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Teleportation (like a StarGate) and Time travel

  1. Apr 24, 2004 #1
    I'm not sure if this is the right place to put this thread but...

    Are they possible? I have been watching alot of StarGate SG-1 and other movies that deal with these two issues. First I want to know if matter can be effectively molecularized and reassambled in its original form (anything - from a chair to a human), even if it's only a few feet across a room? And then (I think Einstien said it was possible) I want to know if time travel is possible and the (non-mathematical only explanatory part) theory of how it's possible. Do these two phenomenon take place in the 4th dimention? If so, how? I would appreciate any help.
  2. jcsd
  3. Apr 24, 2004 #2
    You might consider the amount of entropy that changes in the process. This might give you an idea of how much energy would be required to reassemble it.
  4. Apr 24, 2004 #3


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    You probably already know about how master can be converted to energy via Einstein's famous equation, e=mc2. This is the means by which nuclear weapons generate an explosion. A tiny amount of the hydrogen in the center of an H-bomb is converted from matter to energy in these few small drops of hydrogen release all that blast. Considering the mass of a human body, imagine the amount of energy that would be released if one work converted entirely to energy. All of this energy would have to be contained in control.

    Wormholes are not out of the question, according to our current understanding of the dynamics of space-time. However, for a wormhole to exist and stay open long enough for anything to pass through would require the presence of a very exotic form of energy known as "negative energy". Negative energy can only exist in a system containing a greater amount of positive or "ordinary" energy. The amount of negative energy needed to hold a wormhole open is a direct function of the size of the whole. To open and maintain a wormhole large enough for a person to pass through would require more energy than one would get by converting all the mass of all for matter in the universe.

    But of course, these are mere problems of power requirement. The concepts are possible, if we can find some way around their copious demands for power.
  5. Apr 25, 2004 #4
    The reassembly bit is a trifle tricky. :smile:

    "Molecularized" - broken into component molecules - is not really the solution, since one would need to transport the molecules reliably (sequentially?) from one location to another. Tricky.

    Probably more effective to try to analyze the physical construction of an object into information, transport the information, then construct a duplicate of the original using the information. Still tricky, but perhaps not as tricky.

    Then, of course, you would still have the original to deal with....

    It's the old Star Trek problem: Just because you have dematerialized something and reconstructed it at another location does not necessarily mean that you have the same thing - rather, in almost every circumstance, you have only a copy of the thing.

    By and large, I do not believe that "teleportation" will ever work - at least, not in any meaningful way - and especially not in a way people will trust. - and not using known science or imaginable technology.

    The main reason that we want teleportation is because we are in an awful hurry. We are in a hurry because we die quickly, and because we are bored with the process. What if both of those problems could be resolved? Would we still be in such an all-fired hurry?
  6. Apr 25, 2004 #5
    Careful, this is not true. The energy from nuclear explosions is derived from the difference in binding energies between parent and daughter products in fusion / fission reactions. The hydrogen (deuterium and tritium, actually) is not converted directly to energy.
  7. Apr 26, 2004 #6


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    The mass of the hydrogen is.
  8. Apr 26, 2004 #7
    The mass of hydrogen is roughly 930 MeV, while H/D/T fusion reactions release between about 5-25 MeV (per fusion). That's over an order of magnitude difference.
  9. Apr 26, 2004 #8


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    That's what I said: "a tiny amount":biggrin:

    It is possible, however, to convert nearly all the mass of a certain bit of matter into energy, through an antimatter reaction. But the important thing is that even if one converted all the mass in the universe into energy, there would still not be enough to form a system in which could exist the amount of negative energy needed to form a stable wormhole large enough for space travellers to go through.
  10. Jul 9, 2004 #9
    Getting back to your questions cyberice:

    The others have already sufficiently answered your question about teleportation. Demolecularization (if that's a word) isn't the answer. Unfortunately the problem with reconstructing a copy of the original subject, or matter-energy-matter conversion, is that you need to know a considerable amount about every particle in the original subject. This is where it gets tricky: due to something called quantum uncertainty, predicted by quantum mechanics, you can never know everything about a particle. For example, the more you know about its position, the less you can know about its velocity. This has to do with the unavoidable interference caused by observation. And unless you know exactly how fast a particle is moving, and exactly where it is when you take this observation, building the duplicate or reconstructing the original in the matter-energy-matter conversion, is impossible. Then there's also the core of quantum mechanics itself: everything is probability. Even if you could know completely both the position and velocity of a particle, you can only determine the probability of where it will be in a few seconds. You can never know for sure. Now I seem to recall reading somewhere that a single photon had been "teleported" and that the information was gained through a process called entanglement. Photon A is the one you want to teleport. Photon B is in the place where you want to teleport it to. Now we introduce Photon C which is entangled with photon A. Photon A is destroyed in the process and photon C now contains all the information about it. Somehow the information contained in photon C is then transferred to photon B, which becomes a duplicate of photon A. The point is, even if teleportation ever is possible, it will no matter what require the destruction of the original.

