The REAL reason time travel will neverwork

[Krade]

For any and all purposes, this thread assumes that building a time machine is possible.

Some years ago I came across this revelation about time travel. If you made a time machine, one that could take you to the exact same spot only in a different time, you would find yourself in a very... unfortunate place. You see, if you travel to the exact same place, only at a different time, the Earth will be, regretably, someplace else. Even if you move forward or backward 1 second, you'll be nearly 30km from where you were on Earth (not taking into account universal expansion or galactic rotation). That 30km will most likely be either 30km above the ground or 30km below. Either one doesn't sound very pleasant.

So, basically, my hopes for the future are that if anyone does make a time machine, they take this into account first, and instead make a time/space machine. Which, even then, you would need exact universal coordinates or else become lost in space and die slowly and never be found or lodged in the earth and die quickly and never be found.

[Amotis]

They'll just take 1d6 points of damage for every ten feet they're ejected from.

[Rawhide]

It all depends on if the earth is moving, or if the universe is moving around the earth.

[Amotis]

Or if the universe is expanding, detracting, or staying the same.

[Vonriel]

I subscribe to the theory that time travel will never be possible. Wanna know why? In the future, at some unknown point, it will be invented. Then, further beyond that, someone will realize that it would be catastrophically stupid to allow it to exist, so they'll travel back into the past and muck up anything involving it. This will be a reoccurring event, as humanity as a whole shouldn't be trusted with something as powerful as time travel, so time travel will never actually exist.

[SDF]

If works if you have a phone booth that uses a series of tubes.

Or a Delorean.

[TigerHunter]

It all depends on if the earth is moving, or if the universe is moving around the earth.
Back, heliocentric! *brandishes crucifix*

[Krade]

That's true...

Since the universe is (supposedly) infinite, then it both has no center AND every point in it is the center because every point in the universe is equally far from the edge (which doesn't exist... maybe)

GACK! tetra-simu-posted!

[Skippy]

It all depends on if the earth is moving, or if the universe is moving around the earth.

Funny thing, I thought it moved around me...

[/narcissism]

[Rawhide]

Back, heliocentric! *brandishes crucifix*

Just to keep it really simple: Albert Einstein's Theory of Relativity In Words of Four Letters or Less (http://www.muppetlabs.com/~breadbox/txt/al.html)



Funny thing, I thought it moved around me...

[/narcissism]
It does: see above

[Breaon]

But dimesions beyond the 4th involve the compression of time-space. It may be possible, just not feasible with our current level of technology.

[Eldritch Knight]

Actually, the biggest reason why time travel will never exist is inherent in it's definition. Time is primarily relative to ones perspective, as illustrated here. If you were to travel close to the speed of light, you would experience time dilation to the fact that you would not be able to percieve the passage of time, but to an outside observer any number of years could pass. Time can never be a finite thing because it is constantly in flux, (in a process of continual change.) Time travel, unfortunatly, is something that can only exist in Science fiction, or the rare fantasy tale.

[TSGames]

But dimesions beyond the 4th involve the compression of time-space. It may be possible, just not feasible with our current level of technology.
Fools! We are the Mooninites we exist in 5 dimensions.
http://i34.photobucket.com/albums/d141/stevepants/mooninites.jpg

[SDF]

Well if you exceed the speed of light you should technically go back in time, but because anything with a mass at the speed of light has an infinite mass exceeding that is beyond our ability.

[Krade]

Fools! We are the Mooninites we exist in 5 dimensions.
http://i34.photobucket.com/albums/d141/stevepants/mooninites.jpg
You win the thread...

Edit: Remember, we are assuming all the technicalities of the actual "changing what time you are in" has been solved and are no longer an issue here.

[Gaelbert]

I like the Timeline explanation of it by Michael Crichton... even if it may not be true.

[Vuzzmop]

It all depends on if the earth is moving, or if the universe is moving around the earth.


Seriously?

[Amotis]

Fools! We are the Mooninites we exist in 5 dimensions.

THOUSAND!

Mmm yes, five thousand.

