How could the experiment work and not permit a paradox?
Suppose the particle emitter apparatus is wired to a particle detector and will only send a particle back in time if it detects that no particle has been sent back. - You’d end up not sending a particle back in time and preventing the apparatus from sending the same particle back in time, in which case it wouldn’t send and therefore there would be nothing to prevent it happening, so it could be sent… etc… Grandfather paradox on a particle scale.
One interesting point they made in the show - when he turns the machine on, it’s possible that it will immediately start receiving signals from his future self, or from other researchers conducting the same experiment. As someone else pointed out, time travel, if possible, will only be possible back to the point where the machine is switched on (how sure are we about that?)
Regarding verifying his results - if he claims success, his peers are not just going to take his word for it and pat him on the back - they’ll try everything to challenge his findings, as they should.
One method of time travel requires there to be a machine at each end. We can’t receive visitors in time until we make the first machine. Your theory doesn’t negate the possibility of this type of time travel.
AHunter3 I think I understand you, your saying (to use my own anology) time is like a movie still in the roll can. each frame (equivelant to a point in your graph anology) if looked at in order produces a movie. however it’s in the roll can and not in a projecter. The way we experance time is like if the movie was viewed. now is the frame in front of the light, the future is the part of the film in the feed roll, the past is the part of the film in all ready viewed roll. it feels like there should be a projector but there is not. the projecter is illusion as our mind and exparance is just a function of how each frame is almost but not quite like the frame before it.
when you think of time as a spacial dimention and everything is just static usefull time travel seems impossible. However condersder this. what if the universe has a time plane instead of a time line? a plain composed of lines of time almost but not quite like the line before it. while everything would still be static we would have the illusion o being able to change the past. who knows maybe the extradimentions for string theory are not compactified but just extra time dimentions.
When speaking of time travel, people often make a big deal of the “grandfather paradox” - whereby I travel back in time and kill my own grandfather, thereby negating my existence.
How about the even weirder (IMO) situation of being able to meet myself at a past or future time?!
I believe this theory was expanded and popularized by the SF writer Larry Niven.
Paraphrased: Time travel is impossible. As soon as it exists, people start going back in time and mucking with history. The thread of history is changed. Sooner or later, one of these changes alters the future world enough so that time travel is not invented, and you’re back where you started.
netscape 6 I think I like your description better than mine. Yeah, that’s exactly what I meant.
Hmm. Hmmmmmm. And our consciousness has only “been a projector” along one line within the time plane? Well, I guess we could “rewind at a 45° angle” and “go” back to a “past” (if that’s still the word for it) other than the one we remember, but it seems like it would still be true that we can only be the projector’s light bulb in the places where the projector “is”, i.e., if H G Wells goes back 1 year but at an angle askew to the line of events he consciously experienced, he’d still “land” as whoever or whatever “H G Wells” was (“was”? wow, is our language ever inadequate for this!) and, once having “landed” there, would still experience the thoughts and memories of whoever or whatever “H G Wells” is/was/would’ve been on that alternative timeline that is distinguished from the timeline he originally experienced life on by some distance along dimensional parameter w or r or whatever. And therefore he still would not be cognizant of being “H G Wells, who came from the (ahem) ‘future’ to see this”.
While those of you with a much better grasp of this than I are discussing this, would you permit another, related, question ?
Does time travel necessitate space travel ? That is, it seems to me that, were I to be able to travel back in time six months, and do so, say on the vernal equinox, that I would show up with the earth at the autumnal equinox (where it was six months prior to my departure) and me roughly 186 million miles away (actually, more than that, especially considering that Sol is in motion, as well).
The Earth spins on its axis, orbits the sun, which itself orbits the center of the galaxy…and the galaxies are expanding away from each other at a rate proportional to the Hubble Constant.
If we are calculating time travel coordinates, we must take into effect that any three coordinates on earth will be somewhere else given a different time differential.
I would not call our minds the projector. What I meant was out interprtation of our existance is the projector.
Think of it this way software is not for lack of a better word aware of how the computer it’s on works. It does not know the princples and design behind a cpu for example, or that copper conducts electricity. It just knows stuff like i++ increases the variable i one value.
