Time Travel - Possibility and Speculation

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SUMMARY

The forum discussion centers on the feasibility of time travel, with participants debating the potential for future advancements in technology to enable such phenomena. Key theories include time travel to the future through relativistic flight and wormholes, as well as the concept of stasis. The discussion highlights the challenges of traveling to the past, citing the laws of thermodynamics and the linear nature of time. Participants reference Stephen Baxter's novel "Ring" and Stephen Hawking's theories, emphasizing the speculative nature of time travel and the lack of empirical evidence supporting its possibility.

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  • Understanding of Einstein's theory of relativity
  • Familiarity with the laws of thermodynamics
  • Knowledge of wormholes and their theoretical implications
  • Basic concepts of cryogenics and stasis
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Anyone interested in theoretical physics, science fiction enthusiasts, and individuals exploring the philosophical implications of time travel.

elibol
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I am curious to see what your opinions are on the odds of Time Travel accually being achieved...

under what circumstances do you think it would be possible?

And those of you who do believe it will be possible in the future, how much longer until it is possible?
 
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Based on current theory, time travel to the future is quite possible. However, travel to the past is not.

When technology is advanced to the point where we can go to other stars, the we will be able to travel to the future.
 
Originally posted by mathman
When technology is advanced to the point where we can go to other stars, the we will be able to travel to the future.

Possibly sooner, depending on your definition of time travel! Aside from the obvious analogy that we're traveling to the future right now, one could also consider stasis to be 'time travel' from the perspective contained within the field of stasis. However, I believe you're correct that there would seem to be no way to travel back in time. Not only is this true, but it is logical. To travel back in time is absurd, to travel forward is not. Then again, consider what was considered 'absurd' 50 years ago compared to now. ;)
 
Time is down to sequence and duration, so under our current paradigm it would not be possible. Yes you can travel into the future, as we are all doing at the moment.
Hello all you time travellers !

It's possible that one day it may be possible.

How to achieve Time Travel ?

It you take a clock - a very simple clock with a direct drive from a motor - and you reverse the battery, the clock efectively runs backwards.
That is what would be required to time travel, but slightly more complex.
You would have to find a way of reversing the natural sequence of events. Low pressure flowing towards High pressure - you would have to effectively reverse the laws of thermodynamics.
If that was possible, and you could encase yourself in a bubble of reversed thermodynamics, then maybe you would get the desired effect.

As for when it would be possible. If it is possible in the future, then it already possible now, assuming we were interesting enough for somebody to travel back and observe us.
 
Methods for time travel.

There are many theoretical methods of time travel.

The first is simple: Just freeze yourself, and then thaw when the time is right. That could have problems, though. The cryogenics could mess up, and you might be stuck in liquid nitrogen for near eternity without waking.

Another method is very clever, but quite time consuming. You set off on a relativistic flight with a wormhole, and the time dilation causes you to "skip" elapsed time to a point where you stop. The wormhole has two connections: The one back in the past, and the one with you. You can stay in the future for as long as you wish, and you can enter the wormhole back to the past when you are ready. You may have to wait a few decades before you finish the timelike-trajectory.

There is one more method I know of: Closed timelike curves. Apparently when you got in a circle, you'll end up where you were a little while later. If you went fast enough, you'd be back at where you started before you went, so you would achieve a fraction of a step into the past. If you kept on doing so, you could apparently go thousands of years or more back to earlier events. Unfortunately, you would need cosmic string, and other exotic materials to achieve such a Back-to-the-Future-esque flight.

The latter two methods were described in Stephen Baxter's novel, Ring. Methinks a grand novel, and you should read it sometime, along with the others. Have a long life and prosper well.

\\//,
 
thnx flashheart =]

for those of you who said that it is only possible to travel to the future, why is it obsurd to travel to the past? and have you read hawkings lecture on space and time warp?

http://www.hawking.org.uk/lectures/warps.html

i think what he's saying here is that its possible to go back in time in a similar method that flasheart said...

thnx guys, your opinions mean a lot to me, and give me better prespective on what's realistic and what isnt...
 
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Originally posted by elibol
for those of you who said that it is only possible to travel to the future, why is it obsurd to travel to the past? and have you read hawkings lecture on space and time warp?
The arrow of time is linear and flows in one direction only for a number of reasons. Depending on how you see it, the 2nd law of thermodynamics is a reason or a manifestation of that.
think what he's saying here is that its possible to go back in time in a similar method that flasheart said...
He doesn't mention it and warping space is not the same as warping time.
 
