Is Timetravel possible?

  • Thread starter ManDay
  • Start date
  • #1
ManDay
159
1
The question, very short cut: Is timetravel (as we are getting it showed in movies) possible, "yes", "no" or "dunno" (science doesn't know)? How can antimatter in terms of the SM be interpreted as matter moving backwards through time? Is there any possible better understandable depiction to this?
 

Answers and Replies

  • #2
aerospaceut10
139
2
Time travel into the future is a possible idea due to the time dilation from Einstein's Theory of Relativity.


There are supposed ways of getting around time travel to the past, like creating parallel universes each time it's done or whatnot. But I wouldn't count on that idea too much, haha.
 
  • #3
Loren Booda
3,119
4
Wormholes may be one exact solution of general relativity, known as an Einstein-Rosen bridge. Whether they will prove practical in the future depends a lot on whether they can be kept from closing upon the traveler.
 
  • #4
PAL_PHYSICS
3
0
Thank you Loren Booda.
 
  • #5
Is Timetravel possible?

--------------------------------------------------------------------------------

The question, very short cut: Is timetravel (as we are getting it showed in movies) possible, "yes", "no" or "dunno" (science doesn't know)? How can antimatter in terms of the SM be interpreted as matter moving backwards through time? Is there any possible better understandable depiction to this?

Anyway (and take it with a smile; it's a joke) yes timetravel as we are getting it showed in movies or more generally everywhere around us is possible : because our own life is a timetravel. And to realize that, you don't need any wormhole or complicated science.
Blackforest
 
  • #6
pallidin
2,209
2
Experimentally, localised distortion of both space and time have been observed by a massive rotating object causing such distortions around it's edge peripheral. This phenomenon is called "frame-dragging"
Any object placed within that peripheral region will experience the effect.
However, this is early science, and much has to be learned to utilize and/or modify this effect to a useful level.
 
  • #7
ManDay
159
1
I've heard about all those theoretical aspects, what I concern tho (sorry, I didn't say that) is wether going back in time, changing the "timeline" and returning to the current time is possible.

Could this even be possible? If I'd "transfer" mass into another time, it would "pop up" there and hurt the law of conservation of mass and energy, right? If I'd experience disorted time do to dilatation, what would it look like?
 
Last edited:
  • #8
rockerdoctor
34
0
Theoretically, yes it is possible. Einstein theorized that space and time are one single thing and must be referred to as space-time. Gravity is simply the curvature of space-time. The very fabric of space-time is bent by massive objects. If we could somehow bend space-time far enough at two points we could travel through this bent space or hole, known as a wormhole, and travel to places in time. Physics allows us to do this because of our vantage point. Looking at a clock inside a wormhole will read a different time than if you were to look at one outside the wormhole, giving you totally different perspectives, as if you were going to a totally new time. This of course is entirely theoretical at this point and hasn't been made by man... yet.
 
  • #9
ManDay
159
1
Okay, but what is the solution to this famous paradoxon then? If I really bend time so I can move back to an earlier point in time and all other dimensions are retained, and I prevent my earlier self from doing what I did - will this affect my very self me again?
Or should time travel rather be seen as a travel to an alternate dimension where time is shifted so my original dimension stays unafffected beside my disappearing from it? If so: Wouldn't the "travel" to another dimension contradict mass-energy conservation?

Furthermore, if we assume that "dimension travel" is actually possible and - at the same time - presume that there are at least ten different dimensions (this is something which emerged from SST, isn't it? Am I allowed to bring this in?) which suppose an infinite numbers of alter-realities, wouldn't that imply that there is at least ONE alter-reality, where people already invented a device which enables them to timetravel and should have visited US?

My knowledge on this is really limited, as you can see. I'm sorry if the above sounds absolutly stupid and unprofessional :-(
 
  • #10
rockerdoctor
34
0
none of that sounds stupid at all. those paradox are complexing questions theoretical physisits ask all the time. the answer is no one knows. many people believe that time travel will never happen based upon those reasons. so i guess we will just have to wait and see what happnes, if it ever does. and yes the interdimensional travel is one theory out now, but again, no one knows for sure exactly.
 
