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Shivan
April 9th, 2005, 06:02 PM
Many theories exist on the subject of Time Travel and whether or not it is feasible/possible. There are some who are fanatical while others are skeptical.

And more than likely the majority of us either a) Never care enough to give it deep enough thought or b) Believe it to be unfathomable and impossible.

I've been in many discussions on this matter, and I'll be honest I do not know much about it. But this seems like a good place to start a healthy discussion for it.

I'll start off with a basic question/statement to get this thread off the ground.

--

Many argue that time travel isn't possible for the sole reason that time isn't a force which actually exists. Unlike gravity, time is just something we humans keep up with by assigning hours to the days and days to the week.

Universally speaking, time may not even exist. There may not be a beginning nor an end.

--

Discuss!

Matt G
April 10th, 2005, 10:21 AM
I'd respond to that with the theory(not sure who to give credit to but I know the basics) that Matt G's bedroom in Teddington, Greater London UK 7pm 8th April 2005 is a different location to Matt G's bedroom in Teddington 6:59pm 8th April 2005 and Matt G's bedroom in Teddington 7:01pm 8th April 2005.

Therefore, time travel just involves travelling between locations that are extra hard to get at.

Assuming that, I also think that travelling back in time is like playing a computer game. Let's say I travel back to Teddington on a Sunday evening in Aprill 1995. Everyone who 'belongs' in April 1995 is preprogrammed to behave in a particular way on that particular evening by Time. My presence there on it's own won't change anyone who belongs in April 1995's Sunday evening. They'll just be watching the Antiques Roadshow, eating dinner, walking down the street, chilling out...whatever.

Once they've lived that day once, without a time machine, they can't do anything about it.

However if you shoot a bad guy in a computer game and he dies, he's no longer in your way. The scenario has changed.

If I decided while in April 1995 that I fancied a pizza and I'd brought enough cash back with me, then OK, I find find myself a pizza place in the area of Teddington April 1995(even if I had to get a bus to Kingston to eat at the Pizza Hut there). However in doing so I'd change the scenario in various ways.

There would either be less space on the bus to Kingston or someone would have to wait longer on the bus than they had done previously.

Someone might get turned away from Pizza Hut because I'm taking up a table which they'd have taken up previously.

And the Pizza Hut would have had to order up a fresh batch of pizza bases, sauce, cheese and pepperoni slightly sooner than they'd have done previously.

Shooting the bad guy won't neccersarily end the game, but it changes the scenario.

2005 me getting a bus to Kingston and visiting Pizza Hut for a pepperoni pizza in April 1995 won't end the world(unless one of the people affected got really annoyed and decided to blow up the world!)

Anubis69
April 10th, 2005, 10:38 AM
Can't remember where, but i remember reading that if travelling faster than the speed of light is possible then going back in time also is. Can't remember the specifics either, but since i hope, and believe, that we can go faster than light i'll assume it's true!!

The way i see it, is there's two kinds of time travel. That everything is meant to happen, going back in time is included in that, like in the season 2 episode "1969" where SG-1 went back in time and hammond helped them, then when they got back they realised that hammond knew all along. An interesting point and brings in the idea that everything happens for a reason etc etc.

The second is that time is linear and that if someone goes back they alter life as they know it. obvious examples include back to the future and where i think SG-1 contradicted themselves on it, "mobius", "2010" and "2001". Also my understanding is that Star Trek works the same way as this.

Supreme Commander Gav
April 11th, 2005, 01:59 PM
My first post, so go easy! I'll add my two 'cents' to 'coin' a phrase. Heh.

Anyway, Lets look at a number of facts:

1) It is shown the faster you are the more time slows down.

Yes it 'slows down' but at what point does it turn backwards on itself? Some people say if we go faster than the speed of light. Personally I believe this wouldn't reverse anything it would bring time to a complete standstill or I could be wrong - Probably am.

2) Multiple Universes.

I can appreciate that if there are multiple dimensions out there then it may be possible to travel to another one of these, but I have no doubt that you could never travel back to your own dimension because then we start getting the grandfather paradox and I don't think we want to go there!