[Rawhide]

Seriously?Yes .
Albert Einstein's Theory of Relativity In Words of Four Letters or Less (http://www.muppetlabs.com/~breadbox/txt/al.html)

[Midnight Son]

So, basically, my hopes for the future are that if anyone does make a time machine, they take this into account first, and instead make a time/space machine. Which, even then, you would need exact universal coordinates or else become lost in space and die slowly and never be found or lodged in the earth and die quickly and never be found.If one were to build a machine to such specs, why limit yourself to this earth, one could travel to any point in time and any place instantaneously. Alpha Centauri, here I come. That or the Patriot's cheerleaders locker room shortly after their next home game.:smallbiggrin:

[Skippy]

If one were to build a machine to such specs, why limit yourself to this earth, one could travel to any point in time and any place instantaneously. Alpha Centauri, here I come. That or the Patriot's cheerleaders locker room shortly after their next home game.:smallbiggrin:

Ditto on that...

And I just needed to say, both of them can leave you breathless...

[Gaelbert]

Using a time machine as a teleportation device. I've thought of that before. If you're already playing with spacetime, you might as well make the most of it.

[Otterella]

Of course, you're forgetting that time travel does exist. We are all travelling through time into the future at the same rate. Just because we can't go back doesn't mean it doesn't count as travelling.

[Jibar]

If works if you have a phone booth that uses a series of tubes.

Or a Delorean.

Eighty-eight miles per hour!

My God I love that film.

[Dean Fellithor]

I'm going back in time to make this thread never exist, lol.

but anyway, Time travel: wont work till Hell freazes over, maybe not even then...

[Skippy]

Eighty-eight miles per hour!

My God I love that film.

One point twenty-one jigo-watts!!!

Best film EVAR

[Ikkitosen]

Well if you exceed the speed of light you should technically go back in time, but because anything with a mass at the speed of light has an infinite mass exceeding that is beyond our ability.

Read all about autodynamics (http://www.autodynamics.org/main/) for other, less well accepted ideas on this.

[Eldred]

I've always seen travelling into the past to change the future impossible. This is mainly because, technically, right now, those people have already tried to change the future (which is today). Yet everything's still the same. They could have hit the earth with fifty nukes, but because it's already happened, today will still be the same.

Plus it would be one hell of a way to make dinosaurs extinct :smallwink:

[I'm da Rogue!]

Funny thing, I thought it moved around me...

[/narcissism]

Hey! I was about to say that!!! Grrrr :smallfurious:

[Maroon]

Read all about autodynamics (http://www.autodynamics.org/main/) for other, less well accepted ideas on this.
But if exceeding the speed of sound creates a sonic boom, what happens when you exceed the speed of light? Ouch.

[Pink]

A question, what is this revelation based on exactly? You state it isn't universal expansion or galactic rotation but you don't say what it is. I'm guessing you might be basing it on the rotational speed of earth around the sun, but wouldn't that just mean if you could time travel you'd have to do it in year increments?

Course I know nothing on this subject but eh, conversations are fun.

[Ikkitosen]

Response to ^^, damn simu-ninja! :smallwink:

Yeah, but the grandfather paradox is easily answered by the whole "the timeline branches whenever a decision is made, and thus there are virtually infinite different realities out there" argument. Your time machine just ctakes you between these and gives you the chance to create more branches. How is of course a completely different argument.

[Call_me_Fate]

Gee. This is funny, because I find that I have already discovered the secret to time travel. There, I just did it again. Whump, there again, I am slowly, steadily traveling forward in time relative to a fixed point in time. Learn how to control the travel? That I am not as sure about.

[The Great Skenardo]

So it would be more accurate to say that you're falling through time, yes?

[rollfrenzy]

I have discovered how to stop time.

All you need is an office, a desk, work to do, and a REALLY nice day outside. Believe me, time will come to a screeching halt.

[Call_me_Fate]

Very very true that.

[Rex Idiotarum]

Time Travel is simple, in space/time, you have three dimensions (Let's keep it simple, but I'm willing to admit there might be twelve) and Time. X, Y, Z, T. T is constantly increasing. The other coordinates change as the objects moves.

But a wormhole can be set to two ends, One at any coordinate at the X,Y,Z, T axises. Now, depending upon how you create a Wormhole time machine, you really don't need to worry about all that, because they work on either one of two principles, one, you grab a an end to a Wormhole, jump on a fight at lightspeed around the world for so long, so that the end of wormhole doesn't age, but the one on earth does, and bam, you have a two-way trip to the past.