  • #11
cristo
Staff Emeritus
Science Advisor
8,140
74
Okay, but what is the solution to this famous paradoxon then? If I really bend time so I can move back to an earlier point in time and all other dimensions are retained, and I prevent my earlier self from doing what I did - will this affect my very self me again?
This was recently discussed here:https://www.physicsforums.com/showthread.php?p=1743502#post1743502.
Or should time travel rather be seen as a travel to an alternate dimension where time is shifted so my original dimension stays unafffected beside my disappearing from it? If so: Wouldn't the "travel" to another dimension contradict mass-energy conservation?
One would need to think more carefully about what "mass-energy conservation" means in this instance.

Furthermore, if we assume that "dimension travel" is actually possible and - at the same time - presume that there are at least ten different dimensions (this is something which emerged from SST, isn't it? Am I allowed to bring this in?) which suppose an infinite numbers of alter-realities, wouldn't that imply that there is at least ONE alter-reality, where people already invented a device which enables them to timetravel and should have visited US?
Why do you need to invoke extra spatial dimensions for this argument? I would imagine that in this case there are some precise laws governing where you can actually travel to; for example, a commonly held belief is that one cannot travel back to a time before the time machine was created. Does this hold for the one that you are traveling into?

As an aside, I think this thread is drifting further and further away from Physics!
 
  • #12
doc.madani
90
0
i think it is possible with much more research.
 
  • #13
Big Walt
4
0
The school of thought is still out on this one. There are a lot of possible developments coming from the new Hadron Collider in Cern is not fully operational yet but the price tag for this instrument is over 6 billion dollars, a capital B for billion, and that’s a lot of money. To further answer your question is time travel possible, the answer so far is that no one really knows for sure. Some people say no way and others say yes. Some people say the Hadron Collider is capable of producing a Einstein Rosen Bridge to the past. The problem is that if it does create the bridge it will only be the size of an atom. To small to step through, so a lot of experimental work needs to be done. I went to the CERN page a copied the below to give you some understanding of how this machine will work.

(LHC) is a gigantic scientific instrument near Geneva, where it spans the border between Switzerland and France about 100 m underground. It is a particle accelerator used by physicists to study the smallest known particles – the fundamental building blocks of all things. It will revolutionise our understanding, from the miniscule world deep within atoms to the vastness of the Universe. Two beams of subatomic particles called 'hadrons' – either protons or lead ions – will travel in opposite directions inside the circular accelerator, gaining energy with every lap. Physicists will use the LHC to recreate the conditions just after the Big Bang, by colliding the two beams head-on at very high energy. Teams of physicists from around the world will analyse the particles created in the collisions using special detectors in a number of experiments dedicated to the LHC. There are many theories as to what will result from these collisions, but what's for sure is that a brave new world of physics will emerge from the new accelerator, as knowledge in particle physics goes on to describe the workings of the Universe. For decades, the Standard Model of particle physics has served physicists well as a means of understanding the fundamental laws of Nature, but it does not tell the whole story. Only experimental data using the higher energies reached by the LHC can push knowledge forward, challenging those who seek confirmation of established knowledge, and those who dare to dream beyond the paradigm.
 
  • #14
cabraham
1,180
89
I've pondered this question all my life and attempts at an answer have been quite futile. I don't think we can ever say one way or the other. But, the reason I'm leaning towards the negative is as follows. These points are worth considering.

Causality - cause and effect as we know it would be turned on its head. If a person causes an event, then goes back in time to undo it, what happens? What if a person meets his past self or future self if they go forward. If I bring an object with me to the future, say a wristwatch, and then encounter that same watch in the future, consider the following. Suppose I were to destroy my watch from the past. What would happen to the future version? Also, how can the same wath from 2 different time frames mutually co-exist. Where did the extra mas/energy come from? It's tough to get around that.

Also, there are some practical limitations that would make time travel extremely difficult. Let's use the motion picture trilogy "Back To The Future" as a reference. The Earth rotates on its axis, and revolves around the sun, which rotates on its axis, and revolves around the galaxy, which moves etc. My house is not in the same location it was a minute ago, let alone 30 years ago. When Marty went back 30 yars in time, the Earth was in a different position in the solar system, and the galaxy, etc. How did the time machine compensate for all of that? It would be a pretty remarkable feat!