Matt G, refering to your post I believe that if you were in your own universe then doing what you suggested could be disastourous for your self. Say someone in your pizza hut got pissed cause they'd made one to many pepperoni pizza's and you get mugged. This is just an obscure example mind you, this Could lead to a series of events in your life which would never take you through the time machine and then we start getting into time paradoxes again

Anubis, I can see the reasoning behind your two choices of different time travel, obviously they inter connect with each other, I can't help wondering the following though. Why did SG-1 have to go back in time anyway? Technically its all in the past and everything has allready been done with either means that every single dimension in the entire universe would have to go back in time, and what happens if one fails? Then were pretty buggered!

As I stated before I believe time travel one day will be possible in one direction only - the future - by slowing down time relative to the undertakee, hope I've provided some in sight too my way of thought :)

Matt G
April 11th, 2005, 02:47 PM
If the 2005 version of me got mugged in 1995 then it wouldn't affect my personal history up till 2005. If someone in the Pizza Hut in '95 got pissed off because he wasn't able to get a seat or something and through their anger bumped into my 1995 self a few days later and mugged him then yes my personal history would get affected but it shouldn't affect my journey back through time. If the guy killed my 1995 self...then we'd be talking paradoxes yeah.

But unless that or some other event happens that prevents the possibility of me travelling back from 2005 to 1995 there would be no paradox.

Shivan
April 11th, 2005, 03:19 PM
My first post, so go easy! I'll add my two 'cents' to 'coin' a phrase. Heh.

Anyway, Lets look at a number of facts:

1) It is shown the faster you are the more time slows down.

Yes it 'slows down' but at what point does it turn backwards on itself? Some people say if we go faster than the speed of light. Personally I believe this wouldn't reverse anything it would bring time to a complete standstill or I could be wrong - Probably am.



I do not think that traveling faster than the speed of light slows down time at all. You're just moving fast and can cover less space in a smaller amount of time.

Supreme Thor
April 11th, 2005, 04:38 PM
If the 2005 version of me got mugged in 1995 then it wouldn't affect my personal history up till 2005. If someone in the Pizza Hut in '95 got pissed off because he wasn't able to get a seat or something and through their anger bumped into my 1995 self a few days later and mugged him then yes my personal history would get affected but it shouldn't affect my journey back through time. If the guy killed my 1995 self...then we'd be talking paradoxes yeah.

But unless that or some other event happens that prevents the possibility of me travelling back from 2005 to 1995 there would be no paradox.


Actually, Matt, there have been stories about the theories of time travel (ex: "The Sound of Thunder", a short story). The theory in most of these stories (and, I believe, including "Moebius") is that the smallest change in the past, due to the forbidden presence of a time traveler, can change the course of the entire future. I mean, look what happened with SG-1: all they did was try and steal a ZPM, a simple task, right? Well, that simple task ended up in the deaths of more than half of SG-1, and the total alteration of the course of the future.

So, my belief:

I don't really believe time travel is possible at our current level of technology. I think at some point, somebody with the right idea will achieve it. But, even if we do manage to somehow achieve time travel, I think it's a science that man was not meant to mess with.

Shivan
April 11th, 2005, 04:58 PM
Actually, Matt, there have been stories about the theories of time travel (ex: "The Sound of Thunder", a short story). The theory in most of these stories (and, I believe, including "Moebius") is that the smallest change in the past, due to the forbidden presence of a time traveler, can change the course of the entire future. I mean, look what happened with SG-1: all they did was try and steal a ZPM, a simple task, right? Well, that simple task ended up in the deaths of more than half of SG-1, and the total alteration of the course of the future.

So, my belief:

I don't really believe time travel is possible at our current level of technology. I think at some point, somebody with the right idea will achieve it. But, even if we do manage to somehow achieve time travel, I think it's a science that man was not meant to mess with.

