Is time travel possible?

[lxxvii24]

guys, i persoally believe thr is nothing like freewill or desztiny being changed as most ppl in the religious fate profess The thing is that when anything happens that seem to change one's destiny, then it means that at one point in the creation of the individual in question it was his destiny that h \is destiny be changed. So travelling back in time to me is a reality and that it is a possible phenomena.

[Johnny5]

Originally Posted by Johnny5

 

If you are just fooling around, instead of trying to learn that is one thing.

 

 

what exactly do you mean by this

 

I said that several days ago, but I went back and re-read it and I think I meant this...

 

You don't have to be serious about physics. No one has to.

 

But, for those who are serious about the question, it falls into the domain of physics.

[Sayonara]

he was joshing you

I certainly was not.

[Zeo]

I certainly was not.

Well, could you perhaps clarify it? I'm sorry, but I can't seem to find which one you explained it in.

[ed84c]

he means (i think) that rules that we know of are not ALWAYS obeyed in exotic cirucumstances, take QM for instance.

[Zeo]

I remember Star Gate SG-1, where one of the Tolan said this: "Ah, Quantum Physics, the tragic fallcy of science . . . "

 

Paraphrased.

[paganinio]

1,I just remembered someone suggested that the only way of time travel be 'watching the past events without changing them'. I had thought what the difference is between 'watching past events and changing past events'. It might make sense to me now 'cause if you just watch it history won't be changed. But when you 'see' something photons already go into your eyes so you actually will have changed them as well.

2,Should time travel be true in the future(and in my sci-fi book written 2 years ago), some elite 'Time Soldiers' with hard training are required. Such training may include 'Body getting used to Counter-clockwise Effect', for example when you travel through time, the water you have drunk will go all the way up to your mouth and so on.

[Daecon]

Time travel can't really be possible, because that would mean that at one point in time in the universe, there is more total mass/energy than at another point in time in the universe.

[Zeo]

That was what Johnny was getting on about:

Conservation of Mass.

 

But that's assuming those laws are uniform throughout the universe.

[Sayonara]

It's also assuming that conservation always applies but extra-specially just not throughout time, despite the fact that we're necessarily treating it as a continuum because we are discussing a barrier to travel through it.

 

Which is, of course, all very silly.

[J.C.MacSwell]

Time travel can't really be possible, because that would mean that at one point in time in the universe, there is more total mass/energy than at another point in time in the universe.

 

So you might randomly get sucked into the future just because some numbskull from the future trys to get into your present?

[Sayonara]

So you might randomly get sucked into the future just because some numbskull from the future trys to get into your present?

...which, in fact, is another reason why the "conservation" refutation is broken. Us not understanding the "rules" doesn't mean they aren't there.

[Kylonicus]

Time travel is possible I think.

 

According to Gunter Nimtz, the lead researcher on superluminal tunneling kept doing research on the faster than light phenomenon, and he, being a conservative in physics came the the conclusion time travel is possible, but the duration of which a particle goes back in time is so short, that it can't possibly be used for any practical purpose(i.e sending back those lotto numbers). Essentially it can't be used to violate casuality.

 

Superluminal tunneling works off of the uncertanity principle which basically states that anything is possible, just not probable on the quantum level.

 

At least that's what I think that paper of his said, my memory is sketchy.

However, sending a particle back in time and a human back in time are two COMPLETELY different things, and furthermore, you would only be sent back like a billionth of a second, which in reality serves no purpose whatsoever.

 

At least that's what I think that paper of his said.

[rajama]

What if we divide the journey into a thousand billion steps?

What if we send back a qubit?

[Vladimir]

If we are all travelling at the speed of light (our speed in the fourth dimension being that of the speed of light minus our speed in the three) then we couldnt actually move beyond the speed of light. This is my understanding.

We are still thinking of time as a straight line. Where there is a bckwards a front ect, because that is how we percieve it.

if we do factor conservation laws into it, then time travel is either impossible, or you would have to "transport" an equal mass from the "past" to teh "future"

[rajama]

I got the impression that time machines theorised by (say) Tipler or Thorne conserve mass etc. at their 'entry' and 'exit' points.

 

Remember, only the traveller witnesses the journey...

[Sayonara]

if we do factor conservation laws into it, then time travel is either impossible, or you would have to "transport" an equal mass from the "past" to teh "future"

For the last time, that does not necessarily hold true. If conservation is your only "barrier" to time travel, then you are accepting a navigable and inseparable space-time continuum, which renders the conservation barrier meaningless.

[unknow force]

Is time travel possible?

 

i have an theory, well suposely we travel in the time if we go faster than the light (but that isnt confirmed), well maybe if we increase our lenght wave we could make "quantum jumps", so the "space -time ship" could be an sistem that would be freezed to near 0 Kelvin and jum faster than the light.