Now imagen a 3D shadow of sorts for 4D time space. each particle would not be a point but instead be a line. Each of these lines are arranged based on other lines accourding to a complex set of rules. Our existance is to that tangled mess of lines as software is to hardware. The projector is no more real than a context menu.
Are you saying the atoms that make up HG Wells will (or maybe would?) reform into what ever they were doing in the past when Wells makes his trip back to the past? I remember each particle is suppossed to be inexplicably connected to every particle it interacted with. Maybe a particle is severly entangled with it’s self. Then again I’m a nonquantum physicist wildly speculating on quantum mechanics. So I’m guessing I’m full of it.
Now to post this and see all the typos I missed while proof reading.
I would not call our minds the projector. What I meant was out interprtation of our existance is the projector.
Think of it this way software is not for lack of a better word aware of how the computer it’s on works. It does not know the princples and design behind a cpu for example, or that copper conducts electricity. It just knows stuff like i++ increases the variable i one value.
Now imagen a 3D shadow of sorts for 4D time space. each particle would not be a point but instead be a line. Each of these lines are arranged based on other lines accourding to a complex set of rules. Our existance is to that tangled mess of lines as software is to hardware. The projector is no more real than a context menu.
Are you saying the atoms that make up HG Wells will (or maybe would?) reform into what ever they were doing in the past when Wells makes his trip back to the past? I remember each particle is suppossed to be inexplicably connected to every particle it interacted with. Maybe a particle is severly entangled with it’s self. Then again I’m a nonquantum physicist wildly speculating on quantum mechanics. So I’m guessing I’m full of it.
Now to post this and see all the typos I missed while proof reading.
I believe that maybe we are getting future messages or “time travelers” in our own time. We just might not be listening. The practicality of sending an actual organism backward into time without killing it might be a time travel barrier. We could alter the past indirectly with time transmissions- Controllable waveforms or quantum manipulation.
Every person you have ever met is a time traveler. Everyone is moving through their own timeline, which is in reality variable to your own. We move through time at slightly different speeds, some of us are coming from the recent past or the recent future relative to your own timeline.
There are probably many naturally occurring temporal states or temporal anomalies that we experience, but because they are built so deeply into the nature of our reality in the forward slipstream of time that it is very hard to perceive or even notice and often is misppropriated by the unknown, spiritual, or paranormal. Maybe after the first successful transmission into the past, they found something out about time travel and time travel experiments were banned.
I only saw a bits of it, but can I still say that that was one of the worst documentaries I’ve ever watched? They never really explained how this “incredible” machine was supposed to work, and the incredibly bad acting/wardrobe job done on the “future” classroom made my brain hurt.
That, plus the fact that all the action shots I saw of the prof were apparently from an introductory physics class… well, that’s why I didn’t see the end of it. Judging from the other remarks, I count myself lucky
The OP should perhaps spend a little time thinking out carefully what exactly would constitute evidence of “time travel.” Because what most people mean by it is not merely physically but logically impossible – makes as much sense as Jabberwocky.
What most people seem to mean by “time travel” is: there exists some interface between me and the rest of the world – the window of my spaceship, the boundary around my time machine, et cetera – and, when I look at things inside this boundary, e.g. at myself, my body processes, heart beating and lungs breathing, thought sequences and so forth, I observe causality: in brief, effects follow causes. However, when I look at things outside this boundary, e.g. at the birds flying by, the aging of other people, trees, stars, et cetera, I observe inverse causality: effects precede causes, or at least, the order of “cause” and “effect” I observe inside the interface is reversed outside the interface.
But this is nuts. However the universe works, it cannot operate by one set of rules on one side of a “window” and by a set by definition contradictory on the other, and still allow me to “look” out the “window.”
Which is to say, whatever the physics of time ever displays, it will never display something which can be interpreted as “time travel” in the colloquial meaning of the phrase, I think.
That this question can even be asked is simply proof that English is a sufficiently inconsistent logical system that propositions can easily be formulated in it which scan lexically despite being logically void. This question is a lot like asking “What would it feel like to have never been born?” (I am drawing an analogy between the physics of the conventional view of TT and the logical proposition “If A and not-A, then . . .[some question]. . .”) The only reasonable answer is: mu.