I have a few things I'd like to say-

If Time Travel isn't possible, but alternate universes DO exist and we find a way to travel between these realities than essentially we can find realities that are slightly different compared to when the Universe began. A good example of this is in the Sliders episode. It's not really going into the past, it's going into an alternate realm where the present time is the past compared to our realm.

^I don't know if that makes any sense or not, lol.

But anyways, we wouldn't be changing much there because the future still isn't certain and hasn't already happened. Though if we achieve Time Travel then just the act of using the machine to go back and time is dangerous. Especially if someone saw it. The slightest difference CAN change the whole future.

TechnoWraith
April 11th, 2005, 05:04 PM
Well, according to Einstein's Theory of Relativity, the faster you go, the slower time moves. (I think that's it).

So theoretically, if you travel fast enough, you'll bring time to a stand still. So if you travel even faster than the speed required to bring time to a standstill, will time start going backwards? Then again, if you're moving so fast that time stands still, there's no way to tell how fast you're going (because you're measuring distance over time, and since time is stopped, you won't know).

Strange as it sounds, it's a thought that came into my head while reading this thread. :)

Shivan
April 11th, 2005, 05:21 PM
Well, according to Einstein's Theory of Relativity, the faster you go, the slower time moves. (I think that's it).

So theoretically, if you travel fast enough, you'll bring time to a stand still. So if you travel even faster than the speed required to bring time to a standstill, will time start going backwards? Then again, if you're moving so fast that time stands still, there's no way to tell how fast you're going (because you're measuring distance over time, and since time is stopped, you won't know).

Strange as it sounds, it's a thought that came into my head while reading this thread. :)

I understand what is being said here. Think of it kind of like when Superman is running faster than the speed of light, he is going so fast that everything around him is going slow from his perspective. My question is, does our brain have the ability to process what we would see if WE were traveling at that speed.

I think time doesn't slow down, it just looks like it because you're moving over more distance much much quicker.

Jarnin
April 11th, 2005, 07:49 PM
Since this is the science and technology section of the forums, I figured I'd provide some links to information which is related to this topic:

Time travel (http://en.wikipedia.org/wiki/Time_machine)
Types of time travel (http://en.wikipedia.org/wiki/Time_machine#Types_of_time_travel)

Einstein's theory of relativity (http://en.wikipedia.org/wiki/Relativity_theory)
Time dilation (http://en.wikipedia.org/wiki/Time_dilation)
Wormholes (http://en.wikipedia.org/wiki/Wormhole)

When it comes to what types of time travel I think nature allows, I'd have to go with:

The time line is consistent and can never be changed.
Any event that appears to have changed a time line has instead created a new one.
With those guidelines, anybody that travels back to the past automatically creates an alternate timeline where they can do whatever they want without changing anything from their 'home timeline'.
I could travel back to the past, accidentally kill my grandfather before he fathered my father. My grandfather, and my father would still exist in my home timeline.
This set of rules would explain why there hasn't been any evidence from the future in the real world. Since time machines don't exist yet in our current timeline, that would mean it's either impossible to build one, or they don't end up here when they travel back in time.

The only drawback to this set of rules is that once you travel back in time, you can never travel back to your home time line. You'd basically be stuck in alternate timelines for the rest of your life. You'd cease to exist one day in your home timeline, never to be seen again.

lionel_pendergast_rocks
April 11th, 2005, 08:00 PM
i find that time travel is a very fascinating subject, and it's really confusing at times. for instance, while watching moebius, i was sitting there, trying to piece together all the events and see how they fit together. but even in its coolness, i don't really think it will ever be possible. it's an amazing subject, and i'm glad someone started a thread about it. but hey, it's cool in stargate, so i'm good with that.

Bacardi
April 12th, 2005, 05:58 AM
my opinion of time travel, directly linked to what we see on sg1 and atlantis, is that if time exists, and is effectively on a line ("timeline"), if it were possible to travel back along the timeline it would create a branch parallel to the previous timeline, so rather than being able to go back and change something, it would be like making a copy of time and deleting everything back to the point at which you travel. my opinion would be that one could not travel back and forth in one's own timeline as each trip in time would create alternate timelines.

