If you could travel through time, what would you do? Is it possible?

Discussion in 'Science' started by Condor060, Aug 17, 2020.

  1. Monash

    Monash Well-Known Member

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    Your basically describing the Alcubierre warp drive., but again the 'drive' implies the object inside it is isolated from the rest of the Universe and does not/cannot interact with it. So same deal as with a wormhole. It works (if it works) only because objects moving through it are isolated from the rest of the Universe during the transition from point 'A' to point 'B'.

    And just like a wormhole most physicists would argue that while using an Alcubierre drive causality rules. By this I mean you could not use a drive to create 'effect' before 'cause'. The drive will only work as long as causality is preserved.

    There are some theoretical formulations for wormholes for instance that would let you curl both ends round till they almost meet. Allowing a traveler or signal to 'appear' to arrive before it departs. Physicists would argue that attempting to do this breaches causality and this would automatically cause the wormhole in question to 'collapse' (or fail to materialize) before the traveler or message can be sent.

    Same thing for the drive. Attempts to defeat causality are always doomed to failure. You can only travel backwards in time as long as it is matched by an equal amount of distance. Travel 50 light years (LY) in space via FTL means you end up 50 years in the past (from your perspective of your departure point). Travel 50 years into the past? You end up 50 LY away in distance. No breaching causality.
     
    Last edited: Nov 9, 2020
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  2. DEFinning

    DEFinning Well-Known Member Donor

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    I'm sure it would have to be a rather complicated explanation, as your theory of a, "force greater than light," would not comport w/ physics as they are understood by anyone on the planet, which is probably why HereWeGoAgain didn't understand it from your vague, abbreviated description. I have to agree with him that it was pretty creative, though. Unlike him, however, I won't call it nonsense because this is still a speculative area, & it's not impossible that your dashed sketch could someday be shown to be analogous to some real principle, albeit accidentally, kind of like if Aristotle's theory about the 4 humours were to one day pan-out.

    And, god help me, I can actually picture what you're describing. In your interpretation, you have taken Einstein's image of time-travel as changing one's floor, in the building in which one is travelling, to a more literal level--so to speak--thereby employing, to a degree not really accounted for in conventional physics (which considers the multi-floored structure merely as an analogy), the force of gravity, leading to this idea of the past being as below, & the future, above; hence the idea of lifting or lowering, & the suggestion of the role of, "leverage." In doing this, you have now effectively separated the oneness Einstein saw as, "Space-Time," back into two distinct attributes.

    I would prefer, in trying to sell this idea, using the image of scuba-diving in the ocean. While, no matter where you swim, you are in water, nevertheless other qualities in your environment markedly change condition as one ascends or descends: the amount of light, the surrounding pressure (which even changes the gasses within one's body), the temperature; all of which lead to the various levels of ocean depth each even being populated by their own communities, types of life different from those existing in the layers of shallower & greater depths.

    I'm gonna pass along a tidbit, just out of curiosity as to what you might do with it. I heard this from a heterodox physicist but still believe that, as much of it as I tell you, is true. Though the speed of light is considered as a constant, that is apparently not really the case. Just as sound moves at different speeds through different media, so it would seem does light, or electro-magnetism. The, "constant," speed given for light is I think it's the speed while moving through a vaccuum, though it might also be an average speed, I forget which.

    See if you can use that to come up with something better than, or at least to help out, your idea of speeding up light by manipulating the speed of the space through which it is travelling. Perhaps you can come up with something less comical than the way you worded it, in post #46 (p.2), "You can travel faster than light if the space is moving with you." But thanks for the chuckle.
     
    Last edited: Nov 9, 2020
  3. HereWeGoAgain

    HereWeGoAgain Banned

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    We know how to make a time machine now. Circumnavigate a black hole at the proper distance and speed. After making a full loop you will back at the moment you entered.

    But unless you understand General Relativity, you have no way to comprehend this mathematical fact.
     
  4. DEFinning

    DEFinning Well-Known Member Donor

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    So in other words, if the black hole had been drawing to it a moderately nearby star which went supernova before reaching the black hole, & you were to find yourself in the unfortunate position of being caught in between the two, you would merely have to circumnavigate the black hole at the proper distance & speed, and the exploding, nearby star would never reach you? That's some theory; I hope neither of us ever has to put it to the test. Even if it worked, forever circling a black hole wouldn't be how I would care to spend eternity. (Before you get mad, I want to point out that I was on your side of the argument in post #52, just a little above here).
     