    Time travel
    According to Einstein's theory of Special Relativity, as you increase your speed relative to another observer, that observer will note time as passing more slowly for you than for them. There is an extremely good article at http://science.howstuffworks.com/relativity.htm that explains why this happens and does so in very easy to understand, non mathematical terms, if you would like to know more about it. Once you accept time dilation as it's called (which actually refers to what the moving observer sees), then you can see how it can be used to "travel" to the future. If you were to blast off in a space ship and accelerate to 0.9999999999999 the speed of light, for every 1 second that passes for you, about 2236068 seconds would pass for everyone back on earth (to anyone who knows how to use the Lorentz equations, yes I did calculate this, Cyberice asked for the math to be left out). If you maintained this speed for 24 hours, over 6,000 years would pass back on earth. You could then return to earth having hardly aged but millenia after you left, effectively "travelling" to the future. Unfortunately, reaching such fantastic speeds is no easy task. Another relativistic effect is that as you increase your mass, more and more energy is required to accelerate. This number becomes infinite at the speed of light (the Universe imposes many contraints making accelerating to the speed of light impossible). Particles in atom smashers are accelerated to speeds comparative to the one I mentioned, but accelerated a space ship to that speed would be quite a feat indeed. Still, it's possible. Time travel to the past is a different matter. It's not simply a matter of travelling faster than light (not only is this impossible, but plugging such a value into Einstein's equation yield's an imaginary number, as opposed to the negative number that would suggest time reversal). There are possibilities though. There are objects called cosmic strings, their existence is purely theoretical but if they do exist they are highly concentrated strings of energy, remnants of the Big Bang, that are thinner than a nucleus of an atom but several million kilometres long. Two of these strings circling each other would warp spacetime (now we're dealing with Einstein's Theory of General Relativity) so significantly, that spaceship flying around them could theoretically arrive back at it's starting point before it even left! Again, the existence of these strings is purely mathematical. Still, it is possible. Special relativity says that events that are simultaneous in one reference frame aren't necessarily simultaneous in another (see the article I mentioned). That means one observer could see an event happen and it's in their past, while it has yet to happen for another observer, it's in their future. This suggests that what we call the past and future are forever frozen in spacetime and the present is just our fleeting impression of the Universe as it is as we hurdle through time. If that's the case, the past and future are always there, always part of the Universe, and it's only accessing them that's the question. Perhaps the methods I suggested are the ways of going about this.

    Teleportation and time travel are definitely on the cutting edge of physics. They may slowly move from the realm of science fiction to solid science, or they may remain idle fantasies of the human mind. Time will tell.

    Hope that helps!
  11. Jul 10, 2004 #10
    Any article that I've seen on teleportation through entanglement, discounts faster that light transmission of information, I assume to rebuild something information is required so it would not seem to work , at least that way.
  12. Jul 10, 2004 #11
    If you really did deconstuct someone and then rebuild them (or someone just like them) at another location. Would that be the same person or just a copy of the original?
  13. Jul 10, 2004 #12


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    The answer depends upon what consciousness is. If it's entirely a physical process, and the reconstruction accurately reproduces that process, then it's the same person. If consciousness is some mystical extra-physical thing, then there's no guarantee the new body would possess it.
  14. Jul 10, 2004 #13


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    However, if consciousness is an extra-physical thing, then it would seem likely that this phenominon, being free of the constraints of physical law, would find its way to the body with which it is associated far more easily than the body itself translates from place to place.
  15. Jul 11, 2004 #14


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    "It would seem..." Would you trust this if it was you who were to be teleported? I sure wouldn't.

    Actually when they get up to teleporting bacteria, that will be another test of whether there is a separate "life force" or not. Does the teleported bug arrive alive or dead.
  16. Jan 19, 2010 #15
    Question Time Travel Like on Star Gate SG1 the people are demoleculerized to what degree?

    Because if they are turned to energy and then transported to the other gate then reassembled the worm hole wouldn't have to be any bigger then a pin hole!!! Now if they were just demoleculerized to there basic atoms the worm hole would only have to be as big as the biggest atom then the rest of the atoms would just follow the big atom!!
  17. Jan 19, 2010 #16
    I'm going to step aside on the teleportation issue and just go to that old standby... the Closed Time-like Curve. Traveling faster than c in your own Frame = Time Travel. Same thing. If you travel 1 billion ly in a moment, no matter how you go about it, you're breaking causality, and opening the possiblity that CTCs will be created.

    Besides, "wormhole" is an ambiguous term. Do you mean an Einstein-Rosen Bridge? That is just one instance of a wormhole, and not a traversable one. A hypothetical ring-singularity with a double Event Horizon? See previous paragraph.

    It doesn't matter if you use the curvature of spacetime, or a fictional rocket... FTL travel leads to the possibility that the laws of physics will not appear to be the same for all observers, and causality goes out the window (see Hawking's "Race on Alpha Centauri" example). If you observe event A from 1 billion ly away from your initial Frame, which you reached at a speed greater than c than Event A might be an event for which you ALREADY KNOW THE OUTCOME. Some believe this is entirely possible in a universe which contains the negative curvature needed for a stable ERB-type wormhole... but that's not our universe now or at any point in its known history.

    People discount FTL transmission of "Information" (the term of art) because it is the same as time travel.
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