Anubis69
April 12th, 2005, 11:19 AM
The time line is consistent and can never be changed. Any event that appears to have changed a time line has instead created a new one.
yeah, i like that!!! it's a bit like that episode of charmed where cole turns back time to stop the charmed ones meeting paige, whether he created an alternate universe or actually altered time, i can't remember but it is similar.

Oh yeah, and Shivan, thanks for starting this thread! after posting in it the other night, i brought it up when i was talking to some friends. it got us debating for ages!

One point that did come up, one guy said that if we went back in time, just being there would alter it, which i disagree with. i'd say the traveller would have to interact with the surroundings or someone (eg. like picking a flower and preventing someone from picking this flower later in life and hence someone not receiving it and a relationship failing), and not just being there. his reply was....."you could be corroding the ground by standing on it"!! even in an extreme case i could understand standing on grass, but i don't think one other person standing on concrete changing the whole history.

Shivan
April 12th, 2005, 12:11 PM
yeah, i like that!!! it's a bit like that episode of charmed where cole turns back time to stop the charmed ones meeting paige, whether he created an alternate universe or actually altered time, i can't remember but it is similar.

Oh yeah, and Shivan, thanks for starting this thread! after posting in it the other night, i brought it up when i was talking to some friends. it got us debating for ages!

One point that did come up, one guy said that if we went back in time, just being there would alter it, which i disagree with. i'd say the traveller would have to interact with the surroundings or someone (eg. like picking a flower and preventing someone from picking this flower later in life and hence someone not receiving it and a relationship failing), and not just being there. his reply was....."you could be corroding the ground by standing on it"!! even in an extreme case i could understand standing on grass, but i don't think one other person standing on concrete changing the whole history.

Well if you even want to be more technical doing absolutely nothing but being there could also change the timeline thereotically. Mainly because someone could glance your way and study you for two-three seconds and that changes their whole life, which would cause a MAJOR change in history. Just being there changes everything, because you were never there to look at before.

I am fond of the theory in which when you go into the past timeline you create a new timeline instead, but your timeline still exists. But the person above said you couldn't ever get back to your own timeline, I do not see why you couldn't? You never did anything to change your timeline, because this theory prevents that by creating the new timeline. Say your friend saw you get in the machine and POOF be gone. Nothing has changed for your friend, and you are still gone and missing. You could come back a day later and explain what happened on your trip.

I don't know really, I want to know what would really happen if we did ever achieve the possibility to travel through time.

_Owen_
April 12th, 2005, 12:49 PM
ok i havent read all of the posts here, but i will try to clear a few things up. first of all by our scientific understanding you can not travel faster than the speed of light. now lets say for the fact of argument that you can. now there are two types of movement, there is the regular linear movement that we know and realize that we use everyday (walking, traveling by car, etc.) and then there is movement in terms of time, ther faster you move linearly the faster you move in terms of time, lets call linear movement ML and lets call movement in terms of time MT, now even the smallest ML will move you faster than normal in MT. in the universe the MT is predetermined, if you are in space, completly stationary, the MT will be moving at a normal rate, if you are wearing a jetpack and blast forward at 1 mph, your MT will be moving faster than normal, it will be an incomprehensable amount of time that you move forward. say that your entire life you move at 800 mph, you will live a shorter time than if you moved at 1 mph your entire life. the amount of time that you would live if you were moving at 1mph is almost instantaneous, you would not even be able to tell the diffrence seeing as the period of time is so short, in our terms of recognization of time. Time Travel is an incredibly complex subject and for me to type everything about it in a single post would be insane i could fill 30 books with it and still have more information, plus i forgot what i was going to say, but any questions that are directed towards me about a specific aspect of time travel i would be happy to answer.