If time travel were possible in the distant future, then the chances are we would already know about it.
There would certainly be at least one individual with a wicked sense of humour who would have influenced our history in some small way.

A dinosaur dug up and found to be wearing a Rolex (taken from a book I read once) or a Roman soldier with a bag full of 20th century coins.

I cannot believe for one moment that if time travel was possible, that there would not be some indication of it. That it would be so restricted or policed to never let idiots leave things behind.

Unless, it's a conspiracy and our governments already know of its existence...
 
ok, well one more thing, there is this thing i read->

http://freespace.virgin.net/steve.preston/Time.html

i donno, it seemed pretty persuasive to my neutral mind set on the matter.

it speaks a lot of einsteins theory on relativity, but i really didnt understand much of the math, or much of the connections they made, leaving me helpless in attempts to analyze the matter...

if anyone has run across anything like this themselves, or if they have taken the time to read a little bit of the link i produced, i would like there views on it...

i mean, until there is some evidence of it (which i have come across, if you search for 'john titor' on google) i really have no other choice but to get on with my life... since i don't posses the knowledge to figure it out myself... i am determined to understand the nature of time better though from your replies...

and, if time travel to the future is only possible, is there anyway to go back? or is that dependent on your method of time travel?

if there is it 'seems' to me this method could be manipulated to travel to the past...

i am guessing not since there is no scientific evidence supporting time travel to the past...

thnx guys.

1love to the peeps on this forum -_-;;
 
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  • #10
also, besides a brief history of time, are there any books you guys could recommend for a good start on a better understanding of time, space-time, and good detailed information on space-time relationships with a minimal amount of mathematics?

and maybe a tutorial on how the Minkowski Diagram functions?

also maybe something that would enable me to understand the mathematics in books based on space-time? (this is for if there is no book that could possibly fully explain to me the nature of space-time without mathematics)

a book that when I am finished reading i will say to myself 'hmm, this makes sense' ?

thnx thnx thnx
 
  • #11
Here's a link to some stuff that may be of use.
http://casa.colorado.edu/~ajsh/home.html

One aspect of time travel that should not be overlooked is the amount of energy in the Universe.
If you travel back in time from now, when you go to, that point in time will exceed the total energy in the Universe by the amount of energy you contain. This may cause a few problems.

It may be that if time travel is possible, you can only go into the future, and return. And in doing so ensure that you maintain the total energy.
You would have to isolate your energy now and ensure it doesn't alter, even by one photon, until you arrive at your destination time. This would mean that your own time line would have been frozen at your point of departure.
The result being that you could go into the future, but nothing of you would exist in that future, so the future you see wouldn't be reality.
When you return, you cannot be sure that anything that you experienced will actually happen, because your time line will be restarted which will alter some part of the future.

Hope that's clear.
 
  • #12
hmm, very convincing man! this makes sense to me thnx...

hmm... but if your original timeline freezes doesn't that insure that there will be no energy imbalance when you return?

besides this, wouldn't you radiate energy while in the future? and wouldn't this radiated energy cause the disturbence in your own timeline when you return (like a lower count that what was, and you think there could be some overlooked law of time travel that regulates this energy mismatch somehow that we don't now of because time travel has never been attempted?)? if this is the case, why bother with the future energy isolation seeing as you will be altering the energy balance in your timeline when u return anyways? or would the mechanism you have have to funnel the energy back to your timeline somehow?

thnx 4 link and reply -_-;;
 
  • #13
When you reached the future you would start to radiate energy, you would also be absorbing energy as well.
When you are ready to return to your own time, or any point in between, you would need require a special device, the Localised AWolf Time Travel Equilizer ( LATTE for short ) This device would force you to loose or gain energy to match the amount you arrived with, thus maintaining the balance.
 
  • #14
Originally posted by elibol
i mean, until there is some evidence of it (which i have come across, if you search for 'john titor' on google)
FYI, John Titor is either a hoaxster or is mentally ill. I haven't read enough about him to know which.
 
  • #15
aaaaaaaaaa that was uncalled for. but i guess i see your point awolf...

but i think it is the lack of knowledge we BOTH have on the matter that it turned into a mockery...

i was on your level, but apparenty you were full of it to begin with =]

and arent we being a tad narrow minded russ?

doubt has always been a method to suck humans into a believe, but the consideration shouldn't be ignored completely. if you had read more and given more info instead of stating he is mentally ill and what not then i would have respected your opinion without writing this.

dont get me wrong, i still respect your opinion regardless of your lack of interest and research on the guy...

the way i see it you have looked at the cover and judged...

but apparently he has made a prediction that there will be a civil war in the USA between the dates of 2005 and 2008.

if it is a hoax, the possibility of a civil war breaking out is still possible, regardless of his prediction.

one simple reason: the 'bombings' of the world trade centers and everything that has come from that...
 
