# Time travel

Discussion in 'Off-Topic' started by strantor, Dec 31, 2012.

1. ### strantor Thread Starter AAC Fanatic!

Oct 3, 2010
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This is in Off Topic because I can see the future. If I posted it in science or physics, people would be at each other's throats.

So, I watched a movie last night about time travel. Like most time travel sci-fi movies, it involved going back in time. I would like to separate science fiction from accepted science theory. I have read zero of the published works on the topic; basically all I know is what I've gleaned from what other people have said about it online.

The way I understand it (please, correct me if I'm wrong - that's what this thread is about), according to accepted scientific theory, time travel should be possible, but it should not be possible to actually go back in time. It should only be possible to proceed into the future at a different rate than "normal." The analogy I have created to describe it is as follows:

imagine 100 synchronized sky divers falling with their bodies parallel to the earth. They fall at their terminal velocity, which is equal, and can be described as the "normal" passage of time. Then one of them turns perpendicular to the earth and accelerates to a new terminal velocity which is faster than "normal" and so advances into the future ahead of the the others. This is your "time traveler." He can't reverse back up into the sky, back to where he was, as the passage of time is irreversible. He can only change the rate at which he advances into the future. He may even deploy his parachute and allow the others to catch up to him, but still cannot travel in a backward direction, only forward.

Is this close to what's described in accepted theory or do I have it all wrong? Should it be theoretically possible to go back in time?

2. ### tester272001 New Member

Aug 24, 2012
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Your example is close. The theory Einstein had was called "time dilation". The closer you get to traveling at the speed of light, time SLOWS down (for you the traveler). Those not traveling with you perceive the passage of time like normal. Scientists have taken very accurate time clocks on board aircaft and measured this variance. So it is a known phenomenon. And yes you cannot travel back unless you could generate some time curvature in space-time. (science fiction right now). Carl Sagan and many other have written about this topic. Steve Hawkins too (I believe). It is facinating stuff.

3. ### maxpower097 Well-Known Member

Feb 20, 2009
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Check out Looper.While there are inconsistansies with the story most people who study that say if its possible its gonna be with in your own lifetime, so QuantumLeap and Looper got that right. As far as time travel you can only travel ones own lifetime.

4. ### THE_RB AAC Fanatic!

Feb 11, 2008
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I'm with Strantor I think it will not be possible (ever) to physically send mass (and probably energy) back in time, it gets way too messy.

I think they might one day be able to OBSERVE previous points in time, but not to "go back".

5. ### maxpower097 Well-Known Member

Feb 20, 2009
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I don't think it will ever be physically possible to do, but I think it may be theoretically able to do.

6. ### strantor Thread Starter AAC Fanatic!

Oct 3, 2010
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Looper is the movie in question. Inconsistencies, I tend to agree, but not sure since the whole premise seems off to me. Time travel, as in going back in time, if it were possible in my life time, Wouldn't we have already met a time traveler? Actually anyone at any time in history should have met a time traveler (other than eloi cole) if it were possible. Unless they were cautious observers who were adept at not causing the "butterfly effect."

7. ### magnet18 Senior Member

Dec 22, 2010
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I think it may someday be THEORETICALLY POSSIBLE to send mass and/or energy back in time, (no idea how but once teleportation becomes theoretically possible it may open some doors), but because of the fact that we wont know the possible consequences, people will not be allowed to go back in time as "time travelers"
It would get far, far too messy
The sending back of tiny undetectable observation devices, however, or somehow otherwise observing the past, is more plausible.

Back to strantors original topic, yes, we currently have the technology to send people forward in time, simply by making them go really, really fast.
Someday we might be able to make a machine that can accelerate a human fast enough to essentially jump or throw them years into the future in a matter of seconds or minutes from their perspective, but you are correct in that Einsteins laws do not allow for travel backwards in time. If my understanding is correct, once you move the speed of light, you stop moving through time, and everything else continues.
This stuff hurts the brain.

I think that since it is possible to age slower than everything else with time dialation, the inverse might also be possible. That is everything else ages slower than you, and you can essentially "stop" time. This would somehow require un-accelerating you, or rather accelerating the entire universe excepting you.

ALSO
I saw looper, pretty sure they weren't limited to their own lifetimes, it said that nowhere, that was just quantum leap.
I have no idea why you would only be ale to travel within your own lifetime, quantum leap was based on the now discredited string theory

however looper did give me the idea for a self collapsing paradox, in which paradoxes are impossible because as soon as the paradox is created the person no longer needs to create the paradox, and the entire timeline would just collapse, bringing the person back to before they created the paradox, and the cycle repeats until they decide not to create the paradox (think Schrodinger)

Last edited: Jan 1, 2013
8. ### maxpower097 Well-Known Member

Feb 20, 2009
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They address this in Looper, where she finds her kids DOB and Hospital code on the map and she peppers him with salt rock. She shoots him and puts it to his face and ask "Why the hell do you have these numbers" He then goes on with his standard "Time travel hasn't been invented yet but in 30 years it will be and will immediately be banned. Only the highest of organized crime use it to dispose of bodies since its too hard to do 30 years in the future with trackers and stuff." She then cuts him off and says so you mean your a LOOPER!?!?! He responds you know what we do? So the movie gives the thought that the average citizen knows that loopers and time travel exist but only one way. Also remember to take the movie as not alternate timelines but different possiblities that can exist. And as that timeline becomes more likely to happen his memories would get stronger and vice versa.

