Seriously thoughtful Is Time Travel possible

[HarryT]

Originally Posted by pilotbob

Um... ok, isn't the first question, is there such a thing as a worm hole?

BOb

The physics of black holes appear to suggest so, yes. Whether you could actually transit one without being spewed out of the other end as a cloud of subatomic particles is, however, a different question.

[Over]

Originally Posted by ahammer

there would only be two of your if you come backfore you go back to the past however if you overshot the time you come back by a few sec late there would not be

That's a good point, but only if it goes both ways. Just like there's no YOU from the point you travel to the past, there should be no YOU until the point you travel back too, because there aren't two YOU nor the mass/actions are "recorded" somehow/somewhere. Unless you consider alternative universes, where there is one YOU in the past and multiple YOU in the future (as the future is uncertain, so there would be many different probable YOU). But in that case, the problem in my previous post remains.

terms like present are based on what you see if you came back jumped 5 mins from now would you realy not call that the present. remeber that time is not even moving at the same rate base on how fast you are going. ie. from wikipeda on gps.

One thing is the real time elapsed, another is how fast a clock ticks. One thing is time, another is an instrument. Or am I missing something?

[krisk]

Originally Posted by HarryT

The physics of black holes appear to suggest so, yes. Whether you could actually transit one without being spewed out of the other end as a cloud of subatomic particles is, however, a different question.

I have an ex I will volunteer as a test subject!

[ahammer]

Originally Posted by Over

That's a good point, but only if it goes both ways. Just like there's no YOU from the point you travel to the past, there should be no YOU until the point you travel back too, because there aren't two YOU nor the mass/actions are "recorded" somehow/somewhere. Unless you consider alternative universes, where there is one YOU in the past and multiple YOU in the future (as the future is uncertain, so there would be many different probable YOU). But in that case, the problem in my previous post remains.

One thing is the real time elapsed, another is how fast a clock ticks. One thing is time, another is an instrument. Or am I missing something?

1)wonder out the u would handle the fact that you have missing mass(and/or energy.) even with muti u you still have missing mass. hmm

2)you have to change the time of the clock base on the fact that how long a sec is when you moving as fast as the sat our. otherwize you would end up 100 miles off on your gps unit

[Over]

Originally Posted by ahammer

1)wonder out the u would handle the fact that you have missing mass(and/or energy.) even with muti u you still have missing mass. hmm

2)you have to change the time of the clock base on the fact that how long a sec is when you moving as fast as the sat our. otherwize you would end up 100 miles off on your gps unit

Once again, you're talking about a measurement, not time itself. If a second takes longer here than in orbit, doesn't mean time is faster here than in orbit. Just your perception (or your instruments') of time.

[Steven Lyle Jordan]

I would not be concerned about the YOU paradox... after all, you are made up of atomic and sub-atomic particles that are not the same from moment to moment, and so the two "you"s are never identical... therefore there is no real paradox, absolutely no physical harm would be caused by their being two of "you" in one place at the same time, you won't touch each other and create an explosion or negate time or anything, because intrinsically speaking, you are two different things that only happen to look alike.

If anything, the laws of conservation of energy would be affected (you just stole energy from the future, and input extra energy into the past), but it would be so miniscule on the grand scale of things as to be unimportant... unless, of course, you inadvertently created a "time loop" that constantly fed energy from the future into the past, thereby causing an energy imbalance that would probably overwhelm and explode the space-time continuum at that point in the past...

But if you did that, there would be no future to send energy back from, so it obviously never happened, and never will...

(Hmph. Serious thread, indeed.)

[pilotbob]

Originally Posted by Steve Jordan

and so the two "you"s are never identical... therefore there is no real paradox, absolutely no physical harm would be caused by their being two of "you" in one place at the same time, you won't touch each other and create an explosion or negate time or anything.

I always thought that two particles of matter can not occupy the same space at the same time. Are you saying that this isn't true?

BOb

[Steven Lyle Jordan]

Originally Posted by pilotbob

I always thought that two particles of matter can not occupy the same space at the same time. Are you saying that this isn't true?

BOb

I'm saying that the human body, like everything else in the universe, is made up of particles that come and go, food that becomes energy that builds new cells while old cells die and fall off, protons and neutrons and electrons that split off and are sometimes replaced by other protons and neutrons and electrons... in other words, you are constantly in flux, and never the same collection of particles from instant to instant. So the sub-atomic particles in your right hand at noon won't be the same as the sub-atomic particles in your right hand at midnight. This means that the "you" at one instant is not identical to the "you" at any other instant.

(This actually doesn't address the bit about two identical particles occupying the same place at the same time, because even if you shook hands with an identical you (which, as I just demonstrated, you can't), your particles would be NEXT TO each other, not occupying the same place at the same time... atomic forces would keep them apart, even through the tightest handshake, and nothing would happen.)

Now, if you could go back in time and your body, every sub-atomic particle of it, came to occupy the exact position as your past self at the same instant... well, I'd call a janitor...