  • #16
Elibol, this is all pure speculation as there is no proof that time travel is possible.
The reverse is also true, nobody can provide proof that it isn't.

Anything is possible until proven otherwise, and even then it may still be possible.

An interesting quote I read recently on http://groups.msn.com/TheoreticalPhysicsCosmologyandotherSciences spoke about UFOs and that they travel in time rather than space. The quote was from a guy called Sherman

'they' don't travel through time but rather "around it".

This adds another dimension (no punn intended) to time travel.
 
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  • #17
well, i can certainly say i like this reply better than the other one... i am not trying to prove anything to anyone with no evidence or scientific observation man...

but when my curiosity and interest in something is mocked... i feel pretty violated... thnx for the info, this is very interesting as well...

yo, where in this link is that quote?

now that i think of it, around time? i mean, i don't even really have a visual depiction of what traveling thru time would look like, and around is just a term relevant to space...

that doesn't flow yo...

imma take this to the philosophie forum -_-

i think it has evolved out of the context of being realistic at this point...
 
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  • #18
Time travel would likely be instantaneous from your perspective, since you're not actually moving in any dimension except time. Speaking of which, I've seen a lot of comparisons of time to space. IE, if we can move both forward and backward in space, why can't we do the same in time? It's been explained to me on another thread that time is not a spatial dimension.

In regards to going 'around' time, I believe the reference is similar to the standard two-points-on-a-piece-of-paper example for describing how a wormhole might work. If you haven't heard of it before, it goes like this:
Consider two dots on a piece of paper. What is the shortest possible distance between these two points? The answer seems simple, a straight line, right? Wrong. The shortest distance is to fold the piece of paper so that the two points touch. The distance is now zero, and you can travel there without moving! The question is, how to bend spacetime such that two desired points connect. Stephen Hawking seems to have a lot to say on this subject... I suggest finding some of his literature if you're really interested in the wormhole idea.

In regards to:
There is one more method I know of: Closed timelike curves. Apparently when you got in a circle, you'll end up where you were a little while later. If you went fast enough, you'd be back at where you started before you went, so you would achieve a fraction of a step into the past. If you kept on doing so, you could apparently go thousands of years or more back to earlier events. Unfortunately, you would need cosmic string, and other exotic materials to achieve such a Back-to-the-Future-esque flight.
In order to go fast enough that you arrive just as you depart, you would have to be traveling at an infinite velocity. In other words, you don't travel you just are. As if that doesn't seem difficult enough, in order to arrive before you depart, you'd have to go faster. In other words, this theory assumes it's possible to go faster than infinite velocity.

Finally, one last note. In regards to:
I cannot believe for one moment that if time travel was possible, that there would not be some indication of it. That it would be so restricted or policed to never let idiots leave things behind.
Hmm... hope I don't offend anyone but... how about that Bible? Or perhaps... Stonehenge? Similar such features may turn out to be exactly those kind of 'traces,' but we'd never suspect it because we're so used to hearing about them.
 
  • #19
Originally posted by Pergatory
In order to go fast enough that you arrive just as you depart, you would have to be traveling at an infinite velocity. In other words, you don't travel you just are. As if that doesn't seem difficult enough, in order to arrive before you depart, you'd have to go faster. In other words, this theory assumes it's possible to go faster than infinite velocity.

The originator of the time-travel method resolved the problems of infinite velocity by giving the timefarer hyperdrive, for both interstellar travel and complex trajectories. Remember, faster-than-light travel is spacelike, not timelike. If one went in a circling spacelike trajectory, he could construct closed timelike curves, with the abnormal effect of going back through time.

Anyway, this system is impossible with our current technology. I mean, where in the universe are you going to find cosmic string? I guess I'll leave that for astronomers to answer.
 
  • #20
Elibol,
my apologies if my attempt at humour didn't go down very well.

Curiosity is what makes us what we are, without it we wouldn't have even got to the stone age.

