Time Travel Question

[scotthm]

You miss my point. Any matter that is "created" in the past is "destroyed" simultaneously in the future. Thus balance is maintained. The energy thing was just a parallel observation.

I must be missing something, because I don't understand what you're talking about.

If I have a dollar at noon, and at 1 pm I send it back half an hour, then at 12:30 pm I'll have two dollars. At 1 pm I'll still have two dollars. At 2 pm I'll still have two dollars (Assume I'm very frugal.) For the rest of my life I'll keep these two dollar bills. Which 'future' dollar bill was destroyed?

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[Gepard]

If I have a dollar at noon, and at 1 pm I send it back half an hour, then at 12:30 pm I'll have two dollars. At 1 pm I'll still have two dollars. At 2 pm I'll still have two dollars (Assume I'm very frugal.) For the rest of my life I'll keep these two dollar bills. Which 'future' dollar bill was destroyed?

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No, after 1 pm, you'll only have one dollar again, because in order to have two dollars between 12:30 and 1, you must send one of the bills back in time at 1pm. You can't not send one back at 1, because then you'll never have two dollars in the first place. No matter how you slice it, you can't use time travel to create an extra dollar bill that you can keep for the rest of your life.

 

[Lindley]

I suppose you could deal with the "send yourself back, then destroy the time machine" problem by looking at matter being created/destroyed on the multiverse level, in addition to over the entire timeline. In that case time travel would amount to reality hopping, really.

 

[scotthm]

No, after 1 pm, you'll only have one dollar again, because in order to have two dollars between 12:30 and 1, you must send one of the bills back in time at 1pm.

And who's going to make me do that? I've decided that I like having two dollars better than one.

What you seem to be saying is that if backwards time travel is possible, then the future is already 'written in stone'. Well, if the future is written then the past must be also (because it used to be the future), so therefore backwards time travel would be impossible.

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[The Borg Queen]

Ah, but matter can be created out of energy, thus demonstrating that the "matter cannot be created or destroyed" mantra is only true if you look at it in a wider context. Given that, I see no reason why matter moving between two times would be problematic; it's not being created or destroyed in the context of the entire timeline.

What energy was used to create this extra matter (you)? The energy you used to power your time machine still exists in the earlier time, and now so does the duplicate you, so you have both the original energy and the new matter that's been created. The two yous then destroy the time machine when you realize how dangerous it is, and go on about your merry way. You've just added matter to the universe, at no net cost!

So... time travel into the past is not possible.

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You miss my point. Any matter that is "created" in the past is "destroyed" simultaneously in the future. Thus balance is maintained. The energy thing was just a parallel observation.

No different than moving matter around in our usual 3 dimensions, really. Just a bit more loopy.

Destroying the time machine you used would be something you'd only do if you were really, really angry at the universe. Or wanted to see what happened. Either way, probably not good.

I think I see what you mean, like in the same way (at the quantum level) that a particle and anti-particle can spontaneously pop into existence for a fraction of a second before colliding again and cease to exist.

I think the energy to create that particle of matter/anti-matter is transformed from zero-point-energy or something, I'm not completely sure...

The amount of energy needed to create something as superhuge as a whole person must be unimaginable, though.

 

[Broccoli]

I think my brain fell out while reading this thread.

 

[Gepard]

And who's going to make me do that? I've decided that I like having two dollars better than one.

What you seem to be saying is that if backwards time travel is possible, then the future is already 'written in stone'. Well, if the future is written then the past must be also (because it used to be the future), so therefore backwards time travel would be impossible.

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Yes. If you've gotten a message form the future, then that future--or at least the part of it that you have observed, must happen, otherwise it would not be there in the future for you to observe it. I see it as being like Schrödinger's Box: as long as it remains unmeasured, the future is indeterminate; as time moves forward, we "measure" the future by becoming it, and the quantum waveforms collapse into one coherent "now." If you have a time machine, you can cheat a bit and look forward in time, but by so doing, you measure the future, collapsing the waveforms between "now" and "then," much like opening the box forces the cat to become either alive or dead when it wasn't either before you opened the box. So in that sense, with time travel, the future has "already" happened...otherwise, there wouldn't be a future there for you to travel back from!

As to the dollar bills, I think your miserliness would prevent you from ever getting two dollars, because you would be unwilling to sacrifice one by sending it back in time, so you'd wait forever for a second bill to show up form the future, a bill which will never arrive because you decide(d) not to send it....

 

[Meredith]

Or time travel works, but you can never go home, you can go to the next best analouge of home in the past, but never home home.

 

[Andrew Harris]

Here's how I look at time travel: it's like any other sort of travel.

