just assume that no matter what you do in the past it never affects the future.

see How Stuff Works for a more in depth article! (no i didnt copy it from there, i read that a little while ago and saw a documentary on space-time and combined the two.

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saitunes

Sep 20 2008, 12:31 PM

I can remember reading in the newspaper that time travel was not an impossibility, the physics of how it would be possible exist, we are only limited by the amount of energy it will use (if I remember correctly) It's not as simple as Doc brown hooking up wire to the clock tower and sending lightning into the flux capacitor, I cannot remember the statistics about how much power it would require, but it was a helluvalot, I mean something like our power usage time 100. (not exact but something like that), in other words alot more than we have access to right now. It said it was definitely possible.

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pedro-kun

Sep 20 2008, 01:13 PM

QUOTE(saitunes @ Sep 20 2008, 01:31 PM)

Considering that opening a wormhole would be something like having the mass of a black-hole rip the time-space, the energy required to keep the wormhole open would be massive (it would be like trying to create a black hole on our own!). However, there's still the problem of "will it be time travel"? We don't know what awaits on the other side loool

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Posterchild

Sep 20 2008, 02:03 PM

If that is referring to the Kerr singularity and the wormhole concept attached to it, that was largely debunked by Penrose in the nineteen sixties.. but the lure of the quick fix solution keeps the dream alive I guess. The basic idea is that all stars rotate, so a collapsed star will still be rotating, and observations have confirmed this.. however, and quoting wikipedia "A rotating black hole can produce large amounts of energy at the expense of its rotational energy. In that case a rotating black hole gradually reduces to a Schwarzschild black hole, the minimum configuration from which no further energy can be extracted.". So even if the singularity was spinning fast enough to create a ring, it would not last for a great deal of time.
Second problem, and a major one, is that any matter passing through the event horizon and getting anywhere near the singularity is going to get severely messed up by tidal forces.. in astrophysics, they call this "spaghettification" (thanks to Stephen Hawking)... no object in the universe is strong enough to withstand this, it is just going to get destroyed, really, really badly.
The idea of passing a living human through a wormhole... honestly, thats like throwing a frog in a blender and expecting it to come out in France, in 1783, perched on top of a hot air balloon... its just not going to happen.

How to travel back in time?
What is time?
If time is expressed as the change of states, then we could stop time by stopping all energy interactions in the universe.. if absolutely nothing changes, then what sense does time make? A photon doesn't experience time, because it doesn't change.. from the perspective of a photon, traveling from a distant star, it is created, then suddenly it is hitting your retina and interacting with an atom in your eye.. for it, there was no distance or time involved, it simply didn't experience any change at all... thats why, when you look up at the stars at night, you are looking back in time, to how they were when the light hitting your eye was first created.
So particles traveling at light speed do not experience time.. well, what if we could somehow detect or calculate, with absolute accuracy, where every particle in the universe was, at any time in the past, and had a machine so incredibly powerful, that it could move every particle in the universe, back to where they were at any time in the past.

A machine with enough energy to tear the universe apart and put it back together again, in a precise fashion...

Yeah I don't think that would be a very good idea.

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freeflashclocks

Sep 20 2008, 03:16 PM

I guess i made it all back to 2/2/2 in the poll, i voted no way we can not go back and change, mainly because i do not beleave we can go back to the past and change whatever we did back then, that is insane, i guess you are seeing too many movies and television, which are not only influencing you but many more people world wide, and i realy hate that.

Time travel is not possible according to many laws but, if that was possible, lets just imagine if that was possible, would i want to go back to my past and change something in it?

I do not think so, i do not regret one litle thing that i did in all my life, not regreting is part of my life philosophy, of my strenght, of my inner strenght , so i would not go back for anything in the world, not for me, unless, except one thing, which is not because of me or for me.

The only exception that would made me think if i could go to the past and change is if i could save a life of someone that i love, that was the main and only reason.

Even that same reason would make me think twice because time travel, if possible, could be dangerous, i could affecting the person that i love, myself, and others, i could be killing many people without knowing, that is the main dangrouns and the main risk of messing with the past.

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rpgsearcherz

Apr 15 2009, 01:11 AM

QUOTE (rogerthecamel @ Apr 14 2009, 05:44 AM)

The problem with alternate dimension theories is that it requires that every single choice or possible difference cause an alternate reality to be created. That means at every single moment of every single day billions of new realities would be created by the billions of people on earth. To traverse such a dimension would be impossible because each branch is a new direction to travel. Also decisions aren't binary. in other words each decision you make isn't a 'yes' 'no' choice, all the choices in between the extreme choices that could be made are possible.

The other problem with this theory is questionable choice. Lets say you are angry with someone you know. One choice is to let it go, and ignore it. Another is to get pissed off and yell at them. Well in this theory all possible decisions play out in alternate realities. But I would never choose to kill the person, but thats a possible choice that could be made. Just like I might yell at them, it all depends on what previously happened in the day and so on. In this way I don't think that multiple alternate realities exist. They don't really make a lot of sense.

Exactly. What you bring up is kind of like the movies Butterfly Effect and Butterfly Effect 3(I don't remember the second one very well).

In case you haven't seen it, it's about a guy who can go back into the past to see things that happened and can change his actions to have effects on the future. He could go back and say something different for example, and wake up in a completely different life than he was in before.