Here's the http://groups.msn.com/TheoreticalPhysicsCosmologyandotherSciences/general.msnw?action=get_message&mview=0&ID_Message=522&LastModified=4675460193072946194 . It's somewhere near the bottom.

but i think it is the lack of knowledge we BOTH have on the matter that it turned into a mockery...
By asking questions and proposing any solution or method to time travel puts you right at the forefront. Nobody has a working or workable solution - not the last time I looked.
It was not intended to be a mockery, and I still think the thread is valid.
You made a very valid point, that if the total energy is to be concerved, then it must work both ways. It proves that you thought the problem through. If only everybody was the same.

Hmm... hope I don't offend anyone but... how about that Bible? Or perhaps... Stonehenge? Similar such features may turn out to be exactly those kind of 'traces,' but we'd never suspect it because we're so used to hearing about them.
Too subtle, ite would have to be something far more obvious.

A better example would have been the city gates in Alexandria. Built on the orders of Alexanda The Great, they were hydrolic with a pressure plate mechanism - now that was cute, but not an indication of time travellers.
 
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  • #21
awolf, apologie excepted man. no hard feelings...

flashheart, what is cosmic string?

pergatory, that folding the paper thing really cleared some visualization issues for me... thanks man =]

and also, in order to achieve near light speeds or beyond, would you need to be in orbit of something? or would you like just go thru space in a straight line?

like a spacecraft build to orbit around mars, or some other planet with near to none atmosphere...

do black holes have anything to do with time travel?

and also, if someone could produce a link for me on black holes that'd be the bomb digety.. thanks...
 
  • #22
elibol,
I posted a link earlier in this thread. It's got some good explanations and animations about Black Holes.
Here's the link
A Black Hole is just an extremely dense object. The closer you get to the centre, the more compressed matter becomes. There's no reason why a Black Hole would punch a hole through SpaceTime, as some have theorised.

In regards to going 'around' time, I believe the reference is similar to the standard two-points-on-a-piece-of-paper example for describing how a wormhole might work.
The problem with warping space is that you are merely reducing the distance between 2 points, there's nothing that will cause time to reverse.

Time is a bit like an elevator in a tall building that always goes up.
If you were to reduce the distance between floors, the elevator would still go up, you would just reduce the time taken to get to a higher floor. Likewise, if you changed the speed of the lift, you would take a different amount of time to reach another floor, but the floor would always above the one you're on.

To be able to time travel, you need to get off the elevator. This is the bit about going around time.
You need to find another elevator that is going down and use that.

However you manipulated our SpaceTime, you would still be on the same elevator going up.
 
  • #23
oh, yea man i added that link to my fav's =] i didnt know it had stuff on black holes.. sweet


umm

when i think of it in that sense it is pretty impossible to travel back in time... i like the metaphor but i can think of ways around it still, but i get the point =]

still though, traveling to the future doesn't seem too unlikely thru the wormhole method though right?

and they say your mass will just keep growing the closer you get to the speed of light, and eventually your mass becomes infinite...

wouldnt you... die?

it seems like you would be a giant or something, but how? like isn't this mutating you?

i am learning so much =]
 
  • #24
The idea of a wormhole is that it will be a shortcut between 2 points in the universe.
It would not provide a method of time travel, just distance.

As for traveling at the speed of light, or even faster than light, well the jury is still out on that one.

My own belief is that the maximum velocity an object can travel will be just short of the speed of light - about 93% or 173,000 miles per second.
I would be interested to know if any particle accelerators have gone beyond this - thus disproving my theory.

The reason for this is that if we assume that the speed of light is the maximum speed in the universe - through normal space. Then all the electrons orbiting the atomic nucleus at the speed of light will also be restricted to this maximum velocity. As you accelerate their orbits become laterally extended (Lorentz's transforms).
At a velocity close to the speed of light the electrons will be traveling further in a forward direction than laterally to a point where their orbits would become unstable.
If I'm correct then your mass would increase by a factor of about 3 before you would loose atomic structural integrity and merely bits would start falling off.

This does put a bit of a dampener on traveling to the future, because, as time dilation is in the same proportion to relativistic mass, you would only be able to slow time by a factor of about 3 - to travel 300 years into the future would take you 100 years.

Not really worth the effort.
 
  • #25
You're right about the wormholes, I hadn't fully thought that one through. However, I was pretty sure there was a method by which they could be used to travel through time. I believe maybe that was two wormholes with singularity endpoints, because of the warping of spacetime around the gravity of the singularity. I think that's the same theory the famous Mr. Titor claimed to make use of.

Anyway, as far as available options for traveling to the future, let's not forget stasis (e.g. cryogenics). It will always be an available method and although it may not take you directly to the future, it will allow you to be unaware that time is passing until 'the future' arrives. Just don't forget to arrange for someone to let you out! ;) Otherwise you could find yourself traveling much further than you intended, or even being lost forever.