Owen Macri

Anubis69
April 12th, 2005, 01:13 PM
Well if you even want to be more technical doing absolutely nothing but being there could also change the timeline thereotically. Mainly because someone could glance your way and study you for two-three seconds and that changes their whole life, which would cause a MAJOR change in history. Just being there changes everything, because you were never there to look at before.
Yeah, that's in essence what i said. in theory, it is a form of interaction. i should've specified that when i said not interacting with anything or anyone i meant like being by yourself if you get what i mean. that no one sees you and you change no surroundings. basically like being in a room by yourself.

Shivan
April 12th, 2005, 01:20 PM
Yeah, that's in essence what i said. in theory, it is a form of interaction. i should've specified that when i said not interacting with anything or anyone i meant like being by yourself if you get what i mean. that no one sees you and you change no surroundings. basically like being in a room by yourself.

Even if you dressed up exactly like they did back then, even if you came in somewhere where there are NO viewers to see you come, even if you blended in with the crowd you would still have an impact. No matter what, because if you show yourself to one person your chances of preventing a change in the timeline are basically screwed.

But let's play on the other side for just a moment. What if going to the past and you did change the future? What would happen to your future? Would it just be like a click and everyone just remembers it happening the way you changed it? Like for instance would all the text books and all of that just magically change if you go back in time and save Abraham Lincoln from being assassinated?

It's fun to think about, because you just have no idea.

Jarnin
April 12th, 2005, 01:36 PM
I am fond of the theory in which when you go into the past timeline you create a new timeline instead, but your timeline still exists. But the person above said you couldn't ever get back to your own timeline, I do not see why you couldn't? You never did anything to change your timeline, because this theory prevents that by creating the new timeline. Say your friend saw you get in the machine and POOF be gone. Nothing has changed for your friend, and you are still gone and missing. You could come back a day later and explain what happened on your trip.
Well, with those two rules I stated above, just the act of you traveling back to the past changes the past.There are a couple reference points you have to consider:

Your personal timeline: No matter when you travel to, you still have a personal timeline that always moves into the future.

Your home timeline: In other words, you were born, grew up, and eventually traveled to the past. All of this would happen in your home timeline.

Your alternate timeline: When you left your home timeline, the act of traveling to the past creates an alternate timeline. The idea is you weren't in the past in your home timeline, so when you travel to the past, that act creates a new timeline.

The reason why you can never go back to your home timeline is the fact that you traveled to an alternate timeline when you traveled back in time. If you create a new timeline by traveling back to the past, then decided to travel back to the future, it'd be the future of the alternate timeline you created, not your home timeline.

What it really boils down to is this: Traveling forward in time allows you to stay in the same timeline. Travel backwards in time forces you to travel to an alternate timeline.

Shivan
April 12th, 2005, 01:42 PM
Well, with those two rules I stated above, just the act of you traveling back to the past changes the past.There are a couple reference points you have to consider:

Your personal timeline: No matter when you travel to, you still have a personal timeline that always moves into the future.

Your home timeline: In other words, you were born, grew up, and eventually traveled to the past. All of this would happen in your home timeline.

Your alternate timeline: When you left your home timeline, the act of traveling to the past creates an alternate timeline. The idea is you weren't in the past in your home timeline, so when you travel to the past, that act creates a new timeline.

The reason why you can never go back to your home timeline is the fact that you traveled to an alternate timeline when you traveled back in time. If you create a new timeline by traveling back to the past, then decided to travel back to the future, it'd be the future of the alternate timeline you created, not your home timeline.

What it really boils down to is this: Traveling forward in time allows you to stay in the same timeline. Travel backwards in time forces you to travel to an alternate timeline.

Yes, by traveling the future of the new timeline you would not be able to go back to your Home Timeline. But what about the ability to travel to other dimensions? With this you could travel to the past by time-travel and then travel back to your home timeline and reality with dimensional travel.

If you think about it, that works.

Anubis69
April 12th, 2005, 01:59 PM
But let's play on the other side for just a moment. What if going to the past and you did change the future? What would happen to your future? Would it just be like a click and everyone just remembers it happening the way you changed it? Like for instance would all the text books and all of that just magically change if you go back in time and save Abraham Lincoln from being assassinated?
That's the way i always thought about it. Like it happened in "mobius". They changed the past and they only remember that version. I like that alternate timeline theory. it's the best one i've heard so far

Matt G
April 12th, 2005, 03:09 PM
Actually, Matt, there have been stories about the theories of time travel (ex: "The Sound of Thunder", a short story). The theory in most of these stories (and, I believe, including "Moebius") is that the smallest change in the past, due to the forbidden presence of a time traveler, can change the course of the entire future. I mean, look what happened with SG-1: all they did was try and steal a ZPM, a simple task, right? Well, that simple task ended up in the deaths of more than half of SG-1, and the total alteration of the course of the future.

So, my belief:

I don't really believe time travel is possible at our current level of technology. I think at some point, somebody with the right idea will achieve it. But, even if we do manage to somehow achieve time travel, I think it's a science that man was not meant to mess with.

Yes time travellers can change the future. However, SG1 changed the future without causing servere paradoxes as you suggested earlier. The only result was some fairly major changes to the scenario in the 21st century. The game did not actually end.

Therefore, the only actual paradox that is possible is the Grandfather paradox or some other combination of changes to the scenario that destroys the time machine in the past AND prevents it from being built in the future!

Shivan
April 12th, 2005, 03:18 PM
Yes time travellers can change the future. However, SG1 changed the future without causing servere paradoxes as you suggested earlier. The only result was some fairly major changes to the scenario in the 21st century. The game did not actually end.

Therefore, the only actual paradox that is possible is the Grandfather paradox or some other combination of changes to the scenario that destroys the time machine in the past AND prevents it from being built in the future!

I believe that the Grandfather paradox completely shatters that certain time-travel theory. If I were to go back in the past and kill my grandfather I thereotically wouldn't be able to kill him because I couldn't have gone in the past. Unless the time changes directly after I kill him, but what do I do then? I vanish in thin air? He couldn't of died by me unless I was born, which if he died I wouldn't be born...

I understand now why they consider it a paradox...

Supreme Thor
April 13th, 2005, 09:41 AM
I don't think I could really add to this conversation anymore than I already have. It was fun though :D

Matt G
April 13th, 2005, 09:58 AM
I believe that the Grandfather paradox completely shatters that certain time-travel theory.

How. Going back to my scenario, it would only gome into effect if something that 2005 me did in 1995 eventually resulted in me getting killed before I built the time machine.

Or are we misunderstanding each other?

Shivan
April 13th, 2005, 12:12 PM
How. Going back to my scenario, it would only gome into effect if something that 2005 me did in 1995 eventually resulted in me getting killed before I built the time machine.

Or are we misunderstanding each other?

I'm completely confused right now... LOL. Which is pretty funny.

Hmm...

Ok, I'm thinking about it like this-

Let's say I build a time machine tomorrow on April 14th, 2005. Ok, that's simple I'm sure you're not having any trouble following me yet. :p Now I get in the time machine at 5 p.m. and travel back to April 14th, 1960 at 5 p.m. So far my timeline looks like this-

|---------------X3-----------------------X1-----------------X2---------


X1: May 7th, 1985 (When I was born)
X2: April 14th, 2005 (19 years old)
X3: April 14th, 1960

During this time I have kept aging, even though I myself have gone back into 1960. My timeline is still the exact same.

Now, let's say I kill my grandfather. Or let's say I do something that, at least, causes him to not meet my grandmother or to *cough*do what you know*cough* with her... Well if I have stayed on the exact same timeline and not created an alternate second one then I should thereotically just vanish. Along with everyone else that came from my Grandfather and grandmother in the future. To be more specific, the same future would be completely different.

Understand?

Matt G
April 13th, 2005, 01:28 PM
Yeah, that I agree with. If you do anything that eventually leads to your younger self or your parent/grandparent/direct ancestor getting killed before they've had kids...you have a paradox as you will longer be around in the present day to travel in time.

Shivan
April 13th, 2005, 01:35 PM
Yeah, that I agree with. If you do anything that eventually leads to your younger self or your parent/grandparent/direct ancestor getting killed before they've had kids...you have a paradox as you will longer be around in the present day to travel in time.

This may be stretching it but it's at least worth mentioning, if I did travel back and kill my grandfather it could very well destroy the universe... I mean... If you think about it...

It's like going back in time and cutting out a hole...

Maybe not though, it's just theory.

SG Zero
April 13th, 2005, 02:19 PM
To answer the whole at light speed/FTL travel to time travel is ridiculous. When moving towards closer and closer to c (light speed, 3.0E8 m/s) means that to you, your reference frame, that time is the same... but from the original reference frame, where you left, the time is moving the same there. It's called the twin paradox. Anyway, from the original reference frame you would look younger and from your reference frame the original reference looks younger because they're moving at c according to you. In comparison of the two frames using the original reference, your time is moving slower. You will not move backwards... You can only slow your time down while the Universe moves at normal time. You just wouldn't know it went by, the best visual example I can think of is the first episode of Andromeda when it was stuck in a blackhole... Oh... yeah you don't need to travel at the speed of light to cause these dillations, but the almost infinitely high acceleration or extremely immense gravity which is a type of acceleration. The only problem is that when you are moving at the speed of light and come back, the decceleration causes you to catch up what you had missed... So this isn't a possible way to time travel.

This does though show that with enough gravitation force/acceleration you can slow time down without being effected by the catch up effect. To time travel, you'd need a machine about 10 m or so in radius, of course, about the mass of Jupitor and place it on Earth. Time will move faster on Earth while you won't experience any change. This would oddly enough make Earth your moon... You'd also die from the pressure inside... But hey! You're time hopping now.

Theoretically, you can only move forward in time because you can't change prior events. Although this is amended assuming that whatever happened in the past was caused by the future, meaning that the past happens first. The time paradox comes into mind, but if the past never happened then the future would not do it. A person could not go back in time to kill themselves because the future would not happen making it that the person didn't kill himself thus goes on living and would never have the chance/ability to come back and kill himself. If that person was killed by another person in the future, then that person is destined to do it regardless. This creates a problem of unaccounted mass in the universe... So the person must go back to the future, or like in Ninja Turtles III, something has to be displaced.

This of course doesn't help... Another theory is that if you do time travel, you change another time line creating a new alternate dimension provided you can send yourself to the right time and place which is a lot harder to do. You would need an anchor in your present time to go back, but nothing would change. In fact, to live in the future of the new time line you made, you'd need another time machine to send you there. This causes the issue of unaccounted mass again though... As you can see these theories have plenty of holes. Stupid general relativity....

Matt G
April 14th, 2005, 12:57 PM
This may be stretching it but it's at least worth mentioning, if I did travel back and kill my grandfather it could very well destroy the universe... I mean... If you think about it...

It's like going back in time and cutting out a hole...

Maybe not though, it's just theory.

Depends on your definition of 'destroying the universe'. Sticking with my travel back to 1995 story. If my 2005 self's doings in 1995 eventually led to my death before April 2005 then the exact result is going to be time as we know it stopping and getting replaced by a loop going between April 1995(or whenever exactly my past self gets killed) and April 2005, flipping between two versions of history: One in which I live to April 2005 before going back in time and another in which I get killed before April 2005.

Shivan
April 14th, 2005, 01:14 PM
Thanks for your thoughts SG Zero!!!

Matt G -

I'm not sure I buy into the time-loop thing. You're thinking about the loop like this right?

|-------------------------------------------X1------------------------X2
...............................................................|------------------------- |


IGNORE THE PERIODS.

X1 1995
X2 2005

So you are saying that a continual loop will be created in which our time will lead until the act of me causing me not to be born occurs? But what about everyone else that isn't affected by the loop? People across the world?

You're not counting everyone, and if you do you will understand that the universe can't sustain a loop. It would fundamentally be impossible. How could a reality, or 1 reality and our timeline for that matter, stay on a continual loop forever? At the point I stop myself from being born would I vanish and 1995 start all over again? Until it happens again?

I don't understand, can you clarify yourself?