The other method involves multiple universes. This is exactly like in timeline. In quantum foam there are millions of wormhole opening and closing all the time, you may have a few in you right now. All one has to do is open the one with the end they desire, and bam, they are in the past. Or at least a parallel universe set slightly in the past but still effects the original world. This method often involves killing people and rebuilding them. Frankly, I'd be afraid to try it.

That said, Grandfather Paradox or Predestination paradox? I say if you keep your original wormhole open all the time you move through it, you can't travel to a screwed up future, so you can write off Grandfather Paradox. But the Predestination paradox sounds not only fun, but logical. Do you really think you ever had a choice with any action you've ever taken?

[The Great Skenardo]

That's something like the whole Fate argument. But if you don't know what precisely is "supposed" to happen, you can't very well try and foul it up.

In other words, if you don't know what fate has in store, it's the same as Fate not existing at all.

(Try not to read too deeply into that, Call_Me_Fate :smallwink: )

[Rex Idiotarum]

Fate? It's Math. If there are so many variables to every decision, and if you could figure out ever variable, then you can predict the result of the decision, action, or whatnot. As a butterfly flapping it's wings on the other side of the world moves the air just enough to cause a storm on this side of the world, the small lizard that scared it away was provoked into going near it, and what provoked it did whatever it did because of another thing.

[Shadic]

Time Travel will never work, just because the universe is sick and tired of trying to work out the consequences of it.

At least, that's my theory. It already gets confused enough by the whole "Time slowing down when you're moving really fast." thing.

[The Great Skenardo]

Fate? It's Math. If there are so many variables to every decision, and if you could figure out ever variable, then you can predict the result of the decision, action, or whatnot. As a butterfly flapping it's wings on the other side of the world moves the air just enough to cause a storm on this side of the world, the small lizard that scared it away was provoked into going near it, and what provoked it did whatever it did because of another thing.

Pascal's Demon. But then there's the very chaos theory that you invoke with the butterfly effect. To determine the exact implications of each...thing in the universe, you'd have to have explicit knowledge of everything about it. And I do mean everything, down to the exact position and momentum of its individual atomic particles. However, once you get down to that scale, uncertainty starts becoming an issue and complete omniscience becomes impossible.
Yet it cannot be ignored or approximated if true Math is to be invoked here, for, as you stated, the smallest of things eventually has the greatest of impacts.

[Shadic]

The smallest of things eventually has the greatest of impacts.

*Shadic attempts to resist the urge to link to YTMND...


And fails!*

Push it to the Limit! (http://homersimpsonlimit.ytmnd.com/)

[Rex Idiotarum]

Yes, the smallest things can make the big difference, and even though you're saying it is impossible to know exactly how the future will unfold, you agree with me that the future is already decided.

When you couple the Butterfly effect with the Grandfather Effect, just by opening up a portal to the past, or stepping into it briefly could change all of time forever. Al Gore could be president, and a major storm patterns wouldn't've hit they way they did, Katrina could've moved further north, or furtherer south, and not had as much effect.

Couple with the Predestination Paradox, you see how everything fits together.

[Sewer_Bandito]

Some years ago I came across this revelation about time travel. If you made a time machine, one that could take you to the exact same spot only in a different time, you would find yourself in a very... unfortunate place. You see, if you travel to the exact same place, only at a different time, the Earth will be, regretably, someplace else. Even if you move forward or backward 1 second, you'll be nearly 30km from where you were on Earth (not taking into account universal expansion or galactic rotation). That 30km will most likely be either 30km above the ground or 30km below. Either one doesn't sound very pleasant.


That's not true! If you go back in time, then everything moves back with you. So if you went back 30 years, you'd still be on the earth, because the earth rewinds with you.


Or even going back one second, the earth with go back 1 second with you, to where it was at 1 second ago. So either way, you're fine.

[The Great Skenardo]

Yes, the smallest things can make the big difference, and even though you're saying it is impossible to know exactly how the future will unfold, you agree with me that the future is already decided.
*snip*

Not in any meaningful fashion. Like I said, if you don't know what Fate has in store, then it's exactly the same as there being no fate at all.

It's something of a meaningless statement to look at the past and declare "That was all destined to happen. Nothing could have changed it." Because nothing Did change it.

[Rex Idiotarum]

But we are talking about Time travel. In this scenario, we know what the future holds because we've been there.