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  5. HereWeGoAgain

    HereWeGoAgain Banned

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    I am merely stating a fact from General Relativity. I would be hard-pressed to reproduce the calculations now but it is entirely mainstream physics and I've done the calculations myself in a graduate physics class.

    Another interesting calc using the Schwarzschild metric: If you go beyond the event horizon of a black hole, space and time reverse roles. So for example, if you could survive that long, hitting your rocket thrusters causes a change in time, not space..
     
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  6. HereWeGoAgain

    HereWeGoAgain Banned

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    For a quick look at closed timelike curves, you can read this article

    https://www.thoughtco.com/closed-timelike-curve-2699127

    What is unique about the black hole solution is that it allows us to follow one of these curves. We don't need a time machine. The black hole IS a time machine. That means it is not theoretical. We could actually do this.

    We actually measure the same effect here on earth to a very small degree. It is called frame dragging and we have to compensate for it in satellites. .
     
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  7. DEFinning

    DEFinning Well-Known Member Donor

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    Thanks, I really appreciate the links. I will have to pore over them so as to be better-versed in the concepts before floating more of my own theories. Only thing, though, is that another poster on this thread, Monash, is talking as if he has done some study in this area (though not necessarily at the Graduate -studies level) and what he says about time loops is in direct contradiction to your assertions (see post #51). Is this possibly just because all the experts are not in agreement?
     
  8. HereWeGoAgain

    HereWeGoAgain Banned

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    It is most likely because the black hole solution is a special case. There is no disagreement. This isn't politics. This is science. Opinions have no place. If he disagrees with me then he is wrong and needs to be corrected.

    After a quick review, it is clear that he is talking about something entirely different and completely theoretical. Apples and oranges.
     
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  9. HereWeGoAgain

    HereWeGoAgain Banned

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    One real limitation apparently built into any real time machine, is that you can only go back in time to the moment it was first turned on. In the case of the black hole solution, you effectively turn the machine on when you enter orbit of the black hole. So that is as far back in time as you can go.
     
  10. DEFinning

    DEFinning Well-Known Member Donor

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    Is it possible for you to explain this Alcubierre warp drive for a lay-audience (albeit a very smart one)? When I read kazenatsu's sentence that claimed, "you can travel faster than light if space is moving with you," it seemed on par with the contention that one can avoid injury, if ever in a free-falling elevator, by jumping upward just before it strikes bottom.
     
  11. DEFinning

    DEFinning Well-Known Member Donor

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    That much I had heard already; however, until we do any of these things, which I think will be (at least) a long, long way off, I still consider it all very theoretical.

    I will float one more theory, though. I think it will prove to be, if & when the time comes, a much more practical undertaking for one's consciousness to be projected through Time, than one's physical being.
     
  12. Aleksander Ulyanov

    Aleksander Ulyanov Well-Known Member

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    That's similar, yes, but there is more. In Jack Finney's book Time and Again the military has this hangar where people live in environments that try to duplicate past eras down to the last detail. This is not as ridiculous an idea as to time travel as it may seem. Roger Penrose is the leading physicist who believes that time itself may be nothing more than a human construct and that if we believe strongly enough that it's a hundred years ago it will BE then rather than now. Or maybe I misunderstand, I still have problems even with comparatively simple quantum relativity and Philip K. Dick's VALIS Universe.
     
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  13. Bowerbird

    Bowerbird Well-Known Member

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    Give Fred Trump a packet of condoms
     
  14. Monash

    Monash Well-Known Member

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    Wikipeida does a good job. The concept is named after the physicist who first described it - as more of a thought experiment than a serious proposal. Space is warped around the ship (compressed in front of the ship along its proposed line of travel and stretched behind) - a process that, if it could be done would appear to require either enormous amounts of energy or some form of exotic matter.

    Although Dr Alcubierre was the first physicist to mathematically describe such an FTL 'drive' i.e. one that conformed with the requirements of General Relativity other models have been proposed since. Importantly all have major drawbacks in terms of the physics involved/practical implications. So to date there is no evidence to suggest any of them would actually work. What further research/experiments in physics will show?
     
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  15. DEFinning

    DEFinning Well-Known Member Donor

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    They're mesmerizing. I haven't seen them fresh, before; or, at least, never realized it. I once bought a kit, but never got around to/had an acceptable place to put the box that it instructs one to build.

    In his book that I read, he spoke not of large doses, but of our ancestors eating small amounts, on a regular basis. People under the influence of these amounts, actually perform better on various visual acuity & reaction-time tests.
     
