Time Travel

[michel123456]

Can you give backup for the idea that "the present is present, i.e., now everywhere", for example, a physics theory consistent with relativity's confirmed predictions and presentism? I would be very interested in looking at that theory.

(...)

The Pencil Universe (in this Forum Trash Can )

Edited June 5, 2011 by michel123456

[Iggy]

The Pencil Universe (in this Forum Trash Can )

 

Yeah, I remember that

 

I remember we talked about it in a thread called "can we see it" and I did (or we did) bring up presentism in that thread. I also remember saying that I didn't think your idea would be consistent with special relativity... I mean... I asked Owl for a "physics theory consistent with relativity's confirmed predictions and presentism" and I think your idea would indeed be consistent with presentism, but not the confirmed predictions of relativity. In fact, I think I remember saying that exactly in the thread. Let me find that...

 

...the moving-object-through-spacetime concept... I think we can agree that the ['pencil' objects] share a present--that is to say, they are both always in the present. According to this view, nothing exists that is not in their present...

 

[...but...]

 

 

The blue and red sheets are the present instant of [the blue and red] observer. Each is skewed into the past and future of the other. The colorado.edu webpage explains:http://casa.colorado.edu/~ajsh/sr/centre.html. If you click next at the bottom of the page it shows an experiment where light interacts with mirrors that are not all in the same present. This is how the speed of light is preserved as an invariant in four dimensional spacetime essentially confirming that things exist for one observer which are in the past and future of the other observer.

 

What I was going for might be better shown here:

 

ned wright's tutorial.

 

In Galilean relativity everything exists in one present -- one horizontal slice. But, in special relativity (the image on the right) the two observers have two different present instants, each in the past and future of the other. So, we can't say that everything in the present is all that exists -- not in Minkowski spacetime with more than one reference frame.

Yeah -- so I agree that your idea was consistent with presentism but not that it is consistent with the observational consequences of special relativity.

 

Good reference though... I only hope I'm not contributing too much to taking the thread off topic (I'm sure I am -- sorry).

Edited June 5, 2011 by Iggy

[Tirgan]

According to quantum mechanics (at microcosm) there is a backward in time at infinitesimal level. But, in macrocosm according to H particle-paths hypothesis in my website "Hparticles.com/", the time travel to the past due to entropy problem is impossible. In other words, in our expanding universe that entropy is increasing linearly. The travel of human being to the past means that we can decrease the entropy down to the past in spatial medium that it is impossible at now.

Aperently, theoretically, with the use of wormholes and negative energy, and all that shtufff, it could be possible one day to create trips back in time.

Here is an explaination of why i dont understand how this works:

 

I would beleive that once traveled back in time, you would obviously do something that would change the path of the future. Now, in this new future, you might not creating a time machine, so you wouldn't have been able to change the past, so you would have actually created the time machine, and .... yeah.

 

Looking past this problem, I would beleive that changing the past could create either a time machine earlier, or later. Now, if we loop back to the past in either of those scenarios, we alter the past, and the time in which civilization creates the time machine would continually change. Eventually, the only possibility is that the loop continues until we have a universe in which the time machine is never discovered.

 

Looking past this looping problem, each time we would make a loop to the past, we are allowing some radiation to enter in with us. After thousands or maybe even millions of these loops (we aren't limited timewise if time keeps being "reset") there would be waay to much radiation and life would die out.

 

These problems seem pretty prominent in my eyes, but im sure that some of you out there may provide a better angle or new knowlegde on this topic to help me better understand it. A solution that i believe i have heard before, is that when traveling back in time, you actually enter a whole different parallel universe, seperate from the original one, but similar in many ways. This i believe would solve the problem, buuut how exactly would that work.... I think i have somewhat of a grasp on these concepts, but want someone to clarify.

[Marqq]

Time is change, as far as we've been able to observe. If a state (A) is changed to state (B), and later returns to a state equivalent to A (A₂), has time moved backwards? What if the path (or sequence of change) from B to A₂ was the perfect inverse of the path from A to B? Personally, I think not. I feel that even the terms 'time-dilation' and 'space-time' are overly ambiguous. Time is change, and slowing or reversing a change does not slow or move back the objective observer's wristwatch. If the universe were a DVD you were watching (objectively), rewinding it would not change the clock on your wall.