[The Great Skenardo]

No, what you have is some memory of the future in your mind when you get back, which may well prove to be unreliable, depending on what you take it into your head to try and change.

An exciting possibility; the universe is not strictly causal.

[Vonriel]

Skenardo, I only feel it's proper to warn you: He won't stop arguing his position, even after you've clearly proven him wrong. He's like.. an argument addict.

[The Great Skenardo]

Heh. I know; I've seen Rex post before on these forums.

Luckily, I have fun in virtually any discussion held online, as long as the subject isn't one that makes me uncomfortable.

[Telonius]

Interesting thought about the predestination paradox... what does knowledge of the paradox do to change anything? It's possible that the most rational thing would be to behave as though the paradox didn't exist.

[Bor the Barbarian Monk]

I want to say something...Something that would be...y'know, smart-like. But what continuously pops into my head are numerous movies and books that have dealth with time travel, as well as the concepts of non-linear equations.

The latter comes to mind because of the infinite variables that pop up with the idea of going ANYWHERE in time. Forward, backward, or even sideways! Time is a rough concept for many to cover because it branches at each nano-second. The very moment you open your eyes in the morning, your first conscious decision splits time in countless directions. Do you get up and get a drink? Do you get up and use the bathroom? Do you stay in bed? If you stay in bed, do you just lie there or go back to sleep? On and on, each event splitting off into more branches of time.

It's compounded by events that you are not even witness to. If you stay in bed, but know you should go to work, do you call in sick? Do you blow off the job altogether because you planned on quitting? What does your absense at work do? Will others pick up the slack, or does your not showing up create trouble for the business in some way? Is that trouble a mere inconvenience to others, or does it cause the eventual collapse of the business? What if the day you chose not to go to work was the same day a fellow employee was going to have the courage to ask you out on a date? Have you simply put off the romance, or did you just ruin the chances of living happily ever after for all parties?

I was once given a brief version of a time travel story, in which time travel was offered as a vacation. The most popular event to visit was the execution of Christ. Before going on the trip, parties were given proper attire and taught exactly how to behave so they would not disrupt the timeline. Thus, the main character went back to witness that which made religious history...and came to the eventual realization that EVERYONE bearing witness was a visitor from the future! (Wish I could find this one and read it, myself...but was never given a title or author.)

Another tale I enjoyed immensely was The Guns of the South, by Harry Turtledove. The premise is that the Army of Northern Virginia, during the American Civil War (or Second American Revolution), is given AK-47s.

The movie Timecop, filled with terrible acting and mediocre action, at least had a story that I found interesting in terms of time travel.

Back to the Future is now a classic when it comes to pondering the complexities of time travel. It's much darker counterpart, The Butterfly Effect, also did a great job at bending the brain.

Want a dark bit of reading about time travel? Try The Doomsday Book, by Connie Willis.

I'm rambling, now. This is a topic upon which I could go on forever. I do that sometimes...I talk and talk, but manage to say nothing at all. :smalleek:

[dungeon_munky]

This thread has made me wonder how fast the sun is moving, as we base our speed relative to the sun's position. It could be hurtling through the nothingness of the universe at near the speed of light, and we wouldnt notice because we are moving with it. That definately causes some problems with the whole time travel business (though I don't think backwards is possible-time has one direction and going backwards is just something people dreamed up to dream about fixing their mistakes)

As for going faster than the speed of light, speed of light=infinite mass=infinite gravitational pull=the whole of existance in an infentesimally small point instantly. Don't do it, you'll break everything.

[Indon]

It doesn't look like anyone else has pointed it out, so I'd like to note that, courtesy of the theory of relativity, there is a known and viable (albeit prohibitively expensive) method of time travel at this very moment.

Simply get in a spaceship and accelerate to a substancial portion of the speed of light. While you move at your speed, everything else will move faster. Then head back to where you started, decelerate, and you will find that everything else has moved ahead of you in time; relatively speaking, you have gone back in time.

Edit: I'd also like to note that, due to time dialation on acceleration, there is no speed of light limit in the perception of an accelerating body; you simply increase your speed infinitely while other objects observe your relative timeframe slowing (BUT, you still maintain all the momentum of your linear speed increase, which coincides with why your effective mass is greater).

[averagejoe]

It doesn't look like anyone else has pointed it out, so I'd like to note that, courtesy of the theory of relativity, there is a known and viable (albeit prohibitively expensive) method of time travel at this very moment.