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  16. DEFinning

    DEFinning Well-Known Member Donor

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    Just to refocus the thread-- as a gesture for what part I've played in pushing your main interest, I think, to the side-- let me first recap that no poster, that I recall, has yet championed the idea, in opposition to what mainstream science currently maintains, that travel back in time is possible. So, perhaps this thread could narrow, or evolve, to the questions: who would be willing to be delivered into the future, not knowing what you could expect? How far would you go?

    But that is only a suggestion, if you/we all are interested in staying consistent w/ present theory. Until that determination becomes clear, I'm going to step back to where you began the thread, postulating on the pluses of living in an era, gone-by.

    I think, for most of us, it would be unpleasant to go back too far. As much as we might complain & find fault with today's status quo, unless we are currently, "homesteading," we have likely become very accustomed to things like indoor plumbing (toilets & running water), electric lighting, refrigeration, heating, washing machines, automobiles, telecommunications or at least a phone line, television, and other electric appliances & modern conveniences including even, for some, computers & smart phones. Just think about the last time you lost power for a week, or for even a couple of days.While we might well be able to eventually get used to living w/o those things, we'd be unlikely to completely forget about them.

    All that said, there are some isolated examples of a couple of those things or their analogs existing in certain places & at certain times in the past (during the Middle Ages, & in Rome, for example). And, of course, we could bring the ideas with us, if we have the proper skills & our new time possess the necessary technological resources.

    Yet, a potential trade-off might be if, by the time any of this is possible, it also becomes feasible to separate consciousness from our physical forms (I just want to stick in that I'm not supporting the idea that any of these things will ever be a reality, & certainly not in the next couple of centuries). IMO though, consciousness would be easier to project through, "time," than would a living body (esp. one that it was hoped would remain living, for the duration of the trip).

    In that case, we would not need be subject to the physical privations, though so would we be limited to the non-corporeal pleasures of that time. Does anyone think it's possible that some of today's, "ghosts," could be potential time-travellers, maybe who got lost?

    Final difficulties. Though I'm relatively happy w/ my proficiency using modern American English, I'm not great at foreign languages, probably in part due to how well-ingrained, in my mental circuitry, is my native language (& for most of us, if we're older, learning new tongues becomes more difficult). So I, for example, see the 19th century as a high-point in both music & visual art, & also in artist culture; that is, it was a time when one could easily find others with great passion for their, often revolutionary, artistic visions, & there were many, & ultimately very influential, groups who offered both comradery & lively debate. But to partake of all that (which, for the human element, I would much prefer to do in physical form), I would want to be in Europe, specifically France.

    But I don't speak French, not to mention French of 150 - 200 years ago. How disappointing it would be to, after listening to a live concert by Chopin, not to be able to pass along my admiration. Or to look at great paintings but have to pass up meeting the artists & joining them in night-long, group revelry & animated discussions, of art, philosophy, & life. BTW, though I respect the dedication of the Impressionists, & esp. appreciate the skill of some, like Renoir (who also had the wisdom to say, of all the artistic theorizing, that theories were merely a way for an artist to explain the shortcomings of their work), the group I put on the highest pedestal & with which I would most want to engage in deep conversation, is the NATURALISTS.

    So as to keep this thread positive, I guess we can assume, if science could do what even scientists, today, say isn't possible-- deliver me into the past-- it would also be able to create some type of linguistic tool that would immediately, and accurately, translate both the multiple speaking voices around me, as well as my own, modern-languaged thoughts, into the correct idiom.
     
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  17. DEFinning

    DEFinning Well-Known Member Donor

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    Here's one more idea to revive this thread. For those who feel an affinity w/ people from past eras, since we're apparently sticking to the theory that time travel can only be forward, how about trying to describe how people from those bygone days, were they to travel to the present day, would interpret the new world in which they found themselves? What might they do here?

    For any who are wondering how a time machine could get back to them, let us speculate that the technology was extraterrestrial, brought to Earth, & used for the hypothetical trip w/o any record being left. In fact, the travellers from the past could only just be arriving now. Poster's choice as to whether, in some sort of experiment, the ETs sent the humans to the future (where they have observer-androids waiting?), or whether our travelers accidentally engaged the alien technology, trying to escape after being abducted for other, more routine, probings.
     
  18. Jack Hays

    Jack Hays Well-Known Member Donor

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    For those who would go back in time, I have only one word of warning: dentistry.
     
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  19. garyd

    garyd Well-Known Member

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    Assuming the unlikely event you can actually do any damage. There was a sci-fi short story I read back in the sixties, Silverberg, I think, but I'm not sure, wrapped around the notion that each persons time line is discrete.
     

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