Things like this are entertaining to watch but to think there's even a remote possibility it could happen is too far off in fantasy land. I think a lot of people wish it was true so they could fix things they did wrong but if you think about it, what you did wrong put you where you are today. Every mistake you make teaches you something new. In the movie, for example, every time the main character(there's two...different ones in each movie) changes an action he did from bad to good it causes negative effects to not only himself but those around him.

The movie teaches the view that you should "leave the past behind." Or "keep moving on and don't look back." Those who keep wanting to re-do things they've done already have no idea what kind of consequences would occur due to having made said choices.

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rogerthecamel

Apr 14 2009, 10:44 AM

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handywork

Apr 14 2009, 07:06 AM

When the current Doctor Who 'regenerates' the next one will be played by a 28 year old actor. The first Doctor Who had a grand-daughter with him. So when the new one appears next year it would make an interesting story to have the two meet again. The grand-daughter of the 28 year old will be 69 years old.

So is the grand-daughter a Time Lady or not?

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ORene

Apr 14 2009, 06:30 AM

In my opinion, time traveling is impossible. However, I think dimension traveling will be achieved one day, which would allow us to fix things in different dimensions. Parallel worlds where the things have happened, are happening or haven't happened yet. Yet another theory I've read about is that energy beings are not affected by time therefore if we managed to transform into an energy being and get "affected and unaffected" by time AT WILL, it could then be possible.

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rogerthecamel

Apr 8 2009, 06:28 AM

Ok, where do I start.
First I guess that time is the 4th dimension. I think in general this is true but not quite as most people understand it. The idea of time and history as a simple dimension similar to length, width and height doesn't really make much sense. If this were the case then we could find some way to move along it (aka time travel). The big problem with motion through this dimension is that you are already occupying it. If I were to give myself momentum in the negative direction of time I would run into myself instantly. If we imagine what our bodies would look like if we took this dimension into account then we would be long snakes that occupy every moment along the dimension. Because of this fact I do not think history and future are really part of the dimension of time.

More likely is that the dimension of time is almost like a rate of change dimension that causes the basic laws of physics to vary in strength. Take an atomic clock, it has been proven that they run faster in space than they do on the earth. This is because of the distortion gravity has on all dimensions including time. We may say time has been slowed but really what has been slowed is the break down of the caesium particle. I would also imagine the speed of electrons orbiting particles has been slowed, electricity would run slower, our brains react slower, basically everything. If we were to extend this effect to the extreme and pass the point of zero motion then we would get inverted motion and inverted effects, effectively running things in reverse. But this would only be localised and as the system is unlikely to be identical as it was when created the past that is moved into will unlikely be the same.

Take for example your want to travel back in time, you decide the best way is to run the entirety of the universe in a reverse direction. First you would have to be outside of this reversal otherwise you would be taken along with it, forget everything and probably leave the universe reversing forever. So you sit outside the universe and watch it start to reverse, then things start going wrong, things that happened before when you were part of the universe now would not have happened, basically the universe would be rewinding as though you were never there, but it still ended up in exactly the same place, this would be some kind of paradox because your friends and family would know of your existence but no one would have ever seen you or ever have been effected by you.

Ok, so sometimes seeing time as a dimension is a little boring because it doesn't really fit as a normal dimension as simple as space. Lets imagine that time travel is possible, you can go back in time and exist in the past. Can you change it. Here are my two thoughts on this:

1- No, basically what has happened always happened, you travelled into the past and killed your granddad by mistake? Guess what, it wasn't really your granddad, he had his sperm frozen, or you are medically insane and had always just imagined your grandfather when you grew up. Basically with this notion is there is one time line and you cant change it, not without messing with your head. There are some interesting things you can do though. "What you don't know can't hurt you" - if I travelled back to medieval england and killed king arthur well some would say I have changed history, except that I don't know how king arthur died, so therefore what I did could have always been the case. The invention paradox is still possible - if I travel into the future, find a cool device and take it back without finding out who invented it, then I am free to invent it.

2- The other most widely notion changing the past is that it creates alternate realities/universes. Well firstly I highly doubt the act of travelling back in time has a side effect of duplicating the universe unless it is a phenomenon that is reasonably common. It would also mean that in travelling back to the present there would either be a duplicate you because the change would mean it was unlikely you travelled back at the exact same time if at all, or you wouldn't exist at all, and if you went back far enough then no one you ever knew would exist either. One of the theories that supports the multiverse is that a new universe is created at every decision point you ever made. But since thoughts are related to collisions of particles and how they interact using quantum physics to determine what could possibly happen then at every collision of every particle an infinite number of new universes are spawned to create every possibility. This seems way to big to be possible as the multiverse would exponentially grow in its already infinity.

This probably turned out to be very long, but id also like to quickly add that time doesn't stop at the event horizon of a black hole. The event horizon is the point outside a black hole where nothing can possibly escape. At this point not even light can escape the extreme gravity. The point where time stops I think is actually at the singularity itself.

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Time Travel - An Impossibility? - Is time travel possible? Will we ever manage it? What are the dangers?

Time Travel - An Impossibility? - Is time travel possible? Will we ever manage it? What are the dangers?

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