Simply get in a spaceship and accelerate to a substancial portion of the speed of light. While you move at your speed, everything else will move faster. Then head back to where you started, decelerate, and you will find that everything else has moved ahead of you in time; relatively speaking, you have gone back in time.

I was going to say that. Cryofreeze works equally well too, and probably saves energy or, at least, uses up energy in more controllable amounts. Plus you don't have to worry about space dust and radiation and all that messy stuff.

[Icewalker]

DAMN I never noticed that.

Hehehehehehe ouch.

Nice.


Now if you could build a machine that teleports through time back to itself, so you could only go back as far as it was built, it would work :smallcool:

[Indon]

Now if you could build a machine that teleports through time back to itself, so you could only go back as far as it was built, it would work :smallcool:

The first thing I thought of when I read this comment was the Heinlein book "A Door into Summer".

[Krade]

A question, what is this revelation based on exactly? You state it isn't universal expansion or galactic rotation but you don't say what it is. I'm guessing you might be basing it on the rotational speed of earth around the sun, but wouldn't that just mean if you could time travel you'd have to do it in year increments?

Course I know nothing on this subject but eh, conversations are fun.

Huh, guess I forgot to mention where the whole 30km thing came from, but it would be wrong now to assume no one could figure it out since you did without too much trouble.

Yes, the Earth move around the sun at approx. 30km/s. I said not taking into account universal expansion or galactic rotation. They are still factors and probably much greater ones than the Earth's speed around the sun. I left them out because I thought it might be easier to understand what I meant with only one speed affecting the hypothetical situation. That and I didn't feel like looking up the speed the sun rotates around the galaxy (or the rate of universal expansion, for that matter)

[TARDIS]

If works if you have a phone booth that uses a series of tubes.

...

You rang?:smallbiggrin:

However, on the topic of time travel, even though it is plausible, those from the original timeline would never realize it, never be changed by it, because of the quantum theory of reality: every choice creates an alternate universe where a different choice was made. Just try and wrap your head around that! So, even if we are able to time travel, we won't actually see any benefits from it, as those who go back in time create an alternate timeline. Really is mind-bogglingly crazy, isn't it?

Best leave it to time Time Lords, eh?

[averagejoe]

However, on the topic of time travel, even though it is plausible, those from the original timeline would never realize it, never be changed by it, because of the quantum theory of reality: every choice creates an alternate universe where a different choice was made. Just try and wrap your head around that! So, even if we are able to time travel, we won't actually see any benefits from it, as those who go back in time create an alternate timeline. Really is mind-bogglingly crazy, isn't it?

Unproven, but possible, I suppose. Anyways, it seems to me that the implications would be even greater than that. As in, there would be an alternate universe exactly identical to ours, except that on July 5th 1982 at 4:01 PM eastern time there was an atom which had a slightly different path than the corresponding atom in our universe, which produced no noticable changes to anything. So, for each moment in time, there would be a seperate nearly identical universe which would account for minute, meaningless deviations of the paths of each particle in the universe. And that's just to start.

[FdL]

Just to keep it really simple: Albert Einstein's Theory of Relativity In Words of Four Letters or Less (http://www.muppetlabs.com/~breadbox/txt/al.html)


Hmmm...Lexical density vs. grammatical intricacy...Haliday said it, IIRC. I don't think the number of letters in words have an incidence in the simplicity of a scientific explanation. It's how densely packed the propositions are, and how they relate to each other and to the facts they refer to.

But in any case it's interesting to see it done :)

BTW, everybody knows that's the first thing to take into account when building a time machine. It's an industry standard. :p

[Stormzen]

If time travel was invented in the future, people would have gone back in time and inevitably met people from the present, whatever time the present is. No time travelers have come to this or any other time, so it cannot exist.

[Jack Squat]

If time travel was invented in the future, people would have gone back in time and inevitably met people from the present, whatever time the present is. No time travelers have come to this or any other time, so it cannot exist.

but what about the whole "don't interact with people because it could change the course of history" dealie in Back to the Future. Wouldn't that make it so they're more of tourists just there to sight see?

Besides, why would you tell someone that you were from the future...it's not really something that would come up in normal conversation.