[ahammer]

Just your perception (or your instruments') of time

As well as how long a cell will last. how fast adams move so on.

in this case perception is reallity. if you where to move at close to the speed of light you would not age as fast as everyone else time would seem to pass normaly for you but when you got back to normal speed an hour to your could be day or week or years so on.


from wikipeda

Time dilation is the phenomenon whereby an observer finds that another's clock, which is physically identical to their own, is ticking at a slower rate as measured by their own clock. This is often interpreted as time "slowing down" for the other clock, but that is only true in the context of the observer's frame of reference. Locally (i.e., from the perspective of any observer within the same frame of reference, without reference to another frame of reference), time always passes at the same rate. The time dilation phenomenon applies to any process that manifests change over time.

wonder what affect not having the speed of light seeming to not being a set number like we thoght will have on this all

[Over]

Originally Posted by ahammer

As well as how long a cell will last. how fast adams move so on.

in this case perception is reallity. if you where to move at close to the speed of light you would not age as fast as everyone else time would seem to pass normaly for you but when you got back to normal speed an hour to your could be day or week or years so on.

That's not time traveling. It's not jumping from point A in time to point B in time. At speed of light, the time wouldn't have the same affect to you and you wouldn't perceive it the same way as other people, but... You're still following the time constinuum.

Just like while I'm writing this, I'm traveling in time from 4:35pm to 4:37pm, passing by all those seconds in between. If I do it faster or if my cells age at another rate... That's not time traveling.

Plus, that's only toward the future. No matter the speed, you couldn't travel back in time. Continuously or jumping.

Originally Posted by Steve Jordan

I would not be concerned about the YOU paradox... after all, you are made up of atomic and sub-atomic particles that are not the same from moment to moment, and so the two "you"s are never identical... therefore there is no real paradox, absolutely no physical harm would be caused by their being two of "you" in one place at the same time, you won't touch each other and create an explosion or negate time or anything, because intrinsically speaking, you are two different things that only happen to look alike.

I didn't mind there can't be two YOU. I just meant that you can't travel back to YOUR time again, where only YOU exist. If you go to another time where there's another YOU, then you didn't really went back, did you? And you couldn't just return to your former life, as you would find anotehr YOU doing your job and wife, for example.

Once you make a jump in time, you renounce your former life. That means no time traveling tourism. :P

[bhartman36]

Neither time travel to the past nor time travel to the future seem possible, in any real sense.

If you travel to the past of this universe, you end up with time paradoxes. If you travel to the past of some other universe, you wouldn't really be accomplishing your goal. For instance, if you go back in time and kill Hitler in the alternate universe, nothing changes in your original universe. It keeps humming along apace, as if nothing had happened (because it didn't). That's not to say it would be a futile exercise. You'd still be killing the Hitler in the universe you were in, but you wouldn't be affecting the future you originally intended to affect. It would be more like tourism, or a missionary experience, than anything else, and you would never be able to get back to your own time again, meaning that if you went far enough back, no one you knew would be alive.

Time travel into the future is even more impossible. There's zero evidence that "the future" exists in the way that the past and present do. Can you "remember" (obviously using the term loosely) anything that happened to you in 2011? If the future already existed, there's no reason to believe you wouldn't be able to, the same way you remember the past and experience the present.

As others have noted, FTL travel might subjectively alter your perception of time, but time itself wouldn't be impacted in any way. You'd still be passing through it, just as if you'd locked yourself in suspended animation for the same period of time.

I sort of wish time travel to the past was possible, within one's own universe. It would be very tempting to "fix" the past. On the other hand, we all know how well that usually goes, now don't we?

[Xenophon]

Various science fiction authors have observed that a system (universe) in which it is possible to

1. Travel back in time
2. Change something
3. Return to the (possibly modified) "present"

is not stable. With all possible time travelers from the entire future available to meddle, eventually (in terms of iterations of the above actions, not "elapsed time") someone will make a change that causes time travel to not be invented. From that system state, no one will travel backwards in time and make a change... so the "time travel never invented" state is the only stable state for the system!

Xenophon

[kovidgoyal]

Originally Posted by Xenophon

Various science fiction authors have observed that a system (universe) in which it is possible to

1. Travel back in time
2. Change something
3. Return to the (possibly modified) "present"

is not stable. With all possible time travelers from the entire future available to meddle, eventually (in terms of iterations of the above actions, not "elapsed time") someone will make a change that causes time travel to not be invented. From that system state, no one will travel backwards in time and make a change... so the "time travel never invented" state is the only stable state for the system!

Xenophon

A time traveler might well change the state of the future to one where time travelling is not invented at a *particular period* of history, but to say that he will change it to a state where it is never invented is about the same as saying that he wipes out the solar system or some such catastrophic event. Basically the usual "kill my gradfather" paradox.

[Icarusbop]

Of course timetravel is possible, it can be done in one of two ways:

1). Borrow the TARDIS from Dr. Who (presumably you would have to arrange your own insurance)

2). But a De-Lorean, add a flux capacitor (RS stock 608-4356) and press 'GO' until you reach 88 MPH.

Everybody knows these things, why even the debate?

[Steven Lyle Jordan]

I hereby submit that this thread has no business being anywhere BUT the Lounge. Just because it is not unutterably silly, does not mean this is anything but a subject perfectly suited for any forum's lounge.