 

Does this paragraph seem illogical? It should-- if time = change, and you add 5 to change, then subtract 5 from change, you have moved time forwards and backwards. There's ambiguity in my paragraph, because I used two definitions for 'time' based on from where the time is measured. Note that in the last sentence, if the universe were a clock (or other chronometer), then indeed, rewinding the DVD would reverse time (in the DVD). Relativity is a turd like that.

 

Although I'm sure someone has come up with a different term already, I don't know it, so I'll separate the aforementioned temporal points of relativity as such:

time = outside observer time, which measures non-dilated universal time; as though measuring from a completely closed system-- immune to any dilation or tampering

tighm = time within a manipulated system; relative time to a specified observer

thyme = oops...never mind

 

Tighm is change, as far as we've been able to observe. If a state (A) is changed to state (B), and later returns to a state equivalent to A (A₂), has time moved backwards? What if the path (or sequence of change) from B to A₂ was the perfect inverse of the path from A to B? Personally, I think not.

Time travel is constant and unidirectional. Tighm travel is an absolute possibility, though extremely difficult, as it involves reversing a system of forces twice (the second reversal is needed to set change back to a positive rate of change), and providing perfect outside influence on the system (returning whatever may have escaped the system over the course of initial tighm passage).

 

Now to step a bit outside my comfort zone and allow for the possibility of perceived time-travel.

Suppose all things in the universe contain all information about their past (and future), as though each entity could be expressed as one or more non-terminating, non-repeating decimal(s), with each digit signifying energy, x/y/z placement, direction, etc. at a given interval. (sorry for the run-on sentence) Then suppose that changing an earlier digit were possible, and that doing so would influence the following digits. With all things interacting as they do, adding new matter and energy (or transforming something already existing) could effectively change the past (in reality, though, it'd be changing the present to reflect a different past).

 

I'm not explaining very well the model in my mind, and there would certainly be much more to it. The point is, with time manipulation of this sort, paradox could be avoided, because the present would be changed instantly, while the past would remain safely unchanged.

 

... in my website "Hparticles.com/"...

 

I think you forgot your dash... I googled it and found you at url removed

Edited June 26, 2011 by swansont
remove link

[36grit]

For all we know, we do time travel all the time. Our perceptions are always in the now. If you went back to the time that you were five years old then you would be five years old. Nothing would change. The world would just run the exact same course that it did and you'd be stuck in a time loop and not even know it except for occasional deja vu.

To time travel like in the movies you'd have to Isolate yourself and send everything else back in time and then figure out how to de-isolate yourself. IF we could survive as just conciousness without physical bodies it might be possible.

 

 

[IM Egdall]

For all we know, we do time travel all the time. Our perceptions are always in the now. If you went back to the time that you were five years old then you would be five years old. Nothing would change. The world would just run the exact same course that it did and you'd be stuck in a time loop and not even know it except for occasional deja vu.

To time travel like in the movies you'd have to Isolate yourself and send everything else back in time and then figure out how to de-isolate yourself. IF we could survive as just conciousness without physical bodies it might be possible.

 

 

 

We in fact do time travel all the time and we don't need a time machine to do it. One way is through motion per special relativity. Say your roommate is at home sick. You travel to work, school, or whatever in your car. Then you drive home. Your watch has run a tiny bit slower than your roommates watch because you have been in motion with respect to him. (And because it is you who has experienced acceleration, not your roommate, time has run slower only for you.) So when you return home, your arrive a tiny bit into the future. See link:

 

http://www.marksmodernphysics.com/ and click on Its Relative

 

Edited July 9, 2011 by I ME

[michel123456]

(...) So when you return home, your arrive a tiny bit into the future.

 

Oh yes? And when I give a welcome kiss to my room mate we are not in our mutual present, I am in his (her) future?