[rajama]

You get around it via an unbelievably simple excision method, as I have already said in two threads.

 

Where are the threads that mention the 'excision method'?

Can't find a reference to 'excision'...

Tried to google 'excision time travel' and ended up with this thread... huh

[Sayonara]

I don't think I actually used the term "excision method" in the other threads.

 

Just check for the most recent threads dealing with time travel and conservation.

[Doc Who (Jr)]

nuts, i made my own thread but i overlooked this one, if neone here has looked at my thread ("time travel(is it possible?)"), they will kno im currently working on a theory that will determine whether time travel (as in changing direction) is possible, now i dunno if more experienced scientists are working on that or have worked in it in past years so if neone would like to notify me of them it would prevent me looking like a fool thnks.

[5614]

It is generally accepted that time travel is not possible throughout the physics world, except for the fact that we're already travelling through time and time dilation etc.

 

Although I'm sure you'd find stuff on google... just remember, just because it is on the internet doesn't mean it's true!

[NLN]

Here's why I don't think it will be possible for a human to ever travel either forward or backward in time: both time and motion would prevent it.

 

Why time itself is the problem:

 

Let's say we have built a time machine. A human steps into it, expecting to be transported to another time. But because he has a physical body composed of trillions of spatially separate and distinct molecules, each molecule would have to be simultaneously transported and reassembled at the other end. It would all have to occur at exactly the same instant, because if it did not, one part of the body would dematerialize / materialize while another part had not yet done so -- essentially tearing the human to pieces. Since it has been shown that there is no such thing as an exact, static instant in time -- the very premise is impossible.

 

Why motion is the problem:

 

Think of the Earth spinning on its axis; the Earth revolving around the sun; our entire solar system contained in one of the arms of the Milky Way, revolving around the galactic center.

 

If we were to transport a human back in time, where would we send him? The present day Earth is in an entirely different location than it was in the past, or will be in the future. In fact, it is now in an entirely different location than when I began this sentence! In order to "land" a body in the past, for instance, one would have to know the exact coordinates of every molecule of that body -- both in the present and in the designated "landing site" of the past.

 

If you began to transport your body to the entrance of Central Park as it was exactly 50 years ago, a second later the Earth will have rotated on its axis some thousands of meters -- not to mention the movement of the entire solar system, etc.

 

You see my point? There are no precise instants of time or space from which (and to which) we may instantaneously move. Hence, the entire process is impossible.

 

Machines Like Us

[Edtharan]

Let's say we have built a time machine. A human steps into it, expecting to be transported to another time. But because he has a physical body composed of trillions of spatially separate and distinct molecules, each molecule would have to be simultaneously transported and reassembled at the other end. It would all have to occur at exactly the same instant, because if it did not, one part of the body would dematerialize / materialize while another part had not yet done so

This is only true if you assume that the time machine acts a bit like the transporters from start trek in that it has to dematerialise the matter to go back in time.

 

If you used a massive gravitational field and rotated it, then it would twist space/time so that one of the dimentions of space was rotated into the dimention of time and that the dimention of time was rotated into that spatial dimention. In this case, time travel would be like walking up or down a road. There would be no materialisation or such. You could even set it up (well if you had the technology to do this you could) so that you could actually walk on your own feet.

 

The big probelm with this kind of Time Machine though is that you can't go back before the Machine was built.

 

If we were to transport a human back in time, where would we send him? The present day Earth is in an entirely different location than it was in the past, or will be in the future. In fact, it is now in an entirely different location than when I began this sentence! In order to "land" a body in the past, for instance, one would have to know the exact coordinates of every molecule of that body -- both in the present and in the designated "landing site" of the past.

But if you were using the type of machine I described above (or another like specially set up wormholes), then you would appear out the other side of the machine whereever it is. So if the end of one "mouth" of the machine was set for "Central Park West" and the other for "Central Park East", then because you can't go back past when the machine was built, you must come out from the other mouth where it was located at the time you arrive. The "mouths" would travel with the Earth (and Central Park)and therefore you would appear there.

 

But even if you had a time machine that could travel to an arbitary time without the need for some kind of exit structure (like the Time Machine in "Back to the Future"), then all you would need to do is build it into a space ship so that when you traveled you coudl set it so that you appeared in empty space and then had a means to travel to the spatial location you desired.

[Donut.Hole]

Picture time as a line.

 

Right now, you are moving slower than light, so the line advances straight. The faster you move, the more the line bends, causing time to move forward slower. When you move faster than light, time will bend back upon itself, and you will be back in time.

 

Now, if only we had a Star Wars hyperdrive . . .