If you're going from New York to L.A., there's all sorts of possible roads you can take.

But if you travel back on one of those roads, and then go from New York to L.A. once again, using a different route, it doesn't mean the first trip never happened, or the first road is no longer there.

For that matter, it wouldn't make a difference if the second time you ended up in San Francisco. Or, didn't even go back at all.

 

[scotthm]

As to the dollar bills, I think your miserliness would prevent you from ever getting two dollars, because you would be unwilling to sacrifice one by sending it back in time, so you'd wait forever for a second bill to show up form the future, a bill which will never arrive because you decide(d) not to send it....

Oh no, I'd gladly send it back with the expectation of instantly ending up with two copies of my dollar in my pocket.

Or time travel works, but you can never go home, you can go to the next best analouge of home in the past, but never home home.

But if there was some mechanism to prevent you from "going home", why wouldn't there be some mechanism to prevent you from travelling into the past at all?

Here's how I look at time travel: it's like any other sort of travel.

Except that the time 'dimension' is unlike any other known dimension. This is obvious in the fact that we're having to just imagine ways of travelling freely in time, while we naturally are able to travel freely in three spacial dimensions.

Perhaps time doesn't flow at all, and all of eternity, from beginning to end exists simultaneously, unchanging forever. Perhaps it's only our conscious thoughts that 'move' through time, and the same thing that makes consciousness possible allows for movement in only one direction.

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[Andrew Harris]

Here's how I look at time travel: it's like any other sort of travel.

Except that the time 'dimension' is unlike any other known dimension. This is obvious in the fact that we're having to just imagine ways of travelling freely in time, while we naturally are able to travel freely in three spacial dimensions.

Actually, I think time is a dimension exactly like other known dimensions. We just perceive it differently; that doesn't change the nature of the dimension itself.

And, I don't think we're able to "naturally" travel freely through three-dimensional space at all. We're all moving through space at a direction and velocity that we can't control--we're just anchored to the Earth as we do it. (Even in out in space, it's happening, we're just not anchored.)

It's just a trick of perception to think that we actually have all that much control over it--and, in truth, when considering how fast we're actually moving while anchored to the Earth, the small shifts in our exact Earthbound location that occur as we maneuver through our day are probably scientifically and mathematically insignificant.

The only real difference I see is that while we are also all traveling through time--we're just doing it all in the same direction, and at the same speed--we don't have nearly as much control over it. Astronauts out in space actually move at a slightly different speed through time than the rest of us, but it's much more difficult to accomplish that than to simply get up from your chair and walk to the fridge.

 

[scotthm]

Actually, I think time is a dimension exactly like other known dimensions. We just perceive it differently; that doesn't change the nature of the dimension itself.

If our perception of it is different, then there must be something different about it, otherwise our senses wouldn't be able to distinguish between it and other dimensions.

And, I don't think we're able to "naturally" travel freely through three-dimensional space at all. We're all moving through space at a direction and velocity that we can't control--we're just anchored to the Earth as we do it.

I can voluntarily move my body in three dimensions, and am not 'anchored' to the Earth. I am 'attracted' to the Earth, but not anchored.

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[Andrew Harris]

Actually, I think time is a dimension exactly like other known dimensions. We just perceive it differently; that doesn't change the nature of the dimension itself.

If our perception of it is different, then there must be something different about it, otherwise our senses wouldn't be able to distinguish between it and other dimensions.

Hmm... I don't think that's the case at all. If I hold up a coin, you can look at it from the edge (thin) or from the front (round). It looks completely different either way, but it's the exact same coin--nothing "different about it".

In fact, if you look at it from behind, it'll look round but have a completely different design on it--again, though, still the same coin. So, just because we perceive time differently than space doesn't have anything to do with whether the fourth dimension is actually inherently different than the other three.

And, I don't think we're able to "naturally" travel freely through three-dimensional space at all. We're all moving through space at a direction and velocity that we can't control--we're just anchored to the Earth as we do it.

I can voluntarily move my body in three dimensions, and am not 'anchored' to the Earth. I am 'attracted' to the Earth, but not anchored.

Well, OK--anchored, attracted, call it what you want. The point is that your ability to control your movements through three dimensions is miniscule compared to the amount you're actually moving through three dimensions.

The same with time: you can change your movement through time only very slightly (such as by becoming an astronaut and orbiting the Earth for a couple of months), but it's pretty inconsequential compared to your actual movement through time, over which you have no control.

 

[think]

I liked the "Time Trax" series they just took a hit of something?- and went to the past., I have probably gone too far into the past to really make sense of what my future used to be like ., but it is so quantum like these networks of discussions and threads.,

I will loop back, at some point, to see if anything changes., maybe