I doubt it.
 
Last edited:
  • #15
Big Walt
4
0
Hi rockerdoctor...

Nice to read your reply and very well written I might add. I for one do not know the answer. Like you I have pondered this very same question is time travel possible. I initially said no way but as I kept reading a unique set of words kept popping up again and again and here is what I am reading...

A growing number of physicists are convinced that the thing we call ‘the universe’ — namely space, with all the matter and energy it contains — is not the whole of reality. According to quantum theory — the deepest theory known to physics — our universe is only a tiny facet of a larger multiverse, a highly structured continuum containing many universes.

I could easily write some deep explanation with scientific clarity but to answer your hypothesis of cause and effect and tell you that the laws that govern our universe can not be broken, but what if when you go back in time and make a change to the time line the change does not effect your future but rather a alternate future in the multiversity.

Everything in our universe — including you and me, every atom and every galaxy — has counterparts in these other universes. Some counterparts are in the same places as they are in our universe, while others are in different places. Some have different shapes, or are arranged in different ways; some are so different that they are not worth calling counterparts. There are even universes in which a given object in our universe has no counterpart

On large scales, universes obey the laws of classical physics, and so each behaves as though the others were not there. But on microscopic scales, quantum mechanics becomes dominant and the universes are far from independent. Universes that are very alike are close together in the multiversity and affect each other strongly, though only in subtle, indirect ways — a phenomenon known as quantum interference.

Without quantum interference, electrons would spiral into atomic nuclei, destroying every atom literally in a flash. Solid matter would be unstable, and the phenomena of biological evolution and human thought would be impossible. And as I shall explain, it is quantum interference that provides our evidence for the existence of the multiversity.

Through interference, its counterparts in other universes can affect each particle in our universe. What we see as a single subatomic particle is really a sprawling trans-universe structure, spanning a large region of the multiversity. Although we cannot see the parts of this structure that are outside our universe, we can infer their presence from the results of experiments.

As I said scientists are going to experiment with high speed partials at CERN so the rules have not been written yet, we have no unified theory yet. We just do not know what is possible. I for one hope for time travel, can you just imagine knocking on your families door in say 1941 would they believe you came from the future or just call the cops saying you are a madman. No one would ever believe you. I remember an old saying... we have met the aliens and they are us…. Have a great day Big Walt
 
  • #16
Big Walt
4
0
This message is the answer to cabraham not rockerdoctor...very sorry for the name mix up...
 
  • #17
ptalar
69
0
Time travel into the future is a possible idea due to the time dilation from Einstein's Theory of Relativity.


There are supposed ways of getting around time travel to the past, like creating parallel universes each time it's done or whatnot. But I wouldn't count on that idea too much, haha.



Aren't we already traveling into the future but at a very slow pace?
 
  • #18
humanino
2,490
8
I did not read the entire thread. I want to point out the quantum instability of any time-travel device (I did not see it mentionned before).

Any time-travel device used to open some sort of "bridge" between a spacetime point and another one in its future is plagued with a quantum instability. Quantum fluctuations, for instance in the electromagnetic field, will amplify themselves quite like in a laser and have your device blow up.

As Kip Thorne showed, the only way to avoid this is to have negative energy density making the "structure" of your wormhole. This seems to me like a no-go theorem, because negative energy density, as of our current understanding of physics, is an oxymoron.
 
  • #19
rewebster
843
2
Is Time travel possible?

I'd say --No
 
  • #20
mcknia07
282
6
I'm sorry, I don't think it's possible
 
  • #21
Santa1
109
0
Aren't we already traveling into the future but at a very slow pace?

If you ask me, at a perfectly fine pace =)

I think time travel is unlikely (atleast back in time), because there are'nt a lot of tourists from the future.
 
  • #22
Dark Fire
40
0
Time travel into the future is a possible idea due to the time dilation from Einstein's Theory of Relativity.

Yes sir.
http://youtube.com/watch?v=oRWwI61so5Q"

I think time travel is unlikely (atleast back in time), because there are'nt a lot of tourists from the future.