[Shiny, Bearer of the Pokystick]

I remember an awesome sci-fi story called 'the person from porlock' (referring to the person who interrupted the writing of 'kubla khan', the famous poem) about that whole interference-for-one's-own-good idea. Neat stuff.

[Nomrom]

I'm going back in time to make this thread never exist, lol.

but anyway, Time travel: wont work till Hell freazes over, maybe not even then...

Actually, hell (http://en.wikipedia.org/wiki/Hell,_Michigan) already froze over on January 24, 2004.

[Hell Puppi]

I believe there is no time travel because in the future I screwed up the world so badly with said time machine that the inventors went back into the past and destroyed it before I got ahold of it.
The only reason they didn't kill me was because I have the protection of Fenrir...that and I was a nobody up until said incidents.
You can believe what you guys want :smalltongue:

[dungeon_munky]

It doesn't look like anyone else has pointed it out, so I'd like to note that, courtesy of the theory of relativity, there is a known and viable (albeit prohibitively expensive) method of time travel at this very moment.

Simply get in a spaceship and accelerate to a substancial portion of the speed of light. While you move at your speed, everything else will move faster. Then head back to where you started, decelerate, and you will find that everything else has moved ahead of you in time; relatively speaking, you have gone back in time.

Edit: I'd also like to note that, due to time dialation on acceleration, there is no speed of light limit in the perception of an accelerating body; you simply increase your speed infinitely while other objects observe your relative timeframe slowing (BUT, you still maintain all the momentum of your linear speed increase, which coincides with why your effective mass is greater).

You won't actually be back in time. What will have happened is that the people back on the planet would be farther ahead of you....it still would be a time after your launch point.

Also, isn't there a problem with this? That is, wouldn't you also be back in time relative to earth? From the point of view of us non travellers, the exact same thing has happened to you relative to us as has happened to us relative to you. It works both ways. The planet would be ahead of you and you would be ahead of the planet. Huh?


Wait a sec...if you perceive them as going slower due to their relative motion and they perceive you as going slower due to your relative motion, doesn't this mean that there is absolutely no net change?

[averagejoe]

Wait a sec...if you perceive them as going slower due to their relative motion and they perceive you as going slower due to your relative motion, doesn't this mean that there is absolutely no net change?

No. You can tell because of which one experiences the acceleration. Remember kids: constant velocity is indistinguishable from standing still; acceleration still turns you into space-goo. From your point of view they sped up relative to you, but you experienced an acceleration and they didn't.

Also, reading that again, wouldn't you have gone forward in time, relative to where you started?

[dungeon_munky]

No. You can tell because of which one experiences the acceleration. Remember kids: constant velocity is indistinguishable from standing still; acceleration still turns you into space-goo. From your point of view they sped up relative to you, but you experienced an acceleration and they didn't.

Also, reading that again, wouldn't you have gone forward in time, relative to where you started?

Accelleration means that the reference frame is no longer inertial, and special relativity only applies to inertial reference frames. Therefore, accelleration must be negligible. And no: "moving clocks tick slower."

[averagejoe]

Accelleration means that the reference frame is no longer inertial, and special relativity only applies to inertial reference frames. Therefore, accelleration must be negligible. And no: "moving clocks tick slower."

You don't have to be constantly accelerating the whole time, just to the point where you reach near-light speed, then you can even out to a constant velocity. The earth doesn't experience that acceleration. (At least, that's what I think you were trying to say. If not, then sorry.) Anywho, there's no reason relativistic effects wouldn't occurs when you're accelerating, you just can't use the straightforward "gamma" equations in special relativity.

And, right, moving clocks tick slower. So if you go off in your spaceship at near light speeds, and a hundred years earth time have passed, but only a few months have passed for you, then you have traveled to "the future," that is, forward in time. (Note: I have no idea how correct the actual times are; I'm being kinda lazy about this, and I just picked something that seemed right. The actual amount of time is, however, beside the point.

[dungeon_munky]

You don't have to be constantly accelerating the whole time, just to the point where you reach near-light speed, then you can even out to a constant velocity. The earth doesn't experience that acceleration. (At least, that's what I think you were trying to say. If not, then sorry.) Anywho, there's no reason relativistic effects wouldn't occurs when you're accelerating, you just can't use the straightforward "gamma" equations in special relativity.

