# Is time travel possible?

• yes
57
• no
48
• uncertain
29

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Ok' date=' let's have a scenario then:

What if Man developed a device that allowed him to send himself back in time, and he did, in fact, let's say he went back 200 years. What's to stop him from doing that?[/quote']

Conservation of matter.

Regards

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Whos to say (me) that the conservation of matter is not a concept which takens into account time and time travel?

Zeo, you mention a 'device'; well really you answered your own question. A device cannot IMHO be built to go back in time.

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Conservation of matter.

Matter is not a conserved quantity.

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Whos to say (me) that the conservation of matter is not a concept which takens into account time and time travel?

Zeo' date=' you mention a 'device'; well really you answered your own question. A device [i'] cannot IMHO [/i] be built to go back in time.

As a matter of fact, you are the one to say. But you need to construct a proof. It is impossible for you to construct a proof, until you define what is meant by saying "travel through time."

One such argument, might be that the location of the center of mass of the universe would instantaneously change, which is impossible.

Regards

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Explain what I meant about what?

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Why "You (i) am the one to say........."

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Why "You (i) am the one to say........."

Oh... why should something so obvious astonish you?

Here is why, because you are as good as anyone else out there, that's why you would be the one to say.

Regards

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yeh, i was just pointing out what could be conseved a flaw in your argument, allthough i didnt belive it was a flaw myself.

Im just being the High School Physics teacher, we've all had.

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yeh' date=' i was just pointing out what could be conseved a flaw in your argument, allthough i didnt belive it was a flaw myself.

Im just being the High School Physics teacher, we've all had.[/quote']

Well you know...

There are so many ways to prove that time travel is impossible, just pick one. To me this is just a dumb question, but it is one that can be answered so answer it.

Oh why me, lets see...

If you were to travel into the past, that supposes that right now, all the material in the past is located somewhere, and hasn't ceased to exist. Because that is why you can get to it, it's still around. It still exists. Therefore it is somewhere. But to exist means to be in the current moment in time, therefore matter which existed in the past doesn't exist now, whence you have reached a contradiction.

The conclusion is that material in the past doesn't exist anywhere in the three dimensional space of reality.

The same goes for all moments in time in the future.

So the argument I gave you is spatial. In other words, in order to travel into the past, material in the past must exist somewhere in the present. It exists nowhere in the present, for it would lie on top of matter which is here in the present, which is really just matter from the past already in the present, which is what is here, but the configuration of it is different now.

Regards

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I agree with you totally. I am however disturbed by how many people think that time travel is possible.

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I agree with you totally. I am however disturbed by how many people think that time travel is possible.

It depends upon what they think time travel is.

We can always move one moment in time, into the future. But once we are there it becomes the present.

It doesn't matter what people think. Let them think what they want, that doesn't alter what is true. Reality is objective not subjective.

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

But, this is a question which physics is supposed to be able to answer.

The laws of physics involve conservation laws.

Conservation of energy.

Conservation of matter.

Conservation of charge.

Conservation of linear momentum.

Conservation of angular momentum.

Conservation of Baryon number.

The list goes on and on.

At least one of them is true.

This is no argument, but as I say there are so many to choose from, all leading to the same conclusion.

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maybe not time travel as in H.G.Wells the Time Machine. but there may be a way to use black holes. once you have desablized gravity to a point by using a powerful Electromagnet, and a fission reactor using the gasses that surround the ship. if this Theory is correct then we may be able use black holes for travel. also using the reactor to power the ship.

signed,

B. Bourget

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the question that dwells on almost any physics professor, of philosopher's mind is "Is time travel possible?"

No it doesn't. Hell, I bet you don't even go through the day spending, excuse me, an inordinate amount of time on the subject. On topic, there's more reason to believe in God than time travel. At least the possibility of the divine doesn't require a revision of our perception of entropic progression along the time axis. That said, I checked uncertain.

Rev Prez

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Well, it took me a few seconds to truly graps just what Johnny was saying, and then it hit me. What he's talking about is that since you don't know where the matter that existed in the past was (or really, if it exists at all) how could you travel to it? You can't. But that's assuming that you can't regard the material in the present to be later forms of material in the past. I'm not entirely sure what concept I'm trying to extrapolate from this thing I call my brain, but it makes a fragile sort of sense to my mind. Give me a little more time to thing about it, and I'll elaborate.

Whos to say (me) that the conservation of matter is not a concept which takens into account time and time travel?

Zeo, you mention a 'device'; well really you answered your own question. A device cannot IMHO be built to go back in time

When did I say this? I'm sure I did, but I've forgotten a lot of what I've written down here, so I'm a little in the dark as to when I said it.

Anyway, something me and a friend were talking about: Getting away from the conservation of mass, let's go back into deeper details. Such as the actions you could make in the past that would affect the future. My conclusion is that you cannot travel to the past intending to do anything if the intent arose before you actually traveled back. In fact, you can't intend to do ANYTHING until you actually get to the past. That would eliminate the possibility of a paradox created by traveling back to change something, time continuing from the point of change, and then reaching the point where you traveled back, but you don't go back because you don't need to change it anymore, hence, it's never changed, hence, paradox.

Hard to follow, I know.

This is assuming that you could go back in the first place.

Who's to say that the conservation of matter/energy is uniform throughout the entire universe?

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Conservation of matter.

Regards

The conservation argument does not hold.

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

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The laws of physics involve conservation laws.

Conservation of energy.

Conservation of matter.

Conservation of charge.

Conservation of linear momentum.

Conservation of angular momentum.

Conservation of Baryon number.

And all conservation laws stem from symmetries. So? What symmetry do you violate by going backward in time?

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Apparently, assuming that we are able to send something back through time (say, a rock for example), that would be putting new matter into the past in which the same matter had already existed (in some form or other). Hence, NEW matter, just suddenly appearing out of nowhere . . . Johnny's argument might not be complete, but he still has the right idea, if he was going with it . . . but Sayo's right, it just doesn't hold out.

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And all conservation laws stem from symmetries. So? What symmetry do you violate by going backward in time?

All of them?

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Apparently, assuming that we are able to send something back through time (say, a rock for example), that would be putting new matter into the past in which the same matter had already existed (in some form or other). Hence, NEW matter, just suddenly appearing out of nowhere . . . Johnny's argument might not be complete, but he still has the right idea, if he was going with it . . . but Sayo's right, it just doesn't hold out.

Yes zeo, that was one of several ways to realize you cant travel into the past. You throw a rock back in time, just a little bit, and you have new matter appear from out of nowhere, because that rock is there already, just a wee bit younger.

So this is violation of conservation of matter.

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But then, what does Sayonara mean by saying that they can be worked around?

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All of them?

As long as there is a continuous symmetry transformation, yes

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But then, what does Sayonara mean by saying that they can be worked around?

he was joshing you

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As long as there is a continuous symmetry transformation, yes

I've read about Emmy Noether before. What is exactly is a continuous symmetry transformation? It didn't say clearly there. I'm still looking it over though.

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

[/quote']

what exactly do you mean by this

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