That was my philosophy as well, a year ago, though I also found several philosophies "destroying" that again: for instance this might finaly occur in the very vast future, meaning they have very strict rules for time traveling, and some sort of a bug-free automatic system that does not allow these rules to be broken under any circumstances.
Also, as the man from the Youtube video (claims to be working on first Time Machine) states that time traveling is only allowed from the point of no return where the first Time Machine is started.

Aren't we already traveling into the future but at a very slow pace?

Yes.
So the question remains: how may we affect the speed of time to increase or decrease?
 
Last edited by a moderator:
  • #23
Kenny_L
127
0
Aren't we already traveling into the future but at a very slow pace?

Well, 'slow' is relative, as is 'fast' is also relative.
 
  • #24
Kenny_L
127
0
think time travel is unlikely (atleast back in time), because there are'nt a lot of tourists from the future.

I agree. They'd be here by now, and we'd be over-run with problems...like if there's an infinite number of times that an infinite number of people could come back to some point here in time and space, we'd be over-run. This is assuming the 'classical' interpretation of traveling in time/space - where we go back to a point in the past and everything picks up from there. This also brings us to chats about different time-lines, different parallel worlds/realities etc. Anyway, we haven't been over-run, and we haven't had the whole world getting a big public broadcast about people coming back from the future with sophisticated technology...etc...so just based on observation ... it just looks like 'classical' time travel can't happen.
 
  • #25
Blackout-Bill
7
0
Think about it, if time travel was possible then if you did travel back in time then vthere would be a moment where time kept reversing and time would have to cease to exist
 
  • #26
cristo
Staff Emeritus
Science Advisor
8,140
74
... This also brings us to chats about different time-lines, different parallel worlds/realities etc. ...

Well, that or it could simply be that one cannot travel back to a time before the time machine was created.

Blackout-Bill said:
Think about it, if time travel was possible then if you did travel back in time then vthere would be a moment where time kept reversing and time would have to cease to exist
I don't really know what you mean here.
 
  • #27
Kenny_L
127
0
Well, that or it could simply be that one cannot travel back to a time before the time machine was created.

True! Even though I was talking about 'classical' time travel...or the kind of time travel that the fans all want...where you can just travel back in time and space independent of when the time machine was made.

I think that one thing to be considered is that if we could somehow travel back to a point in time and space (in the 'classical' way), we would probably be inserting more matter/energy into the universe... because all of a sudden, the universe (in the past) would be injected with whatever the time machine takes back with it (that's us, and the machine itself). So all of a sudden, the past universe has more energy, which then messes up the theory of energy cannot be created or destroyed...well, at least this is the current theory for our part of the system anyway.
 
  • #28
humanino
2,490
8
the Youtube video (claims to be working on first Time Machine)
We have discussed Mallett's claims already somewhere else in this forum. From the beginning it seemed wrong. Since then, Mallett has not even answered to published articles explaining the flaws in his ideas. Interestingly enough, you can go talk to him in person at the university, and I know very well people who did, it so happens Mallett does not get founds for his machine, although he asks for very little... Seriously, read would it be only wikipedia before believing in Mallett's work.
 
  • #29
campal
7
0
I've been told that as a person approaches the speed of light, time relative to others being viewed slows. when you make the speed of light ( if possible, I’m aware of distance change and mass increase and of the immense amount of energy needed to possibly reach this speed to push that mass) time for others stops and past the speed of light time goes back wards. Does this huge mass increase make an objects gravitational force so immense that it drops through space time and can continue traveling at higher speeds then light? Such could be possible in the even of a star becoming too heavy and dropping through space time to create a black hole. BUT what happens as you slow down? As in all the particles in your body slow down to absolute zero, where your temperature and kinetic motion would be zero. Would this result in forward time travel? Does mass decrease?
 
  • #30
Kenny_L
127
0
I think that one thing to be considered is that if we could somehow travel back to a point in time and space (in the 'classical' way), we would probably be inserting more matter/energy into the universe... because all of a sudden, the universe (in the past) would be injected with whatever the time machine takes back with it (that's us, and the machine itself). So all of a sudden, the past universe has more energy, which then messes up the theory of energy cannot be created or destroyed...well, at least this is the current theory for our part of the system anyway.