And, right, moving clocks tick slower. So if you go off in your spaceship at near light speeds, and a hundred years earth time have passed, but only a few months have passed for you, then you have traveled to "the future," that is, forward in time. (Note: I have no idea how correct the actual times are; I'm being kinda lazy about this, and I just picked something that seemed right. The actual amount of time is, however, beside the point.

This seems like what you are saying is that relativity only applies when something accelerates, as you have said that it doesnt apply to the earth which hasn't accelerated. The way I understand it, it's the relative motion, not the acceleration that causes a change in time.

I see what you mean by travelled by the future, and it was cause by me speaking poorly. By in the past I meant your clocks would be behind the earth's clocks, which I guess is actually travelling to the future. Sorry, this isnt the easiest topic to speak coherrantly about. :smalltongue:

[Bor the Barbarian Monk]

I believe there is no time travel because in the future I screwed up the world so badly with said time machine that the inventors went back into the past and destroyed it before I got ahold of it.
The only reason they didn't kill me was because I have the protection of Fenrir...that and I was a nobody up until said incidents.
You can believe what you guys want :smalltongue:

Don't you just hate when no one pays attention to your ramblings, and fail to quote you, and all that good stuff? So I paid attention and quoted you. Hope you enjoy. :smalltongue:

[averagejoe]

This seems like what you are saying is that relativity only applies when something accelerates, as you have said that it doesnt apply to the earth which hasn't accelerated. The way I understand it, it's the relative motion, not the acceleration that causes a change in time.

I see what you mean by travelled by the future, and it was cause by me speaking poorly. By in the past I meant your clocks would be behind the earth's clocks, which I guess is actually travelling to the future. Sorry, this isnt the easiest topic to speak coherrantly about. :smalltongue:

Oh, alright, I thought that you were talking about something different. What I meant is that you know which one experiences the time slowdown by which one accelerated. That is, from the spaceship's point of view, it might as well be standing still and the earth is traveling at near light speeds, yes, but time slows down for the spaceship and not the earth. How do we know the one where time is slower? Because the people on the spaceship experiences an acceleration and the earth doesn't. Remember that it is acceleration which produces relative motion; without it the spaceship doesn't get off earth, and doesn't go to near light speeds.

[Hell Puppi]

I'm completely random, so being overlooked only adds to the random.
Nobody notices the stray puppi until it comes and bites you on the leg :smallbiggrin:

[Vonriel]

Don't you just hate when no one pays attention to your ramblings, and fail to quote you, and all that good stuff? So I paid attention and quoted you. Hope you enjoy. :smalltongue:

You know what's worse? Seeing someone quote someone else, when the quote is essentially the same thing you posted, and you posted it before the quoted person posted it. :smalltongue:

[Hell Puppi]

More random! I loves it.:smallbiggrin:

[Zanaril]

Unless, if you travel through time, it also takes into account if you were moving and uses that to work out were you should turn up.

So if you travel through time while going along the motorway at 80mph, make sure you have a soft landing.

[Zeful]

I can get time travel to work.

Now I have me a time machine, instead of placeing any old coordinates I put in the same fractial equation, the Mandlebrot set (http://en.wikipedia.org/wiki/Mandelbrot_set) for example, into all the verticies. Now my time machine takes me to a place that is physically connected to all places and times that exist allowing me to experiance all the events that shape our universe, know everything and because I exsist in all times and places I can effect all worlds equally by downloading the relavent knowledge into a younger version of myself, I'm in all places and times at once so I *should* be able to affect myself. Tah dah! I now control the universe, kinda...

In this situation I can stop people from building time machines to stop me and I avoid the nasty death from being stuck in the earth or in space and could, theoretically, destroy any universes I don't like.

[RAGE KING!]

actually its been proven that time travel does exist, in fact, flying to brasil recently, i went back in time approximately 10 billionths of a second. Just ask suraj. or any number of leading physists. including einstien.



Nobody notices the stray puppi until it comes and bites you on the leg :smallbiggrin:

actually today i noticed the stray puppy, which is why it almost bit me on the leg...well more like on the foot...

[Pyrian]

actually its been proven that time travel does exist, in fact, flying to brasil recently, i went back in time approximately 10 billionths of a second. Just ask suraj. or any number of leading physists. including einstien....At which point they'll inform you that you did not go back in time, you merely changed the rate at which you're going forward in time with respect to the planet's inertial frame.