9. ### strantor Thread Starter AAC Fanatic!

Oct 3, 2010
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The biggest hole I saw in the movie was that things that happened to the "present day" character also happened to the "future" character. Like the carving messages in the arm and cutting fingers and feet off, etc.

If a guy traveled back in time 30 years, he just exited reality and entered a new reality. There is no longer any timeline leading from the present day guy to the future guy. This can only be an alternate timeline the way I see it, no room for "different possibilities."

Even if things were to happen as they show in the movie, the part about the guy's fingers disappearing one at a time, followed by feet, and then face, etc. is totally out. In order for his finger to be cut off in present day and reflect in the future character, he would have to live a whole life with the finger detached. He would have had to make it out of the scenario alive minus one finger. But he didn't; he had all his fingers and feet cut off and then killed within a span of 5 min. The future character should have just ceased to be, without all the fanfare. But, I still maintain that he would remain alive since his timeline is not tied to the present day character. He is essentially a totally different person, with the same DNA.

I feel a little silly discussing the fictional science behind a science fiction movie, but at the same time I enjoy it. You can't see my face, so I'm not embarrassed. My guilty pleasure. Now I know what it feels like to be a trekkie.

10. ### magnet18 Senior Member

Dec 22, 2010
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Hey now... watchit...

strantor likes this.
11. ### R!f@@ AAC Fanatic!

Apr 2, 2009
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Time travel is possible but not the way you think.

As for a another human going through time, I say no, never again.

There are some science facts that is true but it can never be in practical.

end of topic.

12. ### maxpower097 Well-Known Member

Feb 20, 2009
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Yah I liked that scene but it didn't add up. Also consider many of these were books converted to movies or incredibly long screenplays made into a movie. So lots of stuff gets cut sometimes even if its crucial to the story line.

By far my favorite time travel is Star Trek! And to go back in time for the 09 movie was brilliant.

Feb 20, 2009
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14. ### takao21203 Distinguished Member

Apr 28, 2012
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1. The universe as big as it really is, still remains finite state.
2. Inside the sun's core, time actually stands still. Interesting thought.
3. All of humanity is loosely connected into a big matrix. This is where all dreams, visions, ideas and hopes come from.

So actually, the future as it evolves is partially already known.

Existing patterns will transform into other patterns which are somehow predictable.

Sometimes, visions will occur not to be true.
Sometimes, they will actually turn out to become the truth.

The timespan for this is some days to some months.

4. Time as we know it only exists for living beings. Once you are death, you can travel all the way back on the timetrack.

Because of the implications which a backwards time travel would cause, it is actually not possible for living beings to travel back in time.

5. At some finite point in the future, everything will turn into a singularity made from lead. Lead neither can fusion or fission. If it become a large enough singularity, with only lead left, it will suddenly break into hydrogen. You can imagine the explosion will be unimagineably powerful.

Think of these Mandelbrot fractals. Time is just another dimension. It is all self-contained. So not even one single photon can escape.

There are maybe more dimensions than 4. But ordinary humans are not able to imagine. They even find it hard really to get a good feeling that the earth is round, and people don't fall off.

6. How would it be if the moon is brought to earth, and anchored, so it just touches the earth?

-How about gravity on the top of the moon ball?
-How about atmosphere? Would it spread all over the moon, just a little, or same as on earth?

You will find answering these questions properly difficult enough, let alone the question how it can be anchored to earth in practical matters.

15. ### strantor Thread Starter AAC Fanatic!

Oct 3, 2010
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WTF are you talking about takao?

Apr 28, 2012
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17. ### bountyhunter Well-Known Member

Sep 7, 2009
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Nope. It's malarkey. I think it was Stephen Hawkings who put forth the most compelling "proof" that time travel is impossible. If it was possible, it would have already happened since at some point technology created it, time travelers would have gone back throughout history.

18. ### loosewire AAC Fanatic!

Apr 25, 2008
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You Guys are so wrong ,how would you dare to be so careless about time,

something you know so little about. I touched time.

19. ### tshuck Well-Known Member

Oct 18, 2012
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Absence of proof is not proof of absence...

Even if humanity, at a point in our existence, were to create the technology to move backward in time, we(people in the past relative to the traveler) might not be able to determine if a person was, indeed from the future as a person coming back, would, possibly, break from the course of reality that led to the future person's version of the future, meaning that the person could not have come from the future as that future would never be attainable from within the current reality. At which point, any information a time-traveler would have would only be relevant for events occurring before the split in realities, the same as everyone else... If they were to start talking of the future, it would be of one that would never exist, so it would be easy to label them as insane.

20. ### loosewire AAC Fanatic!

Apr 25, 2008
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Time is now,time is the past,you don't if you will be here to to post about time

again.