When I meant 'past universe', I just meant the whole system...in the past... which means, if you exist in the future and then you are able to go back to some point in the past (where you assume you could even see yourself), then you'd be introducing more energy and matter. Otherwise if you didn't introduce more energy and matter to the environment as you enter that environment in the 'past', then you have to wonder whether you need to lose something ... from somewhere else.
 
  • #31
campal
7
0
that's good food for thought. sometimes i wunder if time really exists. just because you can use it to callculate projectil motion or whatever, is it actually a physical issue or is it just the human way to deal with a situation? do you know what i mean? what if clocks can tell your passage from the past to now but nothing actually happened in physics, only things that can age have, from diferent forms of decay. if time is not real then time travel would not be possible and a lot of the physics equations would be wrong...E=MC^(2)?
 
  • #32
ptalar
69
0
that's good food for thought. sometimes i wunder if time really exists. just because you can use it to callculate projectil motion or whatever, is it actually a physical issue or is it just the human way to deal with a situation? do you know what i mean? what if clocks can tell your passage from the past to now but nothing actually happened in physics, only things that can age have, from diferent forms of decay. if time is not real then time travel would not be possible and a lot of the physics equations would be wrong...E=MC^(2)?

I am not sure time exists either. Just change. Stars are born, die. People are born and die, etc. Time is a frame of reference created by man to measure change. Information exists though and if one can travel at multiple speeds of light they can view the past by viewing the light as it reflects off the earth. If one had a super powerful telescope and could travel to anywhere in the Universe in an instant, one would be able to say travel instantly 100 light years away from Earth and be able to watch events as they unfold on Earth for the past 100 years as if they were there. Of course you would have to travel 100 light years in an instant which is 600 trillion miles. At sub light speeds we only travel into the future.
 
  • #33
malawi_glenn
Science Advisor
Homework Helper
Gold Member
2022 Award
6,205
1,699
i think it is possible with much more research.

I think it is possible to do squared triangles with much more research
 
  • #34
DaveC426913
Gold Member
21,387
4,843
Just to address a few misconceptions:
and past the speed of light time goes back wards.
...
No object with mass can reach - let alone exceed - the speed of light. No object without mass can travel at less than the speed of light. NBothing can cross the barrier from <c to > c.

However, hypothetical particles (called tachyons) travel faster than the speed of light, yet still cannot slow down to c. They would, if they existed, appear to be moving backwards through time.

Does this huge mass increase make an objects gravitational force so immense that
The mass increase due to relativistic speeds does not increase an object's gravitational force. The mass increase is from an external observer's POV. The object reads its mass as normal.
 
  • #35
robheus
146
0
none of that sounds stupid at all. those paradox are complexing questions theoretical physisits ask all the time. the answer is no one knows. many people believe that time travel will never happen based upon those reasons. so i guess we will just have to wait and see what happnes, if it ever does. and yes the interdimensional travel is one theory out now, but again, no one knows for sure exactly.

All of our current physics is based on only one dimension and direction of time,and the only deviation that relativity brings in that two independent frames of reference might have different "speed" of time (time dillatation), with as a consequence that two clocks can get out of sync without any mechanical/techincal failure, but solely due to relativistic effects.

I don't know if physical law is possible at that basis of another, independent dimension of time, I would guess that it is not a possible physical reality.

And if that is not the case, then there is no possibility of time travel.

One might consider the case in which not just the speed of time (which is a possibility based on relativity) but also the direction of time could change.
However, I would guess that inverting the direction of time would in fact not be different at all, since in such a case all physical laws is time-inverted too, including the physics of our brains, and we would (in this opposite directed time) remember the future (which is the past in our normal flow of time) and would not be aware of anything different.
 

Suggested for: Is Timetravel possible?

Replies
3
Views
697
Replies
5
Views
577
  • Last Post
Replies
7
Views
328
  • Last Post
Replies
12
Views
446
Replies
42
Views
3K
Replies
13
Views
2K
  • Last Post
Replies
9
Views
425
  • Last Post
Replies
7
Views
646
  • Last Post
Replies
18
Views
464
Replies
1
Views
130
Top