AWolf, in regards to your postulated maximum speed, that's an interesting viewpoint that I hadn't heard before. However, the whole idea that the speed of light is the maximum speed never made much sense to me. It seems to be a very lenient rule. For example, have you heard of the experiment where they passed a beam of light through a certain substance (I forget what it was) and essentially the beam left the substance before it entered! In other words, it was going faster than light. However, they later discovered that it was not actually speeding up, but the "peak" of the beam's pulse was moved farther forward to look more like a burst than a pulse, while the whole of the beam remained unaffected. This means that some of the photons in the beam must have been moving faster than light in order to cause this shift.

Another quarrel I have with the idea that the speed of light is the maximum speed is that speed is relative. In other words, relative to some distant galaxy, we are probably traveling greater than the speed of light right now. Speed is a human idea, there's no reason for physics to limit our speed except by providing friction.
 
  • #26
Originally posted by elibol
I am curious to see what your opinions are on the odds of Time Travel accually being achieved...

under what circumstances do you think it would be possible?

And those of you who do believe it will be possible in the future, how much longer until it is possible?

a)We travel in time all the time .In future all the time.It can be accelerated more simple than something like return back in hystory.For instance by gravity waves or getting in and out of orbit of the system of black holes.
b)Back in time?Nooo..I don't believe it will ever be possible.Simple reason is arrow of time and Causality for massive objects.
Pandan like Pauli's principle.Something must preserve this not to happen in the sense we imagine it.
 
  • #27
Another quarrel I have with the idea that the speed of light is the maximum speed is that speed is relative. In other words, relative to some distant galaxy, we are probably traveling greater than the speed of light right now.

Even the light emitted from an object traveling at a very high velocity, does not exceed the speed of light either relatively or actually - sounds strange, I know.

Time dilation on the object will slow time in proportion to the velocity. The velocity of light relative to the object will appear to be the speed of light due to the time dilation.
A stationary observer will see the light emitted from the object at the speed of light with the object traveling at a slower speed behind it.

Our own Velocity
Our Time, and our Mass, is Relative due to us currently traveling through the Universe at approximately 1% the speed of light.
It is Relative to some stationary point in the universe where there is no graviational forces - Universal Standard Time (UST).
Due to our velocity and position in a gravitational field, we run slightly slower than UST.
 
  • #28
the experiment where they passed a beam of light through a certain substance (I forget what it was) and essentially the beam left the substance before it entered!
I read something about this, that it wasn't actually the photons that arrived at the target, but their identity.

Maybe it was something similar to what happens when a voltage is passed down a wire. The voltage travels at the speed of light with the result of an electron popping out the end, but the electrons themselves travel far slower.
 
  • #29
so you would prolly be dead by the time u got there..., that would be cool... well, can you slow time down, so your timeline went beyond you?
 
  • #30
Hello,

I believe that reverse time travel may be possible. I posted a theory about its possibility in another forum and was unable to get any contradictions or support for my theory.

https://www.physicsforums.com/showthread.php?s=&threadid=13214

The theory was based on a particle view of the universe, but now I'm starting to believe that the physical universe may be made up of standing waves. Combining my previous theory with a standing wave model, to travel backwards in time you would only need to stand in the path of the waves traveling backwards in time. These waves would have to be of the correct frequency to interact with the waves that make up your body in such a way as to create movement backwards in time.

A simple model would be two high powered electro-magnets placed some distance appart. One would be activated at the time of departure, and the other would be activated at the time of arrival. The magnetic pull will need to be great enough to break the force which prevents particles from changing their direction of movement through time (time-velocity). It would need to be pre-determined which waves were traveling forwards in time, and which waves would be traveling backwards in time. If you were in the "future" and steped into the waves traveling forwards in time you would simply be bombarded by [particles<->standing waves] and not actually travel anywhere. On the other hand if you were to stand in the path of waves traveling backwards in time they should carry you backwards in time.

The major problem with such a portal is that it could only be used in a sequence of "receive"<-"send" "receive"<="send" , any attempt to receive at a mid point would intercept the particles traveling backwards through time and any attempt to send at a mid point may work, but would most likely cause interference with future sends meant to reach the initial "receive" charge. Such intereference would likely kill a time-traveler, or they would simply arrive at the "forward" end of the electro-magnets (which hopefully will be above ground in-case such an accident were to happen).
 

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