[Indon]

...At which point they'll inform you that you did not go back in time, you merely changed the rate at which you're going forward in time with respect to the planet's inertial frame.

Time is just as relative as the other three dimensions.

If everyone's running through time and you're walking, you're going backwards, relative to the runners.

[Space-Is-Curved]

There is one key problem with attempting to travel at speeds high enough to slow relative time. The rate of accelleration would have to be low so as not to tear the ship and everything in it apart because of its inertia. You would die of old age before you got fast enough to prolong your life.

I would also like to point out that I haave my own time machine in my basement. It only goes forward at the rate of one second per second.

Time is an illusion, lunchtime doubly so.

[dungeon_munky]

Time is an illusion, lunchtime doubly so.
Oh no. Do you think I should, like, put a paper bag over my head or something?

[Flabbicus]

Another tale I enjoyed immensely was The Guns of the South, by Harry Turtledove. The premise is that the Army of Northern Virginia, during the American Civil War (or Second American Revolution), is given AK-47s.


Just as an aside, thanks Bor! Someone at my summer program mentioned a book where modern soldiers went back in time with AK-47s a few days ago and now I know which one they were talking about. :smallsmile:

[RocketBard]

But if exceeding the speed of sound creates a sonic boom, what happens when you exceed the speed of light? Ouch.

You're converted into energy, when you stop... I think it would be messy.

[Space-Is-Curved]

Oh no. Do you think I should, like, put a paper bag over my head or something?

If it would make you feel any better. :smallsmile:

[teratorn]

Going back to the initial poster. Relevant velocities:

Earth daily rotation: ~465 m/sec at the Equator
Earth around the sun: ~30 km/sec
Sun around the galactic center: ~217 km/sec
Milky way around the local group of galaxies: ~600 km/sec

The local group as a whole sort of follows the expansion of the universe.

There's a lot going on during a simple second. But if you are able to go back in time you're likely also able to specify that you are tracking a particular volume of space back in time also.

Even the simple orbital dynamics of the Earth is a tricky thing, so you'd better stop every few thousand years to make adjustements. Oh, and don't forget the fact that days are getting longer (Earth daily rotation is slowing down) if you plan to go back a few million years.


But we are talking about Time travel. In this scenario, we know what the future holds because we've been there.
The thing is, if you go back in time then "that future" is your past not your future. It already happened (you lived through it, it's in your memories). The "current past" is new because you'll be going through it from a different perspective, you're adding it to your memories, and you can change it! You just need to make something happen differently from what you remember, and then the "new future" will be be something different from "the old future".

[doliemaster]

My three reasons time travel can't happen-

1.Whoever makes the device will want to change history and therefore when they change history, the future them will never have a reason to and therefore won't, and therefore the paradox cancels out the timemachine.

2.They will muck up time so they don't exist or CAN'T make the time machine.

3. Chuck Norris is the only man,women, child or anything allowed to travel in time, and will Roundhouse kick anyone who tries it.:smallbiggrin:

3 is the best reason.

[The Great Skenardo]

Well, you seem to have managed to go back in time to the span where Chuck Norris jokes were still told :smallwink:

[doliemaster]

What can I say, the first time you find them, they are pretty funny.

[averagejoe]

1.Whoever makes the device will want to change history and therefore when they change history, the future them will never have a reason to and therefore won't, and therefore the paradox cancels out the timemachine.

Unless they already changed history, which merely lead to this present. Their actions in the past were inevitable, as those actions lead to this present, and then that future.

[Indon]

You're converted into energy, when you stop... I think it would be messy.

Well, because the arrival time of light is not affected by the movement rates of objects, even if you could move faster than light, it'd be impossible to generate a 'light boom', anyway.

Example: Say two objects are moving away from each other at half the speed of light. When they are 5 LY away from each other, one radiates light towards the other. How long does the light take to get to the other object?


The answer is 5 years. Light shifts wavelength/amplitude in response to movement; light doppler effect does not effect speed, which is why you can never get the 'buildup' effect that you can with sound waves.

[McDeath]

The problem with time travel is that no one really knows how the universe works, and it would really be hard for us to understand it. It's like saying to a spoon: Well now Mr. Spoon, why is the Chinese economy growing?

Also: Time isn't a line (not a Timeline, heh). It is (as far as I understand it), like traveling to a different part of